Effects Of Deglutition And Speech Training On Dental Overjet

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Content This dissertation has been
microfilmed exactly as received 70-8544
STANSELL, Barbara Jones, 1917-
EFFECTS OF DEGLUTITION AND SPEECH
TRAINING ON DENTAL OVERJET.
University of Southern California, Ph.D., 1969
Speech Pathology
University Microfilms, Inc., Ann Arbor, Michigan
© C opyright by
BARBARA JONES STANSELL
EFFECTS OF DEGLUTITION AND SPEECH TRAINING
ON DENTAL OVERJET
by
Barbara Jones Stansell
A Dissertation Presented to the
FACULTY OF THE GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(Communicative Disorders)
June 1969
UNIVERSITY O F SO UTHERN CALIFORNIA
THE GRADUATE SCHOOL
UNIVERSITY PARK
LOS ANGELES. CALIFORNIA S 0 0 0 7
This dissertation, written by
................JRsjr.Taam .J.ojcifis..Stans.eJlL.................
under the direction of hsjr.... Dissertation Com
mittee, and approved by all its members, has
been presented to and accepted by The Gradu
ate School, in partial fulfillment of require
ments for the degree of
D O C T O R OF P H IL O S O P H Y
ACKNOWLEDGMENTS
The research for and the writing of a study of this
kind are not accomplished in a vacuum. Without the help of
many individuals, such a study would not come to fruition.
Among those to whom the author is indebted for help are the
following:
Winston Nelson, Superintendent, and Virginia Covey,
Director of Elementary Education, Pomona Unified School Dis
trict, who permitted and encouraged the research to be done
in the elementary and junior high schools of Pomona, Cali
fornia.
All of the speech clinicians of Pomona Unified
School District who helped screen children for subject
selection; but I am especially indebted to these clinicians
who assisted with the training: Joan Graefe, Helen Kowite,
Mary Natale, Sophia Pearman, and Pauline Stone.
Four orthodontists who examined the children and
made dental impressions without monetary remuneration: Doc
tors Robert Foresman, Murray Hamburg, Juan Hutchings, and
Sidney Meek. Many thanks, too, are due to these orthodon
tists' assistants.
The Southern California State Dental Association
ii
which awarded a research grant that was helpful in meeting
the expenses of the investigation.
Finally, I want to acknowledge the unstinted and
devoted assistance of the two Jims in my life.
TABLE OF CONTENTS
Page
ACKNOWLEDGMENTS ii
LIST OF TABLES vi
LIST OF FIGURES viii
Chapter
I. INTRODUCTION 1
Statement of the Problem
Questions and Hypotheses
Importance of the Study
II. REVIEW OF THE LITERATURE 6
Methods Used by Different Examiners in
Determining the Presence of Tongue-
Thrust Swallow
Tongue-Thrust Swallow and Speech Defects
Tongue-Thrust Swallow and Malocclusion
Speech Defects and Malocclusion
Research Design
Operational Definitions of Terms Used
Subject Criteria
Materials and Apparatus
Procedures
Data Analysis
Experimental Speech Group
Experimental Deglutition Group
Comparison of Sigmatism Training, Deglutition
Training and No Training on Dental Overjet
The Unmatched Subjects
Discussion
III. METHODS AND PROCEDURES 38
IV. RESULTS AND DISCUSSION 76
Chapter ' ...... ' ~ Page
I
I V. SUMMARY, CONCLUSIONS AND IMPLICATIONS ........ 84
i !
The Problem |
The Method
Results !
Conclusions !
Implications j
GLOSSARY.............................................. 9oj
APPENDIXES !
A. Orthodontic Examination Form ................... 96
B. Parent Information .............................. 98
C. Judges' Check List of /s/ and /z/ Words from
Passages I, II, and I I I ..................... 100
D. Summary of the Analysis of Variance Employed to
Test Difficulty Differences among Passages I,
II, and I I I ................................. 104
E. The Plastic Mouthpiece.......................... 106
F. Lip Exercise.................................... 108
G. Instructions to the Judges..................... 110
H. Inclination of Mandibular Incisors ............. 112
I. The Total Number of /s/ and /z/ Errors of the
Three Matched Groups before Any Training Was
Initiated, the Averages of the Judges'
Ratings, and the Mean Number of Errors
for Each Group............................... 114
J. The Total Number of /s/ and /z/ Errors of the
Experimental Speech Subjects on the Second
and Third Recordings, the Averages of the
Judges' Ratings, and the Mean Number of
Errors on Both Recordings................... 116
K. Total Number of Consecutive Error-Free
Sessions of the Experimental Deglutition
Subjects before the Second X-Ray and the
Number of Error-Free Sessions between
the Second and Third X-Rays................. 118
v
Chapter
j L. Pre- and Post-Test Measurements of the Dental
Overjets of Subjects Who Received Only
I Speech Training, the Differences
between These Measurements, and
! the Mean at Each Time of Measurement . . . .
i
M. Pre- and Post-Test Measurements of the Dental
Overjets of Subjects Who Received Only
Deglutition Training, the Differences
between the Measurements, and the
Mean at Each Time of Measurement ..........
N. Comparison of the Differences between the
Initial and the Post-Test Dental Overjet
Measurements of Subjects in the Three
Matched Groups and the Mean for Each
G r o u p .......................
0. Number of /s/ and /z/ Errors Made by the
Unmatched Subjects before Any Training
Was Initiated, the Averages of the
Judges' Ratings, and the Mean for
the Group . . .............................
P. Comparison of the Differences between Pre- and
Post-Test Dental Overjets of the Unmatched
Group and the Means for Pre- and Post-Test
Measurements ...............................
LIST OF REFERENCES.......... ......................
Page
' l
120;
I
i
i
122;
1
124
126
128
130
vi
LIST OF TABLES
Table Page
1. The Three Matched Groups: Sex, Age, and Angle's
Classification ............................... 50
2. Summary of the Analysis of Variance of the
Difference Scores of the Three Matched
Groups....................................... 79
3. Summary of the Scheffe Test of Post Hoc Compari
sons of the Differences between the Group
M e a n s ....................................... 80
4. Pre- and Post-test Differences in the Distance
from Point B to Midpoint of the Mandibular
Incisors (Inclination of the Mandibular
Incisors) for the 3 Matched Groups.............. 113
5. The Total Number of /s/ and /z/ Errors of the
Three Matched Groups before Any Training
Was Initiated, the Averages of the
Judges' Ratings, and the Mean
Number of Errors for Each Group............... 115
6. The Total Number of /s/ and /z/ Errors of the
Experimental Speech Subjects on the Second
and Third Recordings, the Averages of the
Judges' Ratings, and the Mean Number of
Errors on Both Recordings.................. 117
7. The Total Number of Consecutive Error-Free
Sessions for the Experimental Deglutition
Subjects before the Second S-Ray and the
Number of Error-Free Sessions between
the Second and Third X-Rays................ 119
8. Pre- and Post-test Measurements of the Dental
Overjets of Subjects Who Received Only
Speech Training, the Differences between
These Measurements, and the Mean at Each
Time of Measurement .................. 121
vii
Table ' .....' ‘ ' ' .....
9. Pre- and Post-test Measurements of the Dental
Overjets of Subjects Who Received Only Deglu-
i tition Training, the Differences between the
: Measurements, and the Mean at Each Time of
Measurement ............ ................
| 10. Comparison of the Differences between the
Initial and the Post-test Dental Overjet
Measurements of Subjects in the Three
; Matched Groups and the Mean for Each
Group .....................................
11. Number of /s/ and /z/ Errors Made by the
Unmatched .Subjects before Any Training
Was Initiated, the Averages of the
Judges' Ratings, and the Mean for
the Group .................................
12. Comparison of the Differences between Pre- and
Post-Test Dental Overjets of the Unmatched
Group and the Means for Pre- and Post-test
Measurements ...............................
Page
j
1 2 s |
125
127
129
viii
LIST OF FIGURES
Figure Page
1. Illustration of the Measurement of the Dental
Over j e t ..................................... 61
2. Points Utilized in Tracing the Head Films . . . 62
3. Planes Utilized in Tracing the Head Films . . . 63
4. A Complete Head Film Tracing Illustrating the
Angles Measured . ......................... 65
5. Pre- and Post-test Differences of the 18 Control
Subjects..................................... 69
6. Increase and Decrease Differences between Pre-
and Adjusted Post-test Dental Overjets of
the 18 Control Subjects..................... 70
7. Relation of Differences between Pre- and
Adjusted Post-test Dental Overjet to
Differences between Pre- and Post-test
Distance from Point A to Midpoint of
Maxillary Incisal Profile of the 18
Control Subjects........................ 71
8. Tracing of the Final X-Ray of the Same Control
Subject Shown in Figure 1 ................... 73
ix
CHAPTER I
INTRODUCTION
Possible relations between speech production and :
dental malocclusion have long been a controversial subject
in both dentistry and speech pathology. The controversy now;
concerns malocclusion, speech production, and muscular func
tion. Research has shown a positive correlation between the
so-called "atypical" patterns of tongue and swallow behavior
and the distortion of certain phonemes, particularly the
sibilants and more specifically the /s/ and /z/ (Fletcher,
Casteel, and Bradley, 1961; Ward, Malone, Jann, and Jann,
1961; Subtelny and Subtelny, 1962; Kortsch, 1963; Jann,
Ward, and Jann, 1964; Subtelny, Mestre, and Subtelny, 1964;
Ronson, 1965).
The results of some research investigating faulty
speech and malocclusion range from no relationship (Carrell,
1936; Frowine and Moser, 1944; Bernstein, 1954) to a posi
tive relationship (Fymbo, 1936; Fairbanks and Lintner, 1951;
Rathbone and Snidecor, 1959). There was some agreement that
the phonemes most often associated with malocclusion are the
sibilants (Fymbo, 1936; Wepman, 1937; Bloomer, 1957; Strang
hnd Thompson, 1958; Rathbone and Snidecor, 1959; Hahn and
Sloan, 1966; Carrell, 1968).
j It has been suggested that faulty speech can change
l
the continuity of the dental structures (Strang and Thomp
son, 1958; Harrington and Breinholt, 1963; Graber, 1966).
'Schurter (1962) advanced the opinion that certain techniques
used to correct lisping would cause a labial deflection of
the incisors.
The most recent research has linked tongue-thrust
swallow to both malocclusion and faulty speech, particularly
the sibilants (Ward, Malone, Jann, and Jann, 1961; Subtelny
and Subtelny, 1962; Jann, Ward, and Jann, 1964; Subtelny,
Mestre, and Subtelny, 1964). It has been suggested that
when lisping and tongue-thrust swallow coexist, the swallow
ing pattern should be altered before speech correction was
initiated (Fletcher, Casteel, and Bradley, 19 61; Jann, Ward,
and Jann, 1964). Fletcher, et al., suggested that altering
the swallowing pattern would correct mild articulatory prob
lems. Research consisted of surveys that indicated a rela
tion between tongue-thrust swallow and faulty sibilants.
Suggestions concerning training were offered, but there was
a conspicuous lack of research that indicated the effects of
any type of training.
Statement of the Problem
It has been suggested that certain speech correction
techniques would cause a labial deflection of the incisors,
thereby increasing the amount of the dental overjet
i(Schurter, 1962), Subtelny, Mestre, and Subtelny (1964)
used static roentgenography and showed that speakers with
defective /s/ articulation excessively fronted the tongue
tip. If lispers were instructed to produce sibilants with
the teeth closed and were given no instructions regarding
tongue placement, it would be reasonable to assume that a
labial deflection of the incisors would result due to muscu
lar pressure. One phase of the problem pertaining to the
present study was to determine if a corrective technique
could be devised that would not result in muscular pressure
on the incisors during the production of speech sounds.
It was reasonable to assume that cessation of lin
gual pressure against the incisors during swallow and that
employment of the muscles of facial expression to exert a
lingual pressure on the maxillary incisors would result in a
decrease of the dental overjet. However, no research has
been found that substantiates this asssumption. Direct
observation of a subject or comparison of dental impressions
before and after deglutition training would give no indica
tion whether a decrease in the overjet was the result of
training or the result of a change in the relationship of
the mandible to the maxilla, or the result of both.
The general purpose of this study was to investigate
separately the effect of deglutition correction and the
effect of a particular type of speech correction on dental
I I
overjet and to compare the efficacy of the two types of j
j I
training. j
j |
: i
Questions and Hypotheses
The specific purpose of this study was to answer the;
following questions:
1. Will correction of sigmatism by the particular
speech technique employed in this study decrease the
dental overjet?
2. Will correction of deglutition decrease dental over
jet?
3. Will correction of the pattern of deglutition result
in a greater decrease in the dental overjet than the
correction of the defective /s/ and /z/ in subjects
who exhibit tongue-thrust swallow, sigmatism, and a
dental overjet?
The hypotheses derived from these questions were:
1. After the correction of sigmatism by the particular
technique employed in this study, the mean of the
final adjusted dental overjets of the speech group
will be significantly less than the mean initial
measurement.
2. The mean final adjusted dental overjet of the deglu
tition group will be significantly less than the
mean initial measurement.
3. Deglutition training will result in a significantly
greater mean decrease in dental overjet than will
! speech training.
i
!
i
Importance of the Study
I
! No reference in the literature was found that indi-
i
;cated that any attempt had been made to evaluate the align
ment of teeth before and after any type of training other
than orthodontic treatment. There was an abundance of
literature describing various speech training techniques,
but none indicated whether these techniques would achieve
acoustical quality without deleterious effects upon the
dentition. Because no effort has been made to determine
differences in dentition resulting from training, it was
important to quantify the effects of two specific types of
training on the incisal teeth.
! CHAPTER II
REVIEW OF THE LITERATURE
Discussion of the literature has been organized
around the following topics: (1) methods used by different
examiners in determining the presence of tongue-thrust
swallow, (2) tongue-thrust swallow and speech defects,
(3) tongue-thrust swallow and malocclusion, and (4) speech
defects and malocclusion.
Methods Used by Different Examiners
in Determining the Presence
of Tongue-Thrust Swallow
Terms applied to tongue-thrust swallow include:
abnormal, atypical, infantile, visceral, reverse, tongue-
thrust reflex, orofacial muscle imbalance, and the syndrome
of oral-mechanism imbalance. These terms and the methods
used in determining the presence of "abnormal" swallow have
evolved from early definitions of "normal" swallow.
Truesdell and Truesdell (1937) presented, in 1924, a
paper which described a "gulp-like" swallow in many cases
with severe malocclusion. The Truesdells had studied the
swallowing of animals and humans with normal occlusion and
had observed that occlusion was not relaxed until the bolus
of food had passed the larynx. It was found that the mus- j
cles of facial expression did not enter into normal degluti-j
tion. Three types of abnormalities were described:
!(1) abnormalities immediately preceding deglutition,
(2) abnormal function of the lips and jaws, and (3) abnor
malities in which the tongue was involved as well as the
lips and jaws.
Rix (1953) described two types of swallowing consid
ered to be abnormal: (1) the infantile or suckling type
which resembled the behavior of the breast-feeding infant
and (2) the type in which the tongue remained within the
dental arches but the teeth were separated and the lips were
active. Rix considered the tooth-apart swallow to be an
important manifestation of abnormality and concluded from
his research that dental overbite varied directly with the
amount of tooth separation.
Gwynne-Evans (1954) considered tooth-apart swallow
(which he termed "visceral") to be merely an infantile pat
tern that would, with maturation, merge into normal swallow
(which he termed "somatic"). However, his clinical experi
ence did not support that opinion. It was concluded that
the distinction between normality and abnormality in deglu
tition was difficult and that visceral swallowing was often
associated with abnormal occlusion and somatic swallowing
was often associated with normal occlusion.
Straub (1960) was of the opinion that the muscles of
facial expression were not used in normal swallowing and
i
that any observed changes in facial muscles prior to or dur
ing the act of swallowing usually indicated an abnormal
swallowing habit. His criteria also included pressure of
the tongue against the incisors and lack of action of the
muscles of mastication during swallowing.
According to Fletcher, Casteel, and Bradley (1961)
it was basically agreed that the deviant swallow pattern
included (1) extreme tension in the musculature that
enclosed the mouth, (2) dimunition or absence of palpable
contraction in the muscles of mastication during swallowing,
and (3) forward protrusion of the tongue. All three crite
ria were required for a positive identification of deviant
swallow.
Ward, Malone, Jann, and Jann (1961) and Jann, Ward,
and Jann (1964) noted circumoral lip action, separated
teeth, and visible spread of the tongue between the anterior
incisors during swallow. It was not stated whether or not
all of the three criteria were required for determination of
the presence of "visceral" swallow.
Rogers (1961) observed tongue and facial action both
during the swallow of water and during the swallow of
saliva. Swallowing was repeated by the patient until the
operator was able to determine the presence or absence of
anterior or posterior tongue-thrust. Rogers examined 497
orthodontic patients and 290 elementary school children, who
ranged in age from 5 to 12 years. No grimace was shown by 3
of the 165 school children who manifested tongue-thrust dur
ing deglutition, but grimace was shown by 11 of the 125 non
thrusting children. No grimace was shown by 8 of the 312
orthodontic patients who exhibited tongue-thrust during
deglutition, but grimace was shown by 46 of the non-thrust
ing patients. It was concluded that in some cases the mus
cles of facial expression played a role in a normal swallow.
Rogers' conclusion agreed with the opinion of Strang and
Thompson (1958) that perioral action was an aid to normal
swallowing.
Kortsch (1963) determined the presence of "tongue-
thrust reflex" when he observed the protrusion of the tongue
between the incisal edges of the upper and lower anterior
teeth, the dropping of the jaw, and the forcible closing of
the lips with strong contraction of the mentalis muscle.
Subtelny and Subtelny (1962) based determination of
tongue-thrust upon the observation of the protrusion of the
tongue between the incisors and the projection of the tongue
beyond the lower incisors during the act of swallowing. The
Subtelnys also observed lip function in 51 subjects with
Class II, Division 1 malocclusion. The sample was divided
into two groups: (1) 31 subjects with normal speech and
(2) 20 subjects with defective /s/ production. Approxi
mately 22 per cent of the normal speakers were found to have
an excessive function of the musculature in the lower lip
r .....' .................... 10
j
region; but when excessive lower lip function was evident,
a thrust of the tongue was not evident. Also, many of the
children with tongue-thrust did not show excessive function
of the lower lip.
In 1964 Subtelny, Mestre, and Subtelny reported a
study in which a clinical appraisal of deglutition was made
of 48 subjects with Class II, Division 1 malocclusion.
Three separate evaluations of perioral and lingual activity
were made while the subject was swallowing a sip of water.
Assessment of lingual function was based on a four-point
scale:
1. Tip of tongue elevated appears to contact alveolar
tissue.
2. Tip of tongue elevated appears to contact lingual
surfaces of upper incisors.
3. Tip protruded (thrust) to extend between incisal
edges.
4. Tip and lateral margins protruded (thrust) between
incisal edges and occlusal surfaces of buccal seg
ments. (p. 279)
Ratings of 3 and/or 4 designated the presence of a tongue-
thrust. Assessment of perioral activity was similar in that
scores from 1 to 4 indicated greater degrees of muscular
activity during swallow. An attempt was made to evaluate
molar contact, but the two methods employed (palpation for
masseter contraction and eversion of the lower lip) were
found to be unreliable. It was found that tongue-thrust
lassociated with moderate or excessive perioral contraction
occurred in less than 10 per cent of the subjects with
malocclusion, and tongue-thrust with slight perioral activ
ity occurred in approximately one-third of the subjects with
malocclusion. More than 20 per cent of the subjects were
found to have no tongue-thrust, but they did have lip activ-
| ;
ity rated as moderate or excessive. It was concluded that
tongue activity during deglutition should not be predicted
on the basis of observed perioral activity.
Ronson (1965) questioned lack of masseter action as
a necessary criterion in determining the presence of vis
ceral swallowing, especially in subjects with open bites.
He also suggested the possibility that an individual would
perform normally upon an examiner-directed saliva swallow
but would swallow incorrectly during the act of eating or
drinking. One of the purposes of Ronson's study was to
investigate masseter contraction in 32 subjects who exhib
ited visceral swallow. Both of the following criteria were
required for determination of the presence of visceral
swallowing:
1. Tongue protruding through or pushing against ante
rior dentition;
2. Tight labial seal and/or overactivity of the obicu-
laris oris and mentalis. (p. 320)
Nineteen of the thirty-two visceral-type swallowers did not
show masseter contraction. Nine of the visceral-type swal
lowers had anterior open bite and masseter contraction.
Although the determination of visceral swallow by examining
a command saliva swallow was questioned, testing such a
r ~ ' ■ ■ ■ " 12
i
hypothesis was not included in the study.
! Cleall (1965) compared the traditional concepts
i :
between normal and abnormal swallowing and stated: "Normal i
swallowing is said to be occurring when the lips remain in
repose, the posterior teeth make contact, and the tongue
remains within the confines of the oral cavity" (p. 567).
Cinefluorography at 60 frames per second was used to compare
the swallowing of 28 subjects with excellent occlusion, 30
subjects with Class II, Division 1 malocclusion, and 27 sub
jects who clinically demonstrated a severe anterior thrust
during swallowing. The sole criterion for the selection of
the tongue-thrust group was the demonstration of a severe
anterior protrusion movement of the tongue during swallow.
It was found that 11 per cent of the "normal" subjects pro
truded the tongue beyond the incisors during swallowing and
I
swallowed without bringing the teeth into occlusion. Forty
per cent of the subjects in the "normal" group made no molar
contact during any phase of swallowing; but 60 per cent of
the subjects in the "normal" group achieved tooth contact.
Also noted was that, as a group, the "normals" required more
time to swallow water than to swallow saliva; and their
tongues were lower and in a more posterior position when
they swallowed water. Study of the "normal" group showed
that a protrusive forward movement of the tongue tip during
swallow would not necessarily be abnormal but would be
merely associated with a tooth-apart swallow. It was also
concluded that tooth contact during deglutition was probably!
a poor criterion for the classification of abnormal or
normal swallowing. However, Cleall mentioned the fact that i
actual determination of molar contact from the various
frames of cinefluorography was questionable. It was found
that 70 per cent of the subjects in the Class II group moved
the tongue anteriorly past the lower incisors. Cleall com
mented that the marked forward excursion of the tongue
appeared to be largely passive and not so vigorous as to
warrant the inclusion of these subjects in the tongue-thrust
group. Sixty per cent of the Class II group did not achieve
molar contact. The important differences noted between the
"normal" group and the Class II group were, in Cleall's
opinion, related to the marked dental disharmony presented
in the Class II group.
Hedges, McLean, and Thompson (1965) hypothesized
that children with normal occlusion, acceptable speech,
normal skeletal morphology, no history of oral habits, and
good medical histories would manifest normal tongue function
during both speech and deglutition. A sample of 22 Cauca
sian subjects was selected from 250 school children in
grades six, seven, and eight. Cinefluorographic filming of
252 swallows was recorded. Although variations within the
same subjects were observed, two distinct swallowing pat
terns were noted, one pattern with teeth together and one
pattern with teeth apart. Teeth-apart swallows were in the
majority. Facial muscular action was distinctly recognized,;
whether excessive or minimal, and was recorded as an inte
gral part of the teeth-apart swallow. It was concluded that
swallowing with teeth apart must be an acceptable pattern
because all other factors were considered acceptable. The
incidence of tongue-thrust swallowing in the group was
"startling." The explanation of the high incidence of
tongue-thrust in the particular sample studied was that the
amount of tongue pressure exerted, the resistance of the
alveolar bone, the degree of separation between maxillary
and mandibular incisors, the consistency and amount of the
bolus, and the force exerted by the perioral musculature
were other factors to be considered. It was concluded that
for a thrust to influence the dentition, it must be accompa
nied by such other factors as muscular tension or emotional
stress.
Summary
Methods of determining the presence of tongue-thrust
swallow have been developed from definitions of tongue-
thrust swallow which in turn have been developed from the
definition of normal swallow. The classic definition of
normal swallow has been as follows: the lips remain in
repose, the posterior teeth make contact, and the tongue
remains within the confines of the oral cavity. However,
recent research employing cinefluorography has cast some
doubt on what was normal and what was abnormal in the act of
ideglutition.
i i
Tongue-Thrust Swallow and Speech Defects i
Research
Fletcher, Casteel, and Bradley (1961) reported the
speech and deglutition examination of 1615 children, ranging
in age from 6 to 18 years, who attended schools that had no
speech correction or speech improvement programs. The inci
dence of subjects with tongue-thrust swallow was 668; the
incidence of subjects with sibilant distortion was 230; and
the number of subjects with coincidental problems of tongue-
thrust swallow and sibilant distortion was 181. (It should
be noted that the same investigators examined the subjects
for both speech and deglutition.) Findings revealed that
both tongue-thrust swallow and sibilant distortion in sub
jects without a tongue-thrust swallow were statistically
related to the age of the subject, but there was not a sig
nificant relationship between age and sibilant distortion in
subjects with a tongue-thrust swallow.
Ward, Malone, Jann, and Jann (1961) reported a pilot
study of the deglutition and articulation of 358 children in
grades one through three in schools which had no speech cor
rection programs. A pedodontist and two speech clinicians
independently examined 99 of the subjects for both swallow
ing behavior and dental occlusion. Because the findings of
the three examiners were identical in over 90 per cent of
the cases, the speech clinicians alone examined the degluti
tion and occlusion of the remaining 259 children and the
articulation of the entire sample. One of the trends noted
was that phoneme variations and visceral swallowing were
Coincidentally present in 79 per cent of the children; but
some of the children with visceral swallowing did not show
phoneme variations, and some of the children with phoneme
variations did not show visceral swallowing. Phonemes were
considered deviant not only if they were omitted or dis
torted but also if they were acoustically acceptable but
produced differently, specifically with the tongue tip for
ward, on, or between the incisors. Ward, et al., limited
their findings of the coincidence of specific sound devia
tions and visceral swallowing to include malocclusion.
Therefore, visceral swallowing plus malocclusion was present
in 55.2 per cent of the children with /s-z/ defects, in 47.9
per cent of the children with /l/ deviations, and in 43.3
per cent of the children with /t-d/ deviations. It was sug
gested that the high coincidence of visceral swallowing and
phonemic variations in children lends credence to the fre
quently reported clinical observation of speech therapists
concerning the concurrence of tongue-thrust and articulation
disorders found in the children in their caseloads. The
application of such terms as "abnormal," "atypical," and
"perverted" to tongue-thrust swallow in children in grades
one through three was questioned because the swallow behav
ior was so prevalent in the ages studied. Although the con-
elusions were presented as trends and should be subjected to
further verification, the investigators recommended that it
may be appropriate to reconsider the use of the term "func
tional" in describing the majority of articulatory defects
found in children in the elementary grades.
Jann, Ward, and Jann (1964) investigated the effect
of maturity upon the speech and deglutition of the subjects
previously studied by Ward, et al., (1961). A reexamination
of the children was conducted after an interval of one year
and again after an interval of two years at which time only
281 of the original number of 358 subjects were available.
Not only were phoneme omissions and distortions noted but
also the manner in which the phonemes were produced, even
though they were acoustically acceptable. It was found that
many children consistently produced the /l/ by placing the
tip of the tongue between the anterior incisors so that it
was easily visible although the sound was acoustically
acceptable. It was also observed that many children pro
duced the /s/ by placing the grooved tip of the tongue
lightly against the anterior incisors or on the alveolar
ridge, emitting the air stream centrally which produced an
acoustically acceptable /s/. However, the sides of the
tongue were not raised in closed contact with the upper
alveolar ridge were but protruded laterally between the
occlusal surfaces of the premolar and molar teeth. Subjects
who produced /!/ in the manner described and those who pro-
duced /s-z/ in the manner described were considered to have !
articulation variations. The same examiners made both
deglutition and articulation judgments. Fourteen of the ;
original 23 first-grade children who exhibited both tongue-
thrust swallow and /s-z/ variations showed both types of
behavior in the second grade and again in the third grade.
Sixteen of the 32 second-grade children who originally
showed both tongue-thrust swallow and /s-z/ variations
showed both when examined in the third grade, and 14 of the
subjects showed both when examined in the fourth grade. Ten
of the 22 children who showed both types of behavior in the
third grade retained them in the fourth grade, and 9 chil
dren retained them in the fifth grade. The investigators,
as in the original study, stated that this was also a pilot
study and that findings needed to be subjected to careful
verification. It was concluded that the high coincidence of
children with visceral swallowing and /s-z/ and /l/ varia
tions appeared to support the opinion of speech clinicians
who advocated training in the control of more basic oro
facial patterns before proceeding to training in the cor
rection of specific articulation variations.
Kortsch (1963) reported a study of 134 children who
were examined by a dentist and classified as having the
"tongue thrust reflex." They were examined by a speech
therapist for any substitution, omission, or distortion of
speech sounds, particularly /s/, ///, /t//, and /?/.
Kortsch concluded that tongue-thrusting was not necessarily
i
responsible for a speech defect but probably contributed to
it.
Subtelny and Subtelny (1962) investigated 51 sub
jects with Class II, Division 1 malocclusion and made cepha-
lometric headplates of each subject during the production of
the /s/ phoneme. A panel of three speech correctionists
judged, from tape recordings, 31 subjects to have normal
speech and 20 subjects to have a defective /s/. It was
found that 30 per cent of the normal speakers and 60 per
cent of the defective speakers had tongue-thrust swallow.
It was noted that the adaptation of the normal speech group
to the extreme Class II malocclusion frequently involved a
strong use of the lower lip during speech and swallowing.
The defective speech group did not adapt to the malocclusion
in this manner. Instead, they usually protruded the tip of
the tongue beyond the mandibular incisors during speech and
during swallow. It was concluded that tongue-thrust swallow
may well be a frequent, unrecognized cause of defective
speech but that it was apparent that some patients have
tongue-thrust during swallowing but have no speech defects.
They also concluded that some patients with speech defects
do not have tongue-thrust swallow.
Subtelny, Mestre, and Subtelny (1964) investigated
the relationship between tongue-thrust swallow and the
defective /s/. Twenty of the 81 subjects had defective
speech and Class II, Division 1 malocclusion; 30 subjects
had normal speech and normal occlusion; and 31 subjects had
Class II, Division 1 malocclusion and normal speech. A
clinical appraisal of deglutition was made on 48 of the 51
subjects in the malocclusion group. Fifty-eight per cent
did not have tongue-thrust. Forty-two per cent of the non
thrusters with malocclusion had good speech, and 17 per cent
had defective speech. Seventeen per cent of the group with
tongue-thrust and malocclusion had good speech; 25 per cent
had defective speech. When the data were regrouped on the
basis of speech, 30 per cent of the good speakers with
severe malocclusion were found to have a tongue-thrust dur
ing swallow but not during speech. Sixty per cent of the
subjects with malocclusion and defective speech thrust the
tongue during swallow. It was concluded that when the pro
trusive tongue habit was present, it was frequently, but not
always, associated with defective speech.
Ronson (1965) examined 60 lispers proportionately
selected from grades two, three, and four. Lateral lispers
were included as well as lingual protrusive and dental
lispers. It was found that 60 per cent of the second-grade
subjects, 55 per cent of the third-grade subjects, and 45
per cent of the fourth-grade subjects had visceral swallow.
It was concluded that the effect of visceral swallow correc
tion upon the prognosis of lisping needed to be determined.
Hackworth (1965) used cineradiography to investigate
ithe possibility that tongue-thrusters made inappropriate j
lingua-dental contacts during speech, but only the /t/
phoneme was tested. The sample consisted of 12 tongue- I
thrusting subjects, with an age range of 9 to 16 years, who
had acoustically normal speech. Of the total of 108 produc-
tions of /t/ for all subjects, only 11 were lingua-dental.
It was concluded that lingua-dental contacts occurred in a
tongue-thrust population but that the same variations would
occur in a non-thrusting population and that the infre
quency of the /t/ contacts would negate the theory that
detrimental effects upon occlusion would result.
Hedges, McLean, and Thompson (1965), in their inves
tigation of 22 children in grades six, seven, and eight used
cinefluorography to study the placement of the /t/, /0/, and
/$/ in sentences. All subjects had excellent occlusion and
acceptable speech, but it was found that some of the sub
jects were tongue-thrusters. It was suggested that because
the camera speed was 30 frames per second, all movements
were not seen. The lack of intersubject consistency in
tongue position during the phonation of any one of the dif
ferent sounds was surprising to the investigators. It was
concluded that many factors that were not originally consid
ered in the selection of the sample would account for some
of the variations but that the most probable cause of pho
neme variability appeared to be that of tongue morphology.
Opinions
Tulley (1965) noted that lisping speech occurred
when the tongue constantly rested against the lower lip in
swallowing.
According to Barber and Renfroe (1957) habitual
thrusting of the tongue between the anterior teeth would
occur in certain speech defects characterized by lisping but
would occur more frequently during swallowing.
Shelton, Haskins, and Bosnia (1959) studied tongue-
thrusting in a pair of monozygotic twins and concluded that
tongue-thrusting would cause lisping when it interfered with
tongue control during speech.
Palmer (1962) noted a sibilant difference in most
clients who subsequently showed marked tongue-thrusting
problems. The sibilant difference occurred predominately on
the /s/, although other articulation differences such as
dentalization of /t/, /d/, and /n/, and something akin to
the dark /l/ were sometimes noticed. It was concluded that
tongue-thrusting was importantly related to speech.
Summary
The literature presented evidence that there was a
strong relationship between tongue-thrust swallow and speech
defects, particularly the sibilants and more specifically
the /s/ and /z/ phonemes. There was some evidence to sup
port the opinion that tongue-thrust swallow and sibilant
distortion in subjects without a tongue-thrust swallow were ;
statistically related to age. No evidence was found which
indicated a significant relationship between age and sibi
lant distortion in subjects with a tongue-thrust swallow.
Tongue-Thrust Swallow and Malocclusion
Research
Rogers (1961) studied 497 orthodontic patients to
determine the number who had abnormal movements of the
tongue and/or facial muscles during swallowing and to com
pare the percentage of incidence with an elementary school
sample of 290 children. The elementary school children were
younger than the orthodontic patients, but exact age differ
ences were not noted. Results showed that 62.8 per cent of
the orthodontic patients exhibited a swallowing abnormality
compared to 56.9 per cent of the school subjects. No ortho
dontic treatment was needed by 112 of the school children,
and 92 of those children needing no orthodontic treatment
had normal swallow. Rogers' opinion was that the observed
relationship of swallow to malocclusion substantiated the
theory that improper swallowing does disturb tooth position
and normal dentofacial growth. The types of occlusion in
both groups showing a high coincidence with tongue-thrust
during deglutition were deep overbite, Class II deep over
bite, and open bite. It was suggested that improved tooth
position resulting from orthodontic changes had eliminated
the perverted swallowing in cases that were near completion
of orthodontic treatment and in which the overbite and open
........ . 24
! !
bite had been corrected.
Ward, Malone, Jann, and Jann (1961) examined 358 j
children in grades one through three and found that maloc- j
elusion and visceral swallowing were coincidentally present ■
in 91 per cent of the subjects. However, as was previously
noted, speech clinicians examined occlusion and deglutition
of 259 of the children because of the high correlation of
the findings of the speech clinicians and a pedodontist at
the examination of the first 99 subjects.
Subtelny, Mestre, and Subtelny (1964) found that 42
per cent of their 48 subjects with malocclusion manifested
tongue-thrust swallow.
The result of Ronson's investigation of 60 lispers
(1965) revealed that 75 per cent of the second-grade chil
dren, 73 per cent of the third-grade children, and 89 per
cent of the fourth-grade children showed both visceral swal
low and malocclusion. The number of normal swallowers with
malocclusion was none in the second grade, 33 per cent in
the third grade, and 27 per cent in the fourth grade.
Ronson concluded that most normal swallowers examined had no
malocclusions and that most visceral swallowers did have
malocclusions.
Opinions
Gwynne-Evans (1952) cited Rix to be the first
observer to point out that a number of dental abnormalities
seemed to be related to persistent infantile patterns of
.......................................................... 2 5 i
i :
swallowing behavior. Gwynne-Evans stated that the shape of
i
the dental arches and the alignment of the teeth generally,
corresponded to and fit in with the pattern of orofacial
behavior in feeding and in swallowing.
According to Brodie (1950) the tongue musculature
and the buccinator musculature comprised the first orthodon
tic force to operate on the teeth, and the muscular force
continued throughout life. The direction of alveolar growth
and the eruption of teeth were strongly influenced by the
tensions of these two muscle groups.
Swinehart (1950) voiced an opinion similar to that
of Brodie. The alveolar process was recognized as a bone of
adaption. From the time of the eruption of the teeth, the
environmental muscular forces became important factors in
the development of arch form. Therefore, it was logical to
believe that the forces of the tongue were largely respon
sible for maintaining or altering arch form.
A conflicting viewpoint to that of Brodie and Swine
hart was advanced by Scott (1957), who noted that deviations
in dental arch form were due to the nature of alveolar
process growth. According to Scott, the arch form was
determined before tooth eruption and depended for its final
development on the direction and extent of alveolar process
growth that was minimally effected by soft tissue.
Rix (1953) listed types of malocclusions that would
possibly result when infantile or "suckling swallow" was
retained. He also listed types of dental deformities
resulting from the tooth-apart swallow even though the swal
lowing pattern had lost its essential suckling characteris
tic .
Moyers (1958) cited tongue-thrusting as one of the
causes of malocclusion; and Tulley (1956) was also of the
opinion that behavior of the lower lip and tongue would pos
sibly be primary and not secondary to the causes of maloc
clusion.
Krogman (19 58) was ambivalent on the question of the
relationship between oral habits and malocclusion. It was
his opinion that oral habits were overrated as causative
factors, although they would possibly make dentofacial dys
plasias worse if there were a predisposition to such dyspla
sias. He concluded that oral habits must be severe and
prolonged to distort an otherwise acceptable dentofacial
complex.
Shelton, Haskins, and Bosma (1959) offered the opin
ion that tongue-thrusting would cause, malocclusion when it
affected tongue placement in swallowing or at rest. Bosma
(1963) later commented that he and his colleagues were at
the stage of merely describing the aberrations of motor
function that were found in cases of oral-area deformity,
rather than indicating the motor aberrations as causing the
abnormalities.
Jann (1960) was of the opinion that perverted swal-
; .......................... 27
lowing and tongue-thrust habits had a direct causal rela- ;
I ' :
tionship with the open bite type of malocclusion.
Strang and Thompson (1958) stressed the importance
of tongue-thrust swallow and the accompanying excessive lip
action not only in changing tooth alignment but also in pre
venting the molding of the denture into its normal size and
shape. Strang and Thompson suggested that the forces of
perverted muscular action were stronger than the normal
developmental forces of the denture and that they overpow
ered the latter so that they were unable to evolve normal
arch form and proper occlusion of the teeth.
Timms (1965) promoted the cybernetic concept of oro
facial behavior and maintained that it was the basic morpho
logical characteristics of soft tissue elements and their
relationships to adjacent structures which were of prime
importance, with behavior largely subservient to the mor
phology, given a healthy neuromuscular background. The term
"abnormal function" was associated with conditions of nerve
and muscle pathologies. Apparent differences in behavior
patterns between individuals for a similar function were,
therefore, a result of the differing morphology, not the
differing physiology.
Subtelny (1965) acknowledged that abnormal muscle
action would deform bone, but he advised that it was impor
tant to differentiate abnormal muscle behavior from varia
tions of normal behavior. Cleall's study (1965) supported
I “ ..“ .....~ ......................... 28
i |
Subtelny's opinion of the importance of differentiating ‘
abnormal muscle behavior from variations of normal behavior.;
Subtelny and Sakuda (1966) suggested that tongue-thrust was :
an associated factor of malocclusion rather than a causative
factor and that tongue-thrust should be considered in rela
tion to age, because age would possibly be a maturational
factor.
Summary
Evidence from the literature supported the opinion
of a relatively high coincidence of tongue-thrust swallow
and malocclusion. The question of etiology in the rela
tionship between tongue-thrust and malocclusion is a highly
controversial one. The most recent research pertains to
when and whether tongue-thrust is abnormal, whether or not
it will adapt to changed oral structure as a result of
orthodontic treatment, and whether or not it will adapt to
changed oral structure as a result of maturational forces.
Speech Defects and Malocclusion
Research
Carrell (1936) investigated a school population of
1174 children ranging in age from 5 to 18 years. Sixty-one
children were found to have sound substitutions and lisping
and were compared with normally speaking children on the
basis of age, sex, intelligence, and approximate grade
placement. Both the experimental group and the control
29
group were examined by a dentist and notations were made
concerning: palatal shape, frenum length, overbite, under
bite, interproximal spaces, and missing teeth. The results
showed no marked differences between the experimental and
the control groups, but the speech defective group had
slightly more cases with wide interproximal spaces (more
than 2 millimeters) in the anterior regions and more missing
teeth than the control group. To test the hypothesis that
dental abnormalities which caused an opening in the closed
bite in any specific region were associated with sound sub
stitutions, any condition which would cause an opening in
the closed bite was considered according to the location of
the teeth: anterior, lateral, and posterior regions of each
half of both the upper and lower jaws. Missing teeth, over
bite, underbite, wide interproximal spaces, and rotated and
partially erupted teeth were among the conditions consid
ered. Results showed that there were no marked differences
between the defective speech group and the non-defective
speech group as far as the frequency of openings in any
region was concerned. It was concluded that there was no
apparent relationship between dental conditions and the
severity of the speech defect but that defective dentition
would be of etiological significance in some relatively
infrequent speech disorders.
The results obtained by Carrell (1936) differed from
those of Fymbo (1936), who reported a study involving
30
detailed oral and speech examinations of 410 university stu
dents. Speech clinicians classified 111 students into a
defective speech group and 100 students into a superior
speech group. The group in average speech ability consisted
of a random sample of 199 students. Students who presented
minor rotations and misalignments of the teeth and very
slight mesial and distal discrepancies of the arches were
classified as having slight malocclusion. The students with
serious anomalies in the formation of the dental arches and
in the relation of one arch to the other were classified as
having severe malocclusion. The students with malocclusion
severe enough to result in an unpleasing contour of the face
were classified as havirig facial deformity. Approximately
87 per cent of the 111 subjects in the speech defective
group had malocclusion, but only 35 per cent of the superior
speech group had malocclusion. Sixty-two per cent of the
199 subjects in the average speech group had malocclusion.
There was a progressive decrease in dental anomalies when
the defective speech group was compared with the superior
speech group. The total samples was regrouped on the basis
of normal occlusion and malocclusion, and the relationship
between malocclusion and difficulty with specific speech
sounds was determined. The /s/ and /z/ phonemes presented
the most difficulty for both the normal occlusion group and
the malocclusion group. Approximately 43 per cent of the
146 subjects with normal occlusion had difficulty with /s/,
land 35.06 per cent had difficulty with /z/. Approximately
i
64 per cent of the 264 subjects with malocclusion had diffi
culty with /z/. The malocclusion group showed a higher
incidence of difficulty with the other so-called dental
sounds (/0/, /%/, ///, /%/> /t/A and /d^/) than with the
other consonants. It was concluded that because the sub
jects with malocclusion had more difficulty with the dental
sounds than did the subjects with normal occlusion and that
because the two groups did not differ in regard to other
sounds, the condition of occlusion was vitally related to
the formation of certain speech sounds.
Frowine and Moser (1944) observed over a period of
two years the speech of seven children with a broad range of
dentofacial anomalies. The subjects ranged in age from 7 to
16 years. A detailed description of each subject was given,
including dental and speech analysis. The speech of each
subject was rated excellent, satisfactory, or unsatisfac
tory. Three subjects presented severe dentofacial deformity
but satisfactory speech with no help from speech training.
Two subjects had malpositioned teeth but satisfactory
speech. The speech of one subject was rated excellent, and
the speech of only one subject was considered to be unsatis
factory. It was concluded that although the sample was
small, the study showed a definite tendency toward compensa
tion for dentofacial anomalies.
Fairbanks and Lintner (1951), conducted an investi-
gation for the purpose of studying the relationship of oral
structure to functional disorders of articulation in 1250
college students. The subjects were screened for speech
defects and rated on a seven-point scale. Five was the
lower limit of the superior group, and three was the upper
limit for the inferior group. Subjects identified by the
preliminary screening were called in at random for a direct
test of consonant production judged by two speech clini
cians. Sixty experimental subjects were chosen: 30 with
superior consonant articulation and 30 with inferior conso
nant articulation. The teeth of the subjects were examined
and judged in four general respects:
(1) Molar occlusion according to Angle;
(2) Occlusion of the upper and lower anterior teeth in
both antero-posterior and infero-superior planes;
(3) Alignment of the individual upper and lower incisors
and bicuspids;
(4) Spaces (failures of proximal contact) anterior to
the bicuspids, both upper and lower.
Each item was rated on a normal-slight-marked deviation
scale. The inferior group had more deviations in molar oc
clusion, but the differences were not statistically signifi
cant. Anterior occlusion was more deviate in the inferior
speech group, but the results were not statistically signif
icant. The sixty subjects were then divided into two dental
categories: (1) normal or only slight deviations in all
four of the general items and (2) one or more marked devia
tions. Those subjects with overjet or undershot conditions
33
did not differ significantly in superior or inferior speech,
but open or closed bite was significantly (at the ,01 level)
more numerous in subjects having inferior speech, with open
bite the greater factor in the difference. It was concluded
that marked dental deviations were more numerous among indi
viduals with so-called "functional" disorders of consonant
articulation than among those with superior articulation.
Bernstein (1954) investigated the incidence of mal
occlusion existing in 437 children with speech defects and
in 446 children with normal speech. After completion of the
orthodontic examinations, the experimental speech group was
divided into two subgroups: defective speech with malocclu
sion and defective speech without malocclusion. The sub
jects with speech defects and malocclusion were given
lateral head x-rays and speech recordings. The following
findings were reported:
(1) Malocclusion was not more prevalent in children who
have speech defects;
(2) Speech defects were not generally related to maloc
clusion except in cases of open bite;
(3) There was a strong relationship between open bite
and lisping;
(4) The severity of the lisp in open bite cases did not
vary with the amount of opening, the amount of over
jet, or the amount of overbite.
Benediktsson (1959) used roentgenography to investi
gate the relations of the tongue and the jaws during /s/
sound production in cases with normal and abnormal incisal
occlusion. The sample consisted of 246 patients. Subjects
with abnormal incisal occlusion were divided into nine
groups according to combinations of overbite and overjet.
The subjects with normal occlusion served as controls. All
subjects were x-rayed with the teeth in occlusion, with the
jaws at rest, and during /s/ production. Benediktsson con
cluded that it was conceivable that certain speech anomalies
were caused by failure of functional adaptation due to
(1) lack of ability to adapt or to (2) too extreme devia
tions from normal incisal occlusion.
Rathbone and Snidecor (1959), an orthodontist and a
speech pathologist, studied ten orthodontic patients prior
to treatment. All patients had highly defective speech.
The original purpose of the inquiry was to appraise the
effectiveness of the orthodontist in evaluating speech
defects. The study was expanded to include the prediction
of speech defects from models alone, the relation of the
severity of the malocclusion to the severity of the speech
defect, and the reappraisal of the speech defect following
orthodontic treatment without speech correction. The ortho
dontist rated the severity of the malocclusion, and the
speech pathologist rated the severity of the speech defect.
Results showed that the two examiners agreed 91.4 per cent
on rating the more common dental fricative sounds (/s/, ///,
/z/, and /$/), but their agreement on the other 12 sounds
was 51.3 per cent, which they attributed to the orthodon
tist's lack of speech training. Results also showed that
there was no one-to-one relationship between the severity of;
the malocclusion and the severity of the speech defect and
that models alone were insufficient to judge accurately the
production of dental sounds. Four years later eight of the
ten patients had completed orthodontia and were available
for administration of the same test sentences used previ
ously in judging speech. Whereas the mean number of defec
tive sounds for the 8 subjects of the original group was 6.4
of the 16 sounds, it was only 1.5 defective sounds after the
teeth had been corrected. The residual errors still
observed were the highly noticeable fricatives (/s/, /z/,
///, /^/, /0/, and /%/) but to a lesser degree quantitative
ly and qualitatively. It was concluded that, generally,
improved structural factors predict improvements in speech
with residual errors that can be reduced or eliminated
through speech therapy.
Snow (1961) examined the articulation of 438 first-
grade children for the purpose of comparing the production
of /f/, /v/, /0/, /#/, /s/, and /z/ of children whose inci
sor teeth were present with a group of children whose teeth
were missing or grossly abnormal. The 99 children with
missing or grossly malpositioned teeth made a total of 3562
responses on the six sounds, and the 339 children without
such dental problems made a total of 15,738 responses to the
same test items. Percentages were computed, and the differ
ence between the two groups was tested by use of a
36
nonparametric test. The children with missing or abnormal
upper central incisors made significantly more errors on the
sounds tested. However, the investigator emphasized the
fact that most of the children with defective teeth made the
sounds correctly and that some of the children, with normal
teeth did not make the sounds correctly. It was concluded
that the results of the study indicated the likelihood that
the condition of the teeth was for some few children a cru
cial factor in the development of correct articulation.
Opinions
It was the opinion of Wepman (1937) that misarticu-
lations of the sibilants were most frequently due to faulty
dentition, either now present or existing during some
earlier period when the bad habit was formed. Bloomer
(1957) listed dental classifications and types of speech
problems which would possibly be associated with them,
although he emphasized that abnormalities of orofacial
structure could not themselves alone be considered as prime
causes of defective articulation. Ballard (1963) was of the
opinion that in Class II, Division 1 cases there would
possibly be an interdental sigmatism because the tip of the
tongue during the articulation persisted in coming between
the teeth in order to seal off the overjet space.
Strang and Thompson (1958) suggested that when the
anterior end of the tongue was held in contact with the
occlusal edges of the incisors, as in lisping, and the
mandible was maintained more or less stationary, the result I
j i
was a labial deflection of the incisors or infraocclusion of;
; I
these teeth. Graber (1966) minimized the probability of j
jtooth misalignment caused by faulty speech production but he;
cautioned that the possibility should not be overlooked.
Harrington and Breinholt (1963) commented that the
serious speech defects that sometimes existed as a part of
the oral-mechanism syndrome would possibly contribute to the
seriousness of the orthodontic problem.
Schurter (1962) stated that certain techniques used
to correct lisping resulted in tooth misalignment.
Summary
A review of the literature revealed no agreement
between the relationship of speech defects and malocclusion.
There was some agreement that sibilant distortion was coin
cidental with some types of malocclusions.
CHAPTER III
METHODS AND PROCEDURES
Research Design
This study was designed to investigate the follow
ing: (1) the effect of deglutition training on dental over
jet, (2) the effect of a particular type of sigmatism train
ing on dental overjet, and (3) the difference between the
effect of deglutition training and the effect of the partic
ular type of sigmatism training on dental overjet. The
independent variables were correction of the pattern of
deglutition and correction of sigmatism. The dependent
variable was the measurement of the dental overjet.
The sample consisted of 58 subjects who exhibited
tongue-thrust swallow, sigmatism, and an estimated overjet
of at least four millimeters. Eighteen subjects (Experi
mental Group D) were given only deglutition training, 16
subjects (Experimental Group S) were given only sigmatism
training, and 18 subjects (Control Group C) received no
training. The 16 experimental speech subjects were matched
with 16 experimental deglutition subjects and 16 control
subjects. The sample initially consisted of 18 subjects in
each group, but 2 experimental speech subjects did not com-
38
..........39
plete training. Six additional subjects (Experimental Group
LM-Lip and Mouth) could not be matched on the basis of sex
and age and were given semi-training in order to determine
whether or not lip exercises and keeping the mouth closed
would decrease the overjet without deglutition or speech
training.
No training was initiated until each subject had a
dental impression and a lateral occlusal head film made and
was recorded reading a passage containing 9 /s/ and 9 /z/
phonemes. When one experimental subject reached a criterion
level of correction, he continued intensive training until
his match in the other experimental group reached his crite
rion level of correction. At that time both experimental
subjects and their control had interim dental impressions
and interim lateral occlusal head films made, and the expe
rimental speech subject made an interim recording of a dif
ferent passage containing 9 /s/ and 9 /z/ phonemes. Each
trio waited a period of 3 months, and during that time the
experimental subjects received only minimal training to
assure entrenchment of correction. At the termination of
the waiting period each trio had post-test dental impres
sions, post-test lateral occlusal head films made; and the
experimental speech subject made his post-test recording of
a still different passage containing 9 /s/ and 9 /z/ pho
nemes.
Training thus consisted of two phases: (1) inten-
: .......... 40
sive, until correction was achieved for both matched experi
mental subjects and (2) minimal, for a period of 3 months
following intensive training. A system of positive rein
forcement was developed to encourage the performance of
assigned tasks. Measurement and evaluation procedures were
conducted at 3 different times: (1) pre-test, before any
training was initiated; (2) interim, when each pair of
matched experimental subjects attained deglutition or speech
criterion level of correction; and (3) post-test, at the
termination of the three-month waiting period. The timing
for conducting interim and post-test measurements and
evaluations for each subject in Group LM was established to
approximate that of the matched trio of the same sex and
whose age span most nearly corresponded with the age of the
unmatched subject. It should be emphasized here that only
pre- and post-test head films were necessary to compute and
compare the effect of deglutition correction and the effect
of speech correction on dental overjet. Other pre- and
post-tests and interim tests were utilized as checks for
(1) subject variation in sigmatism (pre-test tape record
ings) , (2) for attainment of correction criteria (interim
tape recordings), (3) progress (interim head films),
(4) accuracy of orthodontic opinions concerning occlusion
(dental impressions), and (5) accuracy in tracing the head
films (dental impressions).
The speech tapes were evaluated, and the number of
/s/ and /z/ errors was tabulated for all subjects on the
pre-test recording and for the experimental speech subjects
on the interim and post-test recordings. The head films
were traced, and the amounts of the dental overjets were
computed. A method was devised to distinguish changes that
had occurred in the overjet as a result of growth from those
changes that had occurred as a result of training. The
post-test overjet measurement was adjusted to indicate only
the result of training or adverse muscular pressure, and the
mean differences between pre- and post-test measurements
were compared within the two experimental groups and among
the three matched groups.
Operational Definitions of Terms Used
Dental Overjet: The linear measurement of the dis
tance from one-half the thickness of the x-ray profile of
the cutting edge of the maxillary incisors to one-half the
thickness of the profile of the cutting edge of the mandibu
lar incisors (as suggested by Steadman, 1949).
Adjusted Dental Overjet: The measurement of the
post-test overjet after the effect of training and the
effect of deleterious lingual pressure on the incisors had
been distinguished from other forces, including growth, that
would affect the incisors. A linear measurement was made on
the tracing of the post-test x-ray in the same manner as
was done on the pre-test x-ray, and this figure remained
the final post-test overjet measurement if the distance
between the midpoint of the cutting edge of the mandibular
incisors to Point A had not changed (see Figure 1, page 61).
The pre- and post-test difference between Point A and the
midpoint of the maxillary incisors was assumed to reflect
the effect of training or of deleterious muscular pressure.
Both speech training and deglutition training were designed
to affect the maxillary incisors. The assumption that the
mandibular incisors were not affected by training is based
on the fact that there was no pre- and post-test difference
in the inclination of the mandibular incisors among the
three groups (the group that received no training and the
two experimental groups). (See Appendix H.) For the sub
jects concerned in this study, the changes in the distance
from the midpoint of the mandibular incisors to Point A
reflected changes, possibly concerned with growth, that were
not due to training or to deleterious effects of lingual
muscular pressure upon the incisors. Therefore, the formula
for deriving the adjusted dental overjet was as follows: If
the distance between the midpoint of the mandibular incisors
to Point A had decreased, the amount of the decrease was
added to the actual overjet measurement because factors
other than training accounted for the decrease. If the dis
tance from the midpoint of the mandibular incisors to Point
A had increased, the increase was subtracted from the actual
overjet measurement because factors other than deleterious
effects of lingual muscular pressure were responsible for
..................43
' i
the apparent increase in the overjet.
Sigmatism; Defects of /s/ and /z/. According to
Carrell (1968) the term "sigmatism" has sometimes been used
as a synonym for lisping, but it is more properly applied to
/s/ defects. Because the production of /z/ is the same as
that for /s/ except for the addition of voicing and slightly
less forceful articulation (Carrell and Tiffany, 1960), in
this study the term "sigmatism" was used to include both the
defective /s/ and the defective /z/.
Presence of Sigmatism: More than 2 of the 9 /s/ and
more than 2 of the 9 /z/ phonemes of a recorded passage must
be judged defective by all 3 of a panel of trained speech
clinicians. In subject selection a distinction was made
between frontal and lateral sigmatism. The subjects were
originally selected on agreement of the investigator and one
other speech clinician that the tongue was excessively
"fronted" (Subtelny, Mestre, and Subtelny, 1964), that the
tongue touched the incisors either dentally or interdentally
during /s/ and /z/ production, and that the sound was acous
tically defective. However, because judges (who had had no
part in the original selection of subjects) made their rat
ings from recorded speech only, no real distinction can be
made between frontal and lateral sigmatism.
Sigmatism Training: Training to correct the defec
tive /s/ and /z/.
Correction Criteria of Sigmatism: No more than 2 of
the 9 /s/ and no more than 2 of the 9 /z/ phonemes of any 1
of the 3 recorded reading passages must be judged defective
by any 1 of the 3 judges.
Tongue-Thrust Swallow; Anatomical indications of
lingual pressure on the incisors plus actual observation of
pressure of the tongue on the incisors both during swallow
of saliva and swallow of water. The opinions of 2 orthodon
tists, who independently examined subjects, that the re
quirements of the definition were met were necessary for
determination of the presence of tongue-thrust swallow.
Although perioral action and lack of masseter action were
not required for determination of the presence of tongue-
thrust swallow, all subjects, referred to the orthodontists
exhibited, in the opinion of the investigator, some degree
of perioral action and little or no masseter action. (Peri
oral action is visible movement of the muscles of facial
expression, particularly around the mouth. Lack of masseter
action usually indicates an open-tooth swallow.)
Deglutition Training (Swallow Training); Training
to correct tongue-thrust swallow.
Correction Criteria of Deglutition (the act of
swallowing): Three consecutive thirty-minute training ses
sions in which masseter action, no perioral action, and no
visible lingua-dental contact during swallow could be
observed by the investigator, or the assisting clinician, or
any competing subject in the particular experimental group. ;
45
System of Positive Reinforcement; Rewarding sub
jects for completing training assignments, for performing
extra assignments in competition with other subjects, and
for noting errors made by other subjects.
Subject Criteria
The Sample
The sample initially consisted of 61 subjects (3
subjects did not complete the project) who met the following
requirements:
1. At least nine years and five months and no more than
thirteen years and eleven months of age
2. The presence of sigmatism
3. Two orthodontic opinions that
(a) a frontal tongue-thrust was present
(b) the molar relationship was either Angle's Class
I or Class II
(c) there was an estimated overjet of at least four
millimeters or more
(d) there was absence of any tooth crowding that
would prevent any subject having an equal chance
for overjet improvement
(e) there was absence of enlarged tonsils and ade
noids (see Appendix A for form used by the
orthodontists)
4. No orofacial operations with the exception of ton
sillectomies and adenoidectomies and tooth
! extractions !
; i
i j
; 5. No orthodontic treatment !
• |
i 6. Normal intelligence (determined by examination of
! school records)
7. Normal hearing (determined by pure-tone audiometric
t ;
testing administered by the school nurses)
8. Absence of chronic nasal infection or allergy
(determined by a case history form completed by one
of the parents— Appendix B)
9. History of regular school attendance
10. Written consent of the parents for the necessary
procedures to be used in evaluation and measure
ment.
Obtaining the Sample
All 5th, 6th, 7th, 8th, 9th, and some 4th grades in
the public schools in a city of 85,000 population were
screened for Caucasian children with sigmatism and an esti
mated overjet of four millimeters. Grades four and nine
were found generally not to represent the ages required, but
6139 children were screened in grades five through eight.
Two hundred fifty-four children of the 6139 children
screened, plus some fourth-grade children, were listed as
possible candidates for the study and were individually
examined by two speech clinicians, the investigator and the
regularly scheduled clinician in each subject's particular
school. It was the opinion of the examiners that 72
.........47
; i
children met the first nine of the subject criteria. Eight j
children were eliminated because of change of residence or
failure to obtain parental consent. Sixty-four possible
subjects were examined by the orthodontists; but three of
the subjects failed to meet the orthodontic criteria, two
children because of tooth crowding and one child because of
lack of a thrust. The study began with 17 males with a mean
age of 11.5 years and 44 females with a mean age of 11.25
years. Three subjects, one male and two females, did not
complete the project.
Assignment of Subjects
into Groups
The following criteria were established in order for
a school to be eligible for one or more training classes:
1. A regular school speech clinician scheduled twice
weekly
2. At least four eligible subjects
Twenty-five schools scattered throughout the city were
involved in the project, and only by establishing the two
requirements was it possible for the experimental subjects
to be seen four times weekly, twice by the investigator and
twice by the regularly scheduled school speech clinician.
An attempt was made to utilize as many eligible
school subjects as possible in the experimental classes.
Each subject in the eligible schools was interviewed by the
investigator and the school clinician. Each child was told :
................48]
that if, by chance, he were chosen to receive training, he j
would be required to be out of his classroom four times
weekly. He would be expected to work diligently, but he
would be rewarded for it. The system of positive reinforce
ment was explained to him: he would have the opportunity to
choose the reward, and the size of the reward would be com
mensurate with the amount of his work. If the child did not
wish the opportunity to be chosen for training, he would
receive smaller rewards for brushing his teeth in competi
tion with the other controls. Six of the subjects declined
training but agreed that they would be willing to brush
their teeth for reward.
Sex and age were considered to be the most important
factors in matching because of the difference in growth rate
between the sexes and the growth variability of the particu
lar age span (Baum, 1951, 1961, 1966; Johnston, Hufham,
Moreschi, and Terry, 1965; and Hunter, 1966). Angle's
classification was considered to be of secondary importance
because it was subject to change with growth in the particu
lar age span. Also, Angle's classification assumed a cer
tain normal antero-posterior relationship of the jaws to
each other with the mesiobuccal cusp of the maxillary first
permanent molar occluding in the buccal groove of the first
permanent mandibular molar (Bloomer, 1957). Therefore,
molar classification alone would not describe true occlu
sion.
49;
: i
The seven subjects in eligible schools who had had
previous speech training were automatically assigned to the
experimental speech group, and the one subject in an eli
gible school who had had deglutition training was assigned
to the experimental deglutition group. The preceding
assignments were made in order to minimize the possibility
of any improvement as a result of any type of training other
than the experimental training. The remaining subjects in
eligible schools were randomly assigned to the two experi
mental groups by use of a table of random numbers (Kendall
and Smith, 1939) with the exception of one subject who could
not be matched. The 6 subjects who did not want training
and the subjects in ineligible schools were matched as con
trols as nearly as possible with the experimental subjects
with the exception of five subjects who could not be
matched. Table 1 presents the three major groups and the
data upon which the subjects were matched. All subjects
were matched on the basis of sex, and all but the first
three trios were within one year of the same age. The trio
with the greatest age difference was number 3 with a span of
almost fifteen months. Pour trios could not be matched on
Angle's classification. Six control subjects had had previ
ous speech training, and one control subject had had previ
ous deglutition training.
Materials and Apparatus
Three different reading passages (I, II, and III)
ib ji
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
TABLE 1
The Three Matched Groups: Sex, Age, and Angle's Classification
Speech Training Deglutition Training Control
Sex Birthdate Angle Class Subject Sex Birthdate Angle Class Subject Sex Birthdate Angle Class
II 1 M M 9/24/57 II
F 5/12/58 II Sub
F 4/6/57 II
F 3/18/56 II Sub
F 7/12/56 II Sub
F 11/7/57 II Sub
F 11/6/54 II
M 12/10/54 I
F 5/7/58 II Sub
F 6/7/56 I
M 9/7/57 I
M 11/1/57 II
F 7/10/58 II
F 7/16/55 II
F 2/21/54 I
F 7/13/55 I
1 M 10/2/56
2 F 9/17/57
3 F 1/11/56
4 . F 1/19/57
5 F 5/14/56
6 F 11/24/57
7 F 6/30/55
8 M 6/21/55
9 F 9/19/57
10 F 5/31/56
11 M 7/31/57
12 M 2/22/58
13 F 4/13/58
14 F 4/5/56
15 F 6/15/54
16 F 9/13/54
17 F 2/12/55
18 F 11/19/55
II 2 F
II 3 F
I 4 F
I 5 F
II 6 F
II 7 F
I 8 M
II Sub L 9 F
II Sub R 10 F
I ■ 11 M
II 12 M
II 13 F
II 14 F
II 15 F
I 16 F
I 17 F
I 18 F
8/18/56 II Sub R
4/29/57 II
10/2/56 II
9/4/56 II
7/23/56 I
4/25/57 II
5/10/55 II
10/30/54 I
7/30/57 II Sub R
5/27/56 I
11/30/57 ' I
5/10/57 II
2/15/58 I
8/3/55 II Sub R
10/9/54 II
4/14/54 I
5/24/55 I
2/10/56 I
Were composed for the purpose of judging 9 /s/ phonemes and
9 /z/ phonemes either good or defective. (See Appendix C.)
Passages were printed on 9" x 12" tagboards and were chosen
by chance by the subjects reaching behind themselves. The
experimental speech group recorded all three passages.
Thus, for the experimental speech group each recording elim
inated one choice; and no passage was repeated by any sub
ject. An analysis of variance was utilized on the results
of the pre-test recording, in which all subjects partici
pated, to test the hypothesis that the three passages were
of equal difficulty. The obtained F value of 0.14 with 2
and 55 degrees of freedom was not significant; and, thus,
the assumption was made that the passages were of equal dif
ficulty. (See Appendix D.)
Code numbers for subject identification were printed
on 1" x 2" cards which the subjects chose from the blank
side. Each subject read his code number and the passage
aloud one time before recording. The experimenter main
tained the microphone approximately twelve inches from the
mouth of the speaker. The passages were recorded on mag
netic tape through an Ampex 602 Professional tape recorder
and matched 611 microphone. The recording playback was
heard through an Ampex 622 Speaker-Amplifier. The recorder
head was cleaned before each taping and listening session.
All recordings and playbacks for judging were completed in
the same sound-treated room with the equipment in the same
52
position each time. Only the experimenter and the subject
were present during the recording.
Roentgenographic Cephalometry
The 174 x-rays were made in the same professional
setting (Donald W. McCormack, Jr., Dental X-Ray Laboratory).
The machine used was a Profexray 100 MA with a Eureka rota
ting anode tube. A Wehmer Cephalometer was used to position
the head. The occlusal film (Eastman Kodak BB-54) was made
at 80 kv with an exposure time of one-half second. The dis
tance of the target to subject was 60 inches, and the dis
tance of subject to film was 130 millimeters.
Dental Impressions
Four practicing orthodontists in the Pomona-Clare-
mont area made the dental impressions with the usual
Alginate. Four to six subjects were scheduled for each
appointment, and the trays containing the impressions were
immediately taken by the investigator to the laboratory.
The same two technicians cast and finished all of the 174
models.
Training
A project kit was maintained in each training school
during the entire period. The kit contained paper cups,
tongue blades, sugarless wafers, "point chips" for reward,
and a notebook. The notebook provided a separate section
for each subject in his particular school, and in it was
recorded each date a subject was seen, what phase of train- j
i i
ing was conducted, the progress of the subject, and possible;
suggestions for the next session. The use of this notebook j
provided the investigator and the school speech clinician
close contact on both training procedures and the progress
of each subject.
Procedures
Before any training was initiated, each subject was
recorded reading one of the three passages, dental impres
sions were taken, and a lateral head film was made with the
teeth in occlusion.
Training was conducted by the investigator and five
public school speech clinicians in the particular schools
that the subjects attended. Until interim measurement pro
cedures were conducted, subjects in the speech and degluti
tion groups were scheduled four times weekly, either indi
vidually or in groups. The subjects who could not be
matched were scheduled once each week, and the control sub
jects were scheduled once every two weeks. Only the inves
tigator met with the controls and the subjects who could not
be matched.
When the criterion level of correction was achieved
by one of the subjects in either training group, the subject
continued to receive intensive training until his match in
the other experimental group attained his criterion level of
correction. When both experimental subjects reached cor
rection criteria, the matched experimental subjects and
their control had interim dental impressions and interim
occlusal films made; and the experimental speech subject
made his second recording. Interim procedures for the sub
jects who could not be matched were timed to approximate
those of the matched trio of the same sex who were closest
to them in age.
After interim proceedings the experimental subjects
were seen once each week for approximately three months in
order to assure entrenchment of training. Control subjects
and subjects who could not be matched followed their regular
schedules. When the waiting periods were completed, post
test proceedings were initiated. Training time ranged from
four to six months with a mean of five and one-fourth
months.
Speech Training
Speech training began with tongue control and aware
ness of tongue position. If a tongue deviation to either
side was present, resistance exercises were initiated to
correct the deviation. The first emphasis in phoneme place
ment was centered upon lingua-alveolar contact for /t/, /d/,
/l/, and /n/. When production of these sounds became pro
ficient, the teaching of /s/ and /z/ placement began by
using as a starting point the final sound of a word ending
with one of the four lingua-alveolar sounds. With the sides
:of the tongue in contact with the upper alveolar ridge and
the tensed tip out of contact only enough to allow a small
emission of air, the /s/ and /z/ were produced. When /s/
and /z/ in the final position had been mastered, training
was extended to the initial position with the use of the
lingua-alveolar /t/ to obtain placement (Jann and Whitman,
19 63). As the subjects became proficient in producing the
initial /s/ and /z/ without the crutch of using /t/, empha
sis turned to acoustical quality of /s/ and /z/ in the
medial position. The subjects were urged to wear a plastic
mouthpiece (see diagram. Appendix E) as much as possible to
encourage nose breathing, to prevent wedging of the lower
lip against the upper incisors, and to create a gentle lip
pressure lingually against the upper incisors. The mouth
piece was an innovation of the investigator, but its purpose
was the same as other widely used deglutition training pro
cedures such as holding wax paper or circles of cardboard
between the lips or the use of an oral screen. Lip exer
cises (Appendix F) were also encouraged to produce lingual
pressure on the upper incisors. The mouthpiece and the lip
exercises were not originally a part of the speech tech
nique but were included in speech training in this study
because these two procedures were a part of deglutition
training. In order to compare the absence of tongue pres
sure upon the incisors during speech with the absence of
tongue pressure during deglutition and possibly at rest, the
same outside pressures exerted lingually against the maxil
lary incisors were made the same for the two experimental
groups. Although keeping the tongue away from the incisors
on all speech sounds except /0/ and />$/ was constantly
stressed to the experimental speech subjects, no referral to
lingua-dental contact during swallow or at rest was made.
When a subject progressed to the point at which the investi
gator and the assisting speech clinician agreed that the /s/
and /z/ phonemes were produced easily in conversation, the
subject was considered to be ready for his second recording.
Actual determination of correction was made by the judges
listening to the recording. The mean number of individual
training sessions was 8, and the mean number of group ses
sions was 35.0. The number of subjects seen in group ses
sions ranged from two to four.
Deglutition Training
The procedures used in deglutition training were
aimed at keeping the tongue in contact with the palate and
the tongue tip approximating the rugae and not contacting
the incisors both during swallow and at rest. Masseter
action and relaxation of the muscles of facial expression
during swallowing were stressed. The techniques used were
not unique to this study and were described in both speech
and dental publications (Ricketts, 1960; Harrington and
Breinholt, 1963; Wildman, Fletcher, and Gox, 1964; Hahn and
Sloan, 1966; and Jann, Whitmann, and Jann, 1966). However,
speech sounds were not used because of the nature of the
.......... 571
1
study and also because there was some doubt of the advisa
bility of such a practice (Wildman, Fletcher, and Cox,
1964) . in fact, no mention of lingua-dental contacts on :
speech sounds was made. Tongue and other muscle exercises
were performed as needed. The subjects performed the lip
exercises and wore the plastic mouthpiece in the same manner
as did the subjects in the experimental speech group. (See
Appendixes E and F.) Each subject attained the criterion
level of correction when his individual log indicated that
he had had three consecutive error-free training sessions of
thirty minutes each. The judgment of an error-free session
was the mutual agreement of the clinician present at the
time and the other experimental subjects in the group who
were rewarded for noting errors. The mean number of indi
vidual training sessions was 5, and the mean number of group
sessions was 35. The number of subjects seen in group ses
sions ranged from 2 to 4.
Lip and Mouth Exercises
The six subjects in Experiment Group LM wore the
plastic mouthpiece and performed the lip exercises in the
same manner as did the experimental speech and the experi
mental deglutition subjects. Although the number in the
group was small, the possibility existed that a change in
the dental overjet would result from a closed-mouth position
during rest and from labial pressure on the maxillary inci
sors resulting from the lip exercises. The number of
58
subjects seen in the sessions ranged from one to two. The
mean number of individual contacts was 5, and the mean num
ber of sessions with two subjects was 9.
Control Subjects
The control subjects recorded the number of times
they brushed their teeth. The score sheet was given to the
investigator every two weeks. The number of subjects seen
at one time ranged from 1 to 3. The mean number of individ
ual contacts was 6, and the mean number of group contacts
was 6.0.
System of Positive Reinforcement
The experimental subjects competed with each other
in their respective school training groups. Every two weeks
each subject was provided with a score sheet on which he
daily recorded the number of hours he wore his mouthpiece
and the number of lip exercises he performed. One point
each week was awarded for keeping the scores, one point for
the subject in each group who wore the mouthpiece the great
est number of hours, and one point for the subject who per
formed the greatest number of lip exercises. One point was
also awarded after each training session to the subject with
the best performance. Performance was usually based on the
total score obtained by each subject during the period. A
plus (+) was tabulated for a subject when he noted an error
made by another subject, and a minus (-) was tabulated for
the subject making the error. The total score was obtained
by subtracting the minuses from the plusses. In any case,
the subjects were instrumental in establishing the rules for
judging the best performance. Fractions of points were used
when necessary. Subjects were penalized one-half point for
being late for class, for having to be called for class, or
for not bringing their score sheets to each session. Points
were given in the form of paper chips which were kept in the
school research kit and were redeemed one day each week, or
were left for accumulation, when the investigator brought
the prize box. Items in the box ranged in value from one-
half point to over twenty points and were purchased by the
investigator according to the requests of the subjects.
The same point system was used for Experimental
Group LM with the exception that they did not have an oppor
tunity to accumulate training session points. They competed
in pairs, but both subjects were not matched and were not
necessarily in the same school.
The control subjects also competed in pairs. One
point was awarded for each week the score sheet was kept up
to date, and one point was awarded to the member of the pair
who brushed his teeth the greater number of times in the
two-week period.
Measurements, Speech
Five trained speech clinicians (A, B, C, D, and E)
rated as either good or defective the nine /s/ and the nine
r 59
the subject making the error. The total score was obtained
by subtracting the minuses from the plusses. In any case,
the subjects were instrumental in establishing the rules for;
judging the best performance. Fractions of points were used
when necessary. Subjects were penalized one-half point for
being late for class, for having to be called for class, or
for not bringing their score sheets to each session. Points
were given in the form of paper chips which were kept in the
school research kit and were redeemed one day each week, or
were left for accumulation, when the investigator brought
the prize box. Items in the box ranged in value from one-
half point to over twenty points and were purchased by the
investigator according to the requests of the subjects.
The same point system was used for Experimental
Group LM with the exception that they did not have an oppor
tunity to accumulate training session points. They competed
in pairs, but both subjects were not matched and were not
necessarily in the same school.
The control subjects also competed in pairs. One
point was awarded for each week the score sheet was kept up
to date, and one point was awarded to the member of the pair
who brushed his teeth the greater number of times in the
two-week period.
Measurements, Speech
Five trained speech clinicians (A, B, C, D, and E)
rated as either good or defective the nine /s/ and the nine
60
; 1
/z/ phonemes of 31 passages randomly selected (Kendall and
Smith, 1939) from the three tape recordings. (See Appendix
G for instructions to the judges.) Judges B, C, and E
showed the closest listener agreement and were then adminis
tered pure-tone audiometric tests by a community service
audiologist. The hearing of each judge was within normal
limits. Judges B, C, and E then judged all of the tape
recordings. Pearson's coefficient of correlation indicated
that the interjudge range was from .951 to .968. The aver
age interjudge agreement was .962.
Measurements, Overjet
The dental overjet was measured from the acetate
tracings of the pre- and post-test lateral head films with
the teeth in occlusion. Figure 1 illustrates the measure
ment: the distance from one-half the thickness of the pro
file of the cutting edge of the maxillary incisors to one-
half the thickness of the profile of the cutting edge of the
mandibular incisors. The tracing of the pre-test x-ray was
made in black and the tracing of the post-test x-ray was
made in red. The dot marking the midpoint of the incisal
profile was an arbitrary one, but it was kept the same for
each subject by superimposition of one acetate tracing over
the preceding tracing.
Figure 2 shows the points used in tracing. Explana
tion of the terms is provided in the glossary. For clarity,
the planes are shown separately in Figure 3. Figure 4 shows
2 mm
ii^tance from Point A
o- midpoint of maxillary
I I ^'^cisal profile
Female control subject
Age 11 yrs. 4 mos.
Date 11/20/67
_. % mm
Distance from midpoint
of mandibular incisal
profile to Point A
T'>- ^
^r~ — {Point A
Maxmlary incisal profile
Mandibular incisal profile
6. mm over jet
Distance from midpoint
of maxillary profile
to midpoint of
mandibular profile
Fig. 1.— Illustration of the measurement of the dental
overjet.
62
Go
■Po
Gn
Fig. 2.— Points utilized in tracing the head films.
63
Frankfort
Fig. 3.— Planes utilized in tracing the head films.
64
; I
all of the planes and angles traced. Many measurements were
not necessary in computing the dental overjet, but their
utilization was mandatory for the process of devising a
method by which the effect of growth upon the overjet could
be distinguished from the effect of training and the effort
of adverse muscular pressure.
Data Analysis
Development of a Method for
Distinguishing Training
Effects from Other Effects
Because the control subjects had had no training,
pre-test and post-test x-rays were completely traced (Figure
4) for one-half, or 9, of the controls, selected by a table
of random numbers (Kendall and Smith, 1939). Nine pre-test
and 9 post-test x-rays were considered to be a sufficient
number to indicate which changes in dental overjet were
related to factors other than training. Three changes that
showed the closest relations to changes in dental overjet
were noted. These changes were then compared to dental
overjet changes for all of the 18 control subjects in order
to find the one change with the most direct relation to
dental overjet change. The pre- and post-test differences
between the following planes were computed:
1. Point S to nasion (SN plane)
2. Point E to Point S
3. Point E to Point L
4. Point A to Point B (90° projection from SN plane)
Figure 4
A complete head film tracing illustrating
the angles measured
Age 11 yrs. 1 mo
B. J. Stansell
D» W. McCormack, Jr. Dental X-Ray Lab
/?-3 /S.s"n}/r;
7 ~ —J_ 'f
Co!S « " " y
i
!
m,
x*/>?/*&- 97.^'
- >5'
1 9 9 .
5. Midpoint of the mandibular incisal profile to Point
A (90° projection from SN plane)
6. Midpoint of maxillary incisal profile to Point A
(90° projection from SN plane)
7. Occlusal
8. Mandibular
9. Point S to midpoint of mandibular incisal profile
(90° projection from SN plane)
10. Point S to midpoint of maxillary incisal profile
(90° projection from SN plane)
11. SN plane to Point A (90° projection)
12. SN plane to Point B (90° projection)
The differences between the following angles were
computed:
1. Point S to nasion to Point A
2. Point S to nasion to Point B
3. Point A to nasion to Point B
4. Point B to Point S to nasion
5. Point A to Point S to nasion
6. Point B to Point S to Point A
7. Mandibular
8. Occlusal
9. FMIA (Frankfort mandibular incisal)
10. IMPA (incisal mandibular)
11. FMA (Frankfort mandibular)
Each plane difference and each angle difference was
plotted on a separate scattergram with the overjet differ
ence in order to determine which plane or angle difference
I
most nearly paralleled the overjet difference. Separate
scattergrams (Figure 5) to depict the overjet difference
with the three differences which showed the least scatter
were then plotted for all 18 of the control subjects. Be
cause the changes in the distance from the midpoint of the
mandibular incisors to Point A showed the most direct rela
tion to the changes in the dental overjets and because there
was no difference in the inclination of the mandibular inci
sors due to training (See Appendix H), adjustment of the
post-test overjet was made on this basis. If this distance
decreased, the amount of the decrease was added to the
actual overjet distance. If this distance increased, the
amount of the increase was subtracted from the actual over
jet measurement. Figure 6 shows the variation of the over
jets of the control subjects after adjustment for changes
assumed to result from growth. Figure 7 shows that the dis
tance from Point A to the midpoint of the maxillary incisors
(labial deflection) parallels the overjet change not assumed
to be due to growth. Figure 7 demonstrates further substan
tiation for the accuracy of the method for these particular
subjects. For illustration, compare Figures 1 and 8. The
pre-test overjet was 6 millimeters, and the distance from
the midpoint of the mandibular incisors to Point A was 3.5
millimeters. The post-test overjet was only 5.5 milli-
-x
-y
•X
x=Difference in overjet
y=Difference in ANB Angle
B
69
-y
x=Difference in overjet
y=Difference Points A to B
-x .X
2
-y
x=Difference in overjet
y=Difference in distance from midpoint of
mandibular incisal profile to Point A
Fig. 5.— Pre- and post-test differences
of the 18 control subjects
70
+3mm
3mm
Fig. 6.— Increase and decrease differences between
pre- and adjusted post-test dental overjets of the 18
control subjects.
71
-x -X
-y
x=Differences between pre- and adjusted post-test
dental overjet
y=Differences in pre- and post-test distance from
Point A to midpoint of maxillary incisal profile
Fig. 7.— Relation of differences between pre- and
adjusted post-test dental overjet to differences between
pre- and post-test distance from Point A to midpoint of
maxillary incisal profile of the 18 control subjects.
Female control subject ' i ~>
,Age 11 yrs. 10 mos.
Date 5/29/68
y
Fig. 8.— Tracing of the final x-ray of the same
control subject shown in Figure 1.
meters, but the change in mandibular-maxillary relationship
had placed the midpoint of the mandibular incisors .5
millimeters closer to Point A. The distance from Point A to;
[the midpoint of the maxillary incisors remained the same (2
millimeters); therefore, the assumption was made that growth
was responsible for the decrease in the overjet, and the
difference between the initial and the adjusted overjet was
zero. However, not all control subjects showed a zero
change. Six subjects did show this one-to-one relationship,
7 subjects varied ± .5 millimeter, and 5 subjects varied 1
or more millimeters. It is emphasized that the adjustment
procedure applies only to subjects in the present study. It
is possible that a longer waiting period would indicate
changes in the mandibular incisors that were the result of
training.
Methods Employed to Assure Accuracy
in Tracing the X-Rays
All arbitrary points were consistently maintained
for each subject by superimposing one acetate tracing over
the preceding one. The most anterior and the most inferior
outlines of the maxillary profile were traced without the
use of a template which was later used to complete the con
tour of the teeth. The most anterior and the most superior
outlines of the mandibular teeth were traced before the use
of the template. The same millimeter ruler was used for all
linear measurements.
......74
i
In order to obtain a check on the accuracy of the j
tracing and the accuracy of the measuring of the investi
gator, 18 x-rays were traced and measured by a professional
roentgenologist. (This number consisted of the pre- and
post-test x-rays of the subjects randomly selected.) The
two crucial measurements of each tracing (overjet and dis
tance from the lower incisors to Point A) were compared with
those previously completed by the investigator. Pearson's
coefficient of correlation was 0.977.
Each of the 116 overjets and all other distances
necessary for adjustment were measured by three individuals
working independently, the investigator and two disinter
ested persons. Thus, each initial and each adjusted overjet
measurement is a mean of three measurements.
Utilization of Data Other Than
Pre- and Post-Test X-Rays
Dental impressions were employed to corroborate the
orthodontists' observation of Angle's classification, to
check the accuracy of the occlusal films, and to aid in
tracing the dentition shown on the x-rays.
Interim x-rays were traced to check the progress of
the subjects and to aid in the tracings of the pre- and
post-test x-rays, but their measurements were not a part of
the dependent variable. Pre-test tape recordings were
evaluated to determine whether or not sigmatism was present
in all subjects. Interim tape recordings were evaluated to
; •......... 75
determine whether or not the experimental speech subjects j
had reached the criterion level of correction of sigmatism. |
Post-test tape recordings were evaluated to determine
whether or not speech correction was maintained by the expe
rimental speech subjects.
An interim check was made on the experimental deglu
tition subjects by counting the number of consecutive/
error-free training sessions noted in individual logs in the
kit notebooks. The check was made for the purpose of deter
mining when criterion level of correction of deglutition was
attained. A post-test count of the number of error-free
sessions between interim and post-test procedures indicated
whether or not deglutition correction was maintained.
Evaluation of the Data
The differences between the pre-test and the post
test dental overjets of all subjects were computed and
tabulated. One-tail t tests were utilized for the within-
group comparisons of the experimental speech group and the
experimental deglutition group. In order to compare the.
three matched groups, a repeated measurements analysis of
variance was performed. The Hartley test was utilized to
test the assumption that the treatment groups were drawn
from populations with equal variances. The Scheff^ test of
post hpc comparisons was employed for specific comparisons
among the three groups. The 0.05 level of significance was
accepted.
CHAPTER IV
RESULTS AND DISCUSSION
Each dental overjet recorded was the mean of the
measurements made by 3 individuals working independently,
the investigator and 2 disinterested persons. All actual
and adjusted overjet measurements were recorded to the near
est half-millimeter. Any millimeter measurement shown with
a fraction other than .5 is the result of statistical compu
tation. It should also be noted that there is a generally
accepted orthodontic opinion that any linear measurement of
an x-ray tracing may be in error by as much as .5 milli
meters .
Experimental Speech Group
The first hypothesis, that the particular technique
used in correction of sigmatism would decrease dental over
jet, was supported. The mean overjet measurement before
sigmatism training was 5.39 millimeters, and at the termina
tion of the study it was 4.94 millimeters, a mean decrease
of .45 millimeters. A one-tail test of the difference
between pre- and post-test means yielded a t ratio of -2.435
that with 15 degrees of freedom, was significant at less
76
! 77i
I i
than the .05 level. (See Table 8, Appendix L.) Not all of j
; j
the 16 experimental speech subjects improved, but the 10 j
jsubjects who did improve showed a mean decrease of one ;
millimeter. Two subjects showed no measurable difference,
and 4 subjects showed a mean increase of .5 millimeters.
Experimental Deglutition Group
The second hypothesis, that correction of degluti
tion would decrease dental overjet, was not supported. The
mean overjet measurement before deglutition training was
7.07 millimeters, and after training it was 6.91 milli
meters. The one-tail test of the overjet reduction yielded
a t value of -1.287 that with 17 degrees of freedom, was not
significant (p>.10), although the difference was in the pre
dicted direction. (See Table 9, Appendix M.) Eight of the
18 subjects did improve with a mean overjet decrease of .67
millimeters. Five subjects showed no measurable difference,
and 5 subjects showed a mean increase of .47 millimeters.
Comparison of Sigmatism Training,
Deglutition Training, and No
Training on Dental Overjet
The third hypothesis, that deglutition training
would be more effective than sigmatism training, was not
supported. To compare the differences in gain scores among
the 3 treatment groups, a repeated measurements analysis of
variance was performed because the 16 subjects in each group
were individually matched. A negative gain score was a
reduction in overjet; a positive gain score was an increase
in overjet. A summary of the anova is shown in Table 2.
The obtained F ratio of 8.742, with 2 and 30 degrees of
freedom, indicated that the differences among treatments
were significant at less than the .01 level of confidence.
The Hartley F max test, as suggested by Winer (1962), was
utilized to test the assumption that the variance due to
experimental error within each of the treatment populations
was homogeneous. The Hartley test of homogeneity with 3
variances, each with 15 degrees of freedom, yielded an F
max value of 1.986 that was not significant. Therefore, the
assumption of homogeneity was not violated.
Because the analysis of variance, as an overall
test, indicated significant differences among the 3 treat
ment groups, it was permissible to use an additional test to
compare the differences. The Scheffd method of post hoc
comparisons of group means was employed, as suggested by
Hays (1963). A summary of the Scheffe test is shown in
Table 3. Comparison of the experimental deglutition group
with the control group yielded a difference of .59 that was
significant at less than the .05 level of confidence and
indicated that deglutition training had more effect than no
training in reducing dental overjet. The Scheffe test of
the comparison between the experimental speech group and the
control group yielded a difference of .79 that was signifi
cant at less than the .01 level of confidence and indicated
TABLE 2
Summary of the Analysis of Variance of the
Difference Scores of the Three Matched Groups
Source ss df ms F
Between Subjects 11.05 15 8.742*
Between Treatments 5.42 2 2.71
Residual 9.30 30 0.31
*p<.01 df=2,30
TABLE 3
Summary of
of the
the Scheff^ Test of
Differences between
Post Hoc Comparisons
the Group Means
Treatment
Group
Mean Change
in
Dental Overjet
Comparison of the
Differences in Mean
Change of the
Dental Overjet
Deglutition Speech
Control + .34 .59* .79**
Deglutition -.25 - .20
Speech -.45
-
*p<.05. A difference of .51 between the means of
any two groups is necessary for significance at the .05
level.
**p<.01. A difference of .65 between the means of
any two groups is necessary for significance at the .01
level.
that sigmatism training was more effective than no training I
i ;
in reducing dental overjet. However, the obtained differ
ence of .20 between sigmatism training and deglutition
training was not significant. Sigmatism training, not !
deglutition training, was the more effective in reducing
dental overjet; but sigmatism training was not significantly;
more effective than deglutition training.
One of the obvious discrepancies between the t tests
and the Scheffe test was the result of discarding 4 sub
jects, 2 in Experimental Group D and 2 in Control Group C.
The most important difference between the 2 tests was that'
the Scheffe test compared each of the 2 experimental groups
with the control group that showed a mean overjet increase.
However, use of the Scheffe test to support Hypothesis 2
would have possibly been a type I error.
The Unmatched Subjects
The small mean overjet difference and the small num
ber of subjects in Experimental Group LM make unnecessary
any subjection to statistical computation. Three subjects
showed an overjet increase after performing lip exercises
and wearing the mouthpiece. Two subjects showed no measur
able difference, and one subject showed an overjet decrease.
The mean overjet change for the group was +.19 millimeters.
(See Table 12, Appendix P for pre- and post-test dental
overjet measurements for the individual unmatched subjects.)
| Discussion
| i
; Since the experimental speech subjects were given no;
instructions concerning tongue placement in swallowing, it
is assumed that the dental overjet decrease of the group was
the result of cessation of lingual pressure on the incisors
during the production of the /s/ and /z/ phonemes and the
result of application of labial pressure on the incisors.
This assumption would support the opinion of Schurter (1962)
that some corrective techniques would cause a labial deflec
tion of the incisors if careful attention were not given to
tongue placement during speech production. Jann, Ward, and
Jann (1964) observed that many of the children in their
investigation produced the /s/ by placing the tongue tip
lightly against the incisors but emitted the air stream
centrally so that an acoustically acceptable /s/ was pro
duced. It appears that sigmatism can be acoustically cor
rected without removing lingual pressure from the incisors.
The particular speech technique used with the subjects in
the present study both corrected sigmatism and decreased
dental overjet.
It is assumed that lingual pressure on the incisors
during swallowing and at rest was not as great as lingual
pressure during the /s/ and /z/ production of the experimen
tal deglutition subjects. It is emphasized that both the
experimental speech and the experimental deglutition groups
were given the same training to employ the muscles of facial
jexpression to produce a labial pressure on the incisors. Itj
should also be emphasized that the experimental deglutition |
subjects were overtrained. Three consecutive error-free j
training sessions were required for an experimental degluti-;
tion subject to meet his criterion level of correction, but
the mean number was 10 such sessions at the time of interim ;
measurements and evaluations. (See Table 7, Appendix K.)
The six unmatched subjects performed lip exercises
and wore the mouthpiece in the same manner as did the sub
jects in Groups D and S, and this training to employ the
muscles of facial expression to exert a labial pressure on
the incisors was initiated at the same time for all sub
jects, Experimental Groups S, G, and LM. Because only one
of the six unmatched subjects showed a decrease in dental
overjet, it is assumed that use of labial pressure on the
incisors in the absence of any training to remove lingual
pressure on the incisors is not indicated.
CHAPTER V
.SUMMARY, CONCLUSIONS, AND IMPLICATIONS
The Problem
This study was designed to investigate the effect of
deglutition training and the effect of speech training on
dental overjets of subjects who exhibited sigmatism, tongue-
thrust swallow, and dental overjet. Questions posed were:
(1) Will correction of sigmatism by the particular speech
technique employed in this study result in a decrease in
overjet? (2) Will correction of the pattern of deglutition
result in a decrease in overjet? (3) Will correction of
deglutition result in a greater decrease in dental overjet
than correction of the defective /s/ and /z/ in subjects who
exhibit tongue-thrust swallow, sigmatism, and dental over
jet? The principal hypotheses derived from the questions
were: (1) After correction of sigmatism by the technique
employed, the mean of the post-test dental overjet of the
speech group will be significantly less than the mean of the
pre-test overjet. (2) The mean post-test dental overjet of
the deglutition group will be significantly less than the
mean pre-test overjet. (3) The mean difference between pre-
and post-test dental overjet measurements of the experimen
84
tal deglutition group will be significantly less than the
mean difference between pre- and post-test overjet measure
ments of the experimental speech group.
The Method
All subjects exhibited tongue-thrust swallow, sigma
tism, and dental overjet. Three groups of 18 subjects each
were matched on the basis of sex, age, and, as many as pos
sible, on Angle's classification of dental occlusion. One
group received only deglutition training, one group received
only sigmatism training, and the remaining group received no
training and served as controls for both the experimental
deglutition group and the experimental speech group. Thus,
one subject served as a control for two experimental sub
jects, deglutition and speech. Two.experimental speech sub
jects did not finish training; and therefore, only 16 exper
imental speech subjects underwent post-test measurements.
Six subjects could not be matched on the basis of sex and
age, and they were given semi-training consisting of lip
exercises and a device designed to keep the mouth closed
during rest. The final sample consisted of 58 subjects.
Measurement and evaluation procedures consisted of (1) den
tal impressions, (2) lateral head x-rays with the teeth in
occlusion, and (3) high-fidelity tape recordings of a pas
sage consisting of 9 /s/ and 9 /z/ phonemes. Measurement
and evaluation procedures were conducted at 3 different
,times: (1) pre-test, before training; (2) interim, when an ;
experimental subject and his experimental match had both
reached the criterion level of correction; and (3) post
test, 3 months after each pair of matched experimental sub
jects had achieved correction. Only pre- and post-test den
tal overjet measurements comprised the dependent variable.
The other test proceedings were utilized for determination
of presence of sigmatism among groups, for determination of
achievement of criterion level of correction for experimen
tal subjects, and for assistance in the achievement of
accuracy of orthodontic opinions and of accuracy in tracing
the x-rays. A method was devised to distinguish the effect
of training and adverse muscular pressure from other forces,
involving growth, which affected dental overjet. The pre-
and post-test differences in dental overjet for all subjects
were computed; individual and group results were reported;
and the mean differences between pre- and adjusted post-test
dental overjet were compared within the 2 experimental
groups and among the 3 matched groups of 16 subjects each.
The statistical evaluations utilized were t tests, a
repeated measurements analysis of variance, and the Scheffe
test of post hoc comparisons. The 0.05 level of confidence
was accepted.
Results
The hypothesis that speech training would decrease
dental overjet was supported at less than the 0.05 level by
both of the statistical evaluations employed. The hypothe- ;
......... ' 87
; I
sis that deglutition training would decrease dental overjet *
was not supported by the t test, but it was supported by the
Scheffe test which compared the deglutition group and the
control group. The control group showed a mean increase in
dental overjet. In order to avoid a type I error, the null
hypothesis of no difference was accepted; and, thus, Hypoth
esis 2 was not supported. Obviously, Hypothesis 3, that
deglutition training would be more effective than speech
training in reducing dental overjet, was not supported.
Conclusions
The results of this study supported the following
conclusions;
1. The particular speech correction technique employed
in this study significantly decreases dental overjet
even though tongue-thrust swallow is present.
2. Deglutition training alone does not significantly
reduce dental overjet if the tongue-thrust swallow
is accompanied by sigmatism, but it does arrest an
increase in overjet.
3. Children aged 9 1/2 to 14 years, as a group, are
still subject to labial deflection of the incisors
when the children exhibit both tongue-thrust swallow
and sigmatism.
4. Methods used to exert outside lingual pressure on
the incisors, to prevent wedging, and to encourage
nose breathing have little or no effect on dental.
88
overjet in the absence of speech or deglutition
training.
5. Measurements of any type of training on the dental
overjet of a growing child should be based upon the
individual growth of the subject. This conclusion
was based upon the fact that pre- and post-test x-
rays revealed that variations in dental overjet
resulting from growth ranged from no change to an
increase of 1.6 millimeters and a decrease of 2
millimeters. Therefore, conclusions based upon the
comparison of pre- and post-test dental impressions
alone or based upon pre- and post-observations of a
particular growing child are unreliable.
Implications
The conclusions based upon the results of this
investigation were drawn within the limitations of the num
ber of subjects studied, the small differences between pre-
and post-test dental overjet measurements, the possibility
of error in tracing and measuring very small distances and
angles, the among-subject variables, the within-subject
variables, and the length of the interval between interim
tests and post-tests to allow time for the types of training
to affect the maxillary incisors and possibly the mandibular
incisors. With emphasis upon the limitations of the present
study, the following discussion and suggestions for further
investigation are proposed:
If the assumption can be made that the results of j
speech training and the results of deglutition
training are additive, a combination of both types
of training is indicated. It has been suggested
that the swallowing pattern be altered before speech
reeducation is initiated (Fletcher, Casteel, and
Bradley, 1961; Jann, Ward, and Jann, 1964). It is
suggested by the present investigator that a combi
nation of the two types of training employed in the
present study be investigated to determine if a
greater decrease (than the two separate decreases
noted in the present investigation) will result in
subjects who manifest tongue-thrust swallow, sigma-
tism, and overjet.
It is suggested that a study be conducted to inves
tigate changes in dental overjets of children who
receive no training but who manifest tongue-thrust
swallow, sigmatism, and dental overjet. The inves
tigation should cover a wide age span in order to
trace an increase to a point of stability or to a
decrease, if such a trend exists. Knowledge of the
presence or absence of a trend toward stability or
decrease in dental overjet would be of value to both
orthodontists and speech clinicians in determining a
time at which to initiate treatment or in determin
ing whether or not treatment is indicated.
GLOSSARY
90
GLOSSARY
Points
Point A:
Point B:
Point E:
Gn-Gnathion:
Go-Gonion:
Point L:
The deepest midline point on the premax
illae between the anterior nasal spine
and prosthion (after Baum, 1951). Pros-
thion: The point on the maxillary
alveolar process that projects farthest
in the midline in an anterior direction
(Stedman, 19 66).
The deepest midline point on the man
dible between the teeth and pogonion.
The point on the SN plane located
directly above the most posterior point
of the condyle (Steiner, 1959). Con
dyle: The rounded articular surface at
the extremity of the mandible.
The midpoint of the convex margin of the
symphysis of the mandible in the sagit
tal plane.
The midpoint of the convex margin of the
angle of the lower jaw.
The point on the SN plane formed by a
91
Point N-Nasion:
Point O-Orbitale:
Point P-Portion:
Point Po-Pogonion:
Point S:
Planes
Frankfort:
Mandibular:
Occlusal:
90° projection to pogonion (Steiner,
1959).
The junction of the frontal and nasal
bones.
The lowest point on the inferior bony
margin of the left orbit.
A machine registration of the superior
border of the external auditory meatus.
The most anterior point on the symphysis
of the mandible.
The center of the image of the bony
crypt (sella turcica) occupied by the
hypophysis cerebri.
The plane formed by connecting Point P
with Point 0.
The plane formed by connecting gonion
with gnathion. There are several me
thods of tracing the mandibular plane,
but the one used by Dougherty (1968) is
taken as the definition in this study.
However, another method (see Figure 4)
had to be utilized in order to measure
the angles originated by Tweed.
A line drawn between the average inter
section of the maxillary and mandibular
central incisors and the occlusion of
the molars (as used by Dougherty, 1968).
Angles
Mandibular:
Occlusal:
FMIA:
FMA:
IMPA:
Other Terms
1-1:
Mesial:
Distal:
The angle between sella-nasion and
gonion-gnathion. (Steiner, 1959.)
The angle between sella-nasion and the
occlusal plane. (Steiner, 1959.)
The angle between the Frankfort plane
and a line bisecting the mandibular
incisors. (Tweed, 1954.)
The Angle between the Frankfort plane
and the mandibular plane as interpreted
by Tweed (1954).
The angle formed by connecting the man
dibular plane and a line bisecting the
mandibular incisors. (Tweed, 1954.)
Used
The actual overjet difference; the dis
tance from the midpoint of the profile
of the cutting edge of the mandibular
incisors to the midpoint of the profile
of the cutting edge of the maxillary
incisors.
Toward the front of the mouth.
Toward the back of the mouth.
i...... “ ■ .......94
*
iBuccal: Toward the cheek.
Angle's Class I classification of occlusion: The mesiobuc-
cal cusp of the first permanent maxil
lary molar occludes in the buccal groove
of the first permanent mandibular molar.
This is normal molar relationship but
does not necessarily mean normal occlu
sion.
Angle's Class II classification of occlusion: The mesiobuc-
cal cusp of the first permanent maxil
lary molar is mesial to the buccal
groove of the first permanent mandibular
molar. Class II has two subdivisions:
Division 1, in which the maxillary
incisors are inclined labially and Divi
sion 2, in which the maxillary incisors
are inclined lingually.
APPENDIXES
[
95
i
APPENDIX A
ORTHODONTIC EXAMINATION FORM
96
ORTHODONTIC CHECK FORM DR.
NAME OF SUBJECT ______________________ BIRTHDATE ____________
1. AMOUNT OF OVERJET _______________________________________
2. ANGLE CLASSIFICATION ____________________________________
3. IS THERE PRESENCE OF TOOTH CROWDING WHICH WOULD LIMIT
DISTAL MOVEMENT OF THE INCISORS? _________________
4. IS A FRONTAL TONGUE THRUST. PRESENT? _______________ __
5. ARE TONSILS ENLARGED TO THE POINT THAT THE SUBJECT WOULD
BE A POOR RISK FOR TRAINING?
APPENDIX B
PARENT INFORMATION
991
PARENT INFORMATION
SUBJECT'S NAME: ____________________ BIRTHDATE:_______
i
PARENT AND/OR GUARDIAN: __________________________
ADDRESS: ____________________________ TELEPHONE:_______
MEDICAL HISTORY
Frequency of upper respiratory infections:
Operations:
T & A:
Other:
Allergies:
Asthma:
Mouth or nose breathing:
Illnesses:
Other medical information:
History of ear infections:
Other:
PERSONAL INFORMATION
Number of siblings:
History of thumb or finger sucking: Nail biting:
Infant feeding:
Previous speech or tongue training:
Orthodontic training contemplated:
Permanence in community:
Attitude toward research project:
Regularity of school attendance:
Other pertinent information:
APPENDIX C
JUDGES' CHECK LIST OF /s/ AND /z/
WORDS FROM PASSAGES I, II, AND III
i
(THIS
IS
SPECIAL
person
SAT
ZOO
lizards
SEE
resting
WIZARD
mouse
lizard
ZOO
REST
ZOO
WAS
NICE
PASSAGE I
/s/ and /z/ words
/s/3 _____
/z/3 _____
/s/1 _____
/s/2 _____
/s/1 _____
/z/1 _____
/Z/2 _____
/S/1 _____
/S/2 _____
/Z/2 _____
/S/3 _____
/Z/2 _____
/Z/1 _____
/S/2__________
/Z/1 _____
/Z/3 _____
/S/3 _____
/z/!
SUBJECT NUMBER
JUDGE NUMBER
RECORDING NUMBER
/s/ GOOD
/s/ DEFECTIVE
/z/ GOOD
/z/ DEFECTIVE
THIS
SPECIAL
PERSON
SUN
WAS
SAND
GLISTENED
ZIG-ZAGGED
CRABS
LOBSTER
EYES
LAZY
LIZARD
PEACE
ZEBRA
ZIPPED
ACROSS
PASSAGE II
/s/ and /z/ Words
/s/3_________
/s/1_________
/s/2_________
/s/1_________
/z/3_________
/S/1_________
/S/2 ___ -
/Z/1_________
/Z/3_________
/S/2 ____
/z/3_________
/z/2_________
/z/2_________
/S/3_________
/z/1_________
/z/1_________
/S/3_________
/Z/5
SUBJECT NUMBER
JUDGE NUMBER
RECORDING NUMBER
/s/ GOOD
/s/ DEFECTIVE
/z/ GOOD
/Z/ DEFECTIVE
IS
PERSON
ROSA
DANCED
WHISTLED
ZINNIA
SANG
Z.ING
ZIP
SOUND
LIZARD
HIS
NICE
PLA£E
AS
LIZARD
SCAMPERED
PLACE
PASSAGE III
/s/ and /z/ Words
/z/3_________
/s/2________ _
/z/2 ____
/ S /2 _______
/ S /2 _______
/ Z / 1 _______
/S/1 ____
/ Z / 1 _______
/z/1 ____
/s/1 ____
/z/2 ____
/z/3 ____
/s/3 ____
/s/3 ____
/z/3 ___
/z/2 ____
/s/1 ____
/s/3
SUBJECT NUMBER
JUDGE NUMBER
RECORDING NUMBER
/s/ GOOD
/s/ DEFECTIVE
/z/ GOOD
/z/ DEFECTIVE
APPENDIX D
SUMMARY OF THE ANALYSIS OF VARIANCE EMPLOYED
TO TEST DIFFICULTY DIFFERENCES AMONG
PASSAGES I, II, AND III
104
Summary of the Analysis of Variance
of the Difference Errors of
Passages I, II, and III
Source ss df Ms F
Between Passages 19 2 9.5 0.14*
Within Passages 3765 55 68.45
*Conclusion: Passages are of equal difficulty. The
Hartley test of homogeneity yielded an F max value of 1.228,
which, with 3 passages and 24 degrees of freedom, was not
significant.'
APPENDIX E
THE PLASTIC MOUTHPIECE
106
THE PLASTIC MOUTHPIECE
The concavity of the mouthpiece is cut to fit around
but not to touch the incisors. The subject holds the mouth
piece (approximately 1 mm in thickness) between the lips but
not touching the gingiva. A string or small chain attached
to the plastic allows the subject to wear the mouthpiece
around his neck during conversation or eating, but it serves
as a reminder for the periods when it can be worn.
APPENDIX F
LIP EXERCISE
108
109
LIP EXERCISE
The only lip exercise performed by the experimental i
speech, the experimental deglutition, and the 6 unmatched
subjects was as follows: The subject held his lower lip
down firmly with the forefinger but not touching either the
lower incisors or the gingiva. With teeth slightly parted,
he then depressed the upper lip as far as possible both
inferiorly and lingually against the upper incisors. The
subject maintained this position to a count of five in order
to achieve a score of one lip exercise.
APPENDIX G
INSTRUCTIONS TO THE JUDGES
: ".......................... Ill
: i
INSTRUCTIONS TO THE JUDGES
You will hear tape recordings of 58 children, each
may, or may not, be reading three different passages at
three different times. All subjects on one tape or another
had /s/ and /z/ defects. Some subjects will have had speech
training, but some will have not. There are only three
tapes, but they will be switched often. The number of pas
sages to be played on each tape has been determined by a
table of random numbers. The number of changes from one
tape to another has also been determined by a table of ran
dom numbers.
Before you hear each passage, you will be given a
check form listing in order the words upon which you are to
concentrate. The subject's code number and your identifica
tion symbol have already been noted on the sheet. The /s/
and /z/ sounds are underlined. The sound must be rated as
either good or defective. If you think that the sound is
not entirely good, make a check {y) on the line provided by
the phonetic symbol. The number above the symbol indicates
the position of the sound in the word (initial, medial, or
final). Signal if you wish to have a passage repeated. If
you recognize any voice, please disqualify yourself from
judging the speech of that individual. Ask as many ques
tions as you wish now, but do not converse after the begin
ning of the playing of the tapes.
APPENDIX H
INCLINATION OF MANDIBULAR INCISORS
112
TABLE 4
Pre- and Post-test Differences in the Distance
from Point B to Midpoint of the Mandibular
Incisors (Inclination of the Mandibular
Incisors) for the 3 Matched Groups
Control Group
Experimental
Speech Group
Experimental
Deglutition Group
1.
millimeters
- .50 + .50 .00
2. .00 .00 .00
3 - .50 .00 - .50
4. + .50 .00 .00
5. .00 + .50 + .50
6. .00 .00 .00
7. +1.00 - .50 - .50
8. .00 - .50 + .50
9. + .50 .00 + .50
10. .00 .00 .00
11. + .50 + .50 + .50
12. + .50 . +1.00 +1.00
13. .00 .00 .00
14. .00 .00 - .50
15.
--- --- ---
16. .00 .00 .00
17. -1.00 .00 - .50
18.
___
—
Total +1.00 +1.50 +1.00
Mean=l *5LPmm Mean=l; 5®.mm Mpansl•00mm
16 16 16 ■
Conclusion: No difference in inclination of man
dibular incisors among the 3 groups.
APPENDIX I
THE TOTAL NUMBER OF /s/ AND /z/ ERRORS OF THE THREE
MATCHED GROUPS BEFORE ANY TRAINING WAS INITIATED,
THE AVERAGES OF THE JUDGES' RATINGS, AND THE MEAN
NUMBER OF ERRORS FOR EACH GROUP
! 114 |
TABLE 5
The Total Number of /s/ and /z/ Errors of the Three Matched Groups before Any Training was Initiated,
the Averages of the Judges' Ratings, and the Mean Number of Errors for Each Group
Deglutition Speech Control
Subject Subject Subject
No. Judge B Judge C Judge E Average No. Judge B Judge C Judge E Average No. Judge B Judge C Judge E Average
No. of No. of No. of
s z s z s zs&z Errors s z s z s zs&z Errors s z s z s z s & z Errors
1 5 5 5 5 5 3 9.33
2 7 8 9 8 9 9 16.67
3 8 5 8 9 9 9 16.00
4 8 9 8 8 9 9 17.00
5 8 7 8 8 8 9 16.00
6 7 9 6 8 8 9 15.67
7 7 4 7 7 7 6 12.67
8 7 2 4 3 5 3 8.00
9 6 9 9 9 8 9 16.67
10 7 8 9 7 9 9 16.33
11 6 7 5 8 4 6 12.00
12 8 7 9 9 9 9 17.00
13 7 6 6 6 6 7 12.67
14 8 9 9 9 9 7 17.00
15 9 7 8 9 9 9 17.00
16 9 9 9 8 9 9 17.67
17 5 3 6 3 8 3 9.33
18 5 7 7 8 6 7 13.33
Total 260.34
Mean 14.46
1 7 9 8 8 9 9 16.66
2 7 8 7 8 5 9 14.66
3 8 8 8 6 9 6 15.00
4 6 9 6 8 6 9 14.66
5 6 5 5 4 7 4 10.33
6 7 8 9 9 9 9 17.00
7 7 7 8 7 7 6 14.00
8 9 ' 9 8 9 9 9 17.66
9 9 7 9 7 9 8 16.33
10 8 9 9 8 9 9 17.33
11 8 9 7 8 9 9 16.66
12 9 7 9 9 9 9 17.33
13 a 9 8 9 9 9 17.33
14
7 e
9 9 9 9 9 9 18.00
16 9 9 9 9 9
9
18.00
17 8 9 8 9 6 9 16.33
18
- - - - - - —
Total 257.28
Mean 16.08
1 7 9 6 3 8 9 15.66
2 3 9 3 8 5 8 12.00
3 7 8 6 7 7 7 14.00
4 9 7 9 8 9 9 17.00
5 9 6 9 7 6 5 14.00
6 5 3 6 6 6 4 10.00
7 4 6 4 5 5 8 10.66
8 8 9 8 9 9 8 17.00
9 7 6 8 8 7 5 13.66
10 9 8 9 8 8 8 16.66
11 8 5 7 5 7 4 12.00
12 7 7 9 8 8 8 15.66
13 8 8 8 9 9 9 17.00
14 8 7 9 8- 8 7 15.66
15 8 8 3 9 9 9 17.00
16 6 8 6 9 8 8 15.00
17 9 . 8 9 8 9 7 16.66
18 6 6 5 7 6 7 12.33
Total 261.95
Mean 14.55
115
APPENDIX J
THE TOTAL NUMBER OF /s/ AND /z/ ERRORS OF THE EXPERIMENTAL
SPEECH SUBJECTS ON THE SECOND AND THIRD RECORDINGS, THE
AVERAGES OF THE JUDGES' RATINGS, AND THE MEAN NUMBER OF
ERRORS ON BOTH RECORDINGS
116
TABLE 6
The Total Number of /s/ and /z/ Errors of the Experimental Speech Subjects
on the Second and Third Recordings, the Averages of the Judges* Ratings,
and the Mean Number of Errors on Both Recordings
Tape 2: Correction Tape 3: After Carry-Over Training
Judge B Judge C Judge E Average
No. of
Judge B Judge C Judge E Average
No. of
s z s z
s & z Errors
s z s z s z
s & z Errors
s z
1 0 2 1 0 1 1.66 0 1 0 0 0 1 .66
2 2 1 1 1 2 1 2.66 1 2 0 0 2 0 1.33
3 1 1 1 0 2 1 2.00 1 0 0 0 1 0 .66
4 1 2 1 1 2 1 2.66 0 2 0 0 0 0 .66
5 1 2 1 1 2 1 2.66 0 0 0 0 0 0 0.00
6 0 0 0 0 0 0 0.00 0 0 0 0 1 1 .66
7 1 1 0 1 1 1 1.66 0 1 0 1 0 0 .66
8 1 0 0 0 1 0 .66 0 1 0 1
★ *
1.00
9 0 0 0 0 0 0 0.00 0 0 0 0 0 0 0.00
10 0 0 1 0 0 0 .33 0 0 1 1 1 0 1.00
11 1 1 0 2 2 1 2.33 1 0 0 0 0 0 .33
12 0 1 0 1 0 1 1.00 0 0 1 0 0 0 .33
13 0 0 0 0 0 0 0.00 2 1 1 1 1 1 2.33
14
1 C
2 1 0 0 0 0 1.00 .1 1 0 0 0 0 .66
1j
16 1 0 1 0 1 0 1.00 0 0 0 0 1 0 .33
17 2 1 1 0 1 0 1.66 1 0 0 1 0 1 1.00
18
■ ~ ' “
Total 21.28 Total 11.61
Mean 1.33 Mean .73
*Judge Disqualified Self.
117
APPENDIX K
TOTAL NUMBER OF CONSECUTIVE ERROR-FREE SESSIONS
OF THE EXPERIMENTAL DEGLUTITION SUBJECTS BEFORE
THE SECOND X-RAY AND THE NUMBER OF ERROR-FREE
SESSIONS BETWEEN THE SECOND AND THIRD X-RAYS
118
TABLE 7
The Total Number of Consecutive Error-Free Sessions for the Experimental
Deglutition Subjects before the Second X-Ray and the Number of
Error-Free Sessions between the Second and Third X-Rays
Subject
No.
No. of Consecutive Error-Free
Sessions at Time of Second X-Ray
No. of Error-Free Sessions between
Second and Third X-Rays
1 5.00 9.00
2 13.00 4.00
3 3.00 4.00
4 11.00 10.00
5 20.00 10.00
6 13.00 10.00
* 7
/ 12.00 4.00
8 3.00 4.00
9 6.00 9.00
10 1 8.00 8.00
11 13.00 10.00
12 13.00 8.00
13 13.00 4.00
14 15.00 13.00
15 12.00 10.00
16 10.00 9.00
17 7.00 8.00
18 13.00 6.00
Total 190.00
Mean 10.56
Total 140.00
Mean 7.78
APPENDIX L
PRE- AND POST-TEST MEASUREMENTS OF THE DENTAL OVERJETS
OF SUBJECTS WHO RECEIVED ONLY SPEECH TRAINING, THE
DIFFERENCES BETWEEN THESE MEASUREMENTS, AND THE
MEAN AT EACH TIME OF MEASUREMENT
120
m i
TABLE 8
Pre- and Post-test Measurements of the Dental Overjets
of Subjects Who Received Only Speech Training, the
Differences between These Measurements, and the
Mean at Each Time of Measurement
Dental Overjet in Millimeters Difference
Subject between
No. Pre-test and
Pre-test Post-test Post-test
1 3.00 3.83 + .83
2 4.50 4.01 - .49
3 5.00 4.00 -1.00
4 3.17 3.17 0.00
5 5.50 5.34 - .16
6 5.00 3.50 -1.50
7 6.00 6.17 + .17
8 4.00 3.67 - .33
9 4.00 4.00 0.00
10 6.00 5.00 -1.00
11 6.00 6.50 + .50
12 5.00 4.00 -1.00
13 11.00 10.00 -1.00
14 7.00 7.50 + .50
16 6.00 4.50 -1.50
17 5.00 3.84 -1.16
18
___
Total 86.17 Total 79.03 Total -7.14
Mean 5.39 Mean 4.94 Mean - .45
SE diff. = .1848
one-tail t = -2.435*
15df
p=<.05
*t of -2.602 necessary for significance at the
.01 level.
APPENDIX M
PRE- AND POST-TEST MEASUREMENTS OF THE DENTAL OVERJETS
OF SUBJECTS WHO RECEIVED ONLY DEGLUTITION TRAINING,
THE DIFFERENCES BETWEEN THE MEASUREMENTS,
AND THE MEAN AT EACH TIME OF MEASUREMENT
122
123]
TABLE 9
Pre- and Post-test Measurements of the Dental Overjets
of Subjects Who Received Only Deglutition Training,
. the Differences between the Measurements,
and the Mean at Each Time of Measurement
Subject
No.
Dental Overjet
Pre-test
in Millimeters
Post-test
Difference
between
Pre- and
Post-test
1 10.50 10.50 0.00
2 7.17 7.17 0.00
3 9.00 9.00 0.00
4 5.50 5.00 - .50
5 8.00 6.50 -1.50
6 3.50 2.83 - .67
7 11.00 11.50 + . 50
8 4.00 4.00 0.00
9 5.17 5.50 + .33
10 4.00 3.17 - .83
11 3.83 3.83 0.00
12 13. 67 13.00 - .67
13 4.00 3.67 - .33
14 11.00 11.50 + .50
15 11.50 12.00 + .50
16 3.50 3.17 - .33
17 7.50 7.00 - .50
18 4.50 5.00 + .50
Total 127.34 Total 124.34 Total 3.00
Mean 7.07 Mean 6.94 Mean - .167
SE diff + .1298
one-tail t = -1.287
17df
p>.10
APPENDIX N
COMPARISON OF THE DIFFERENCES BETWEEN THE INITIAL AND THE
POST-TEST DENTAL OVERJET MEASUREMENTS OF SUBJECTS IN THE
THREE MATCHED GROUPS AND THE MEAN FOR EACH GROUP
124
TABLE 10
Comparison of the Differences between the Initial and the
Post-test Dental Overjet Measurements of Subjects in the
Three Matched Groups and the Mean for Each Group
Subject
No.
Pre- and Post-test Overjet
Differences in Millimeters
P
Speech Deglutition Control
1 +0.83 0.00 +0.17 +1.00
2 -0.49 0.00 +0.83 +0.34
3 -1.00 0.00 +0.50 -0.50
4 0.00 -0.50 +1.00 +0.50
5 -0.16 -1.50 -0.83 -2.49
6 -1.50 -0.67 -0.50 -2 .67
7 +0.17 +0.50 +1.34 +2.01
8 -0.33 0.00 -0.17 -0.50
9 0.00 +0.33 +1.00 +1.33
10 -1.00 -0.83 0.00 -1.83
11 +0.50 0.00 + .17 +0.67
12 -1.00 -0.67 +1.00 -0.67
13 -1.00 -0.33 +1.67 +0.34
14
1 R
+0.50 +0.50 0.00 +1.00
_LO
16 -1.50 -0.33 -0.50 -2.33
17 -1.16 -0.50 -0.17 -1.83
18
___ ___
Total -7.14 Total -4.00 Total 5.51
Mean - .45 Mean -0.25 Mean 0.34
APPENDIX 0
NUMBER OF /s/ AND /z/ ERRORS MADE BY THE UNMATCHED SUBJECTS
BEFORE ANY TRAINING WAS INITIATED, THE AVERAGES OF THE
JUDGES' RATINGS, AND THE MEAN FOR THE GROUP
126
TABLE 11
Number of /s/ and /z/ Errors Made by the Unmatched Subjects
before Any Training Was Initiated, the Averages of the
Judges' Ratings, and the Mean for the Group
Subject
No. Judge B Judge C Judge E
Average
Number
of
s & z Errors
s z s z s z
1 5 5 5 3 4 4 8.66
2 4 4 4 3 6 9 10.00
3 5 8 4 7 4 9 12.33
4 8 8 9 9 9 8 17.00
5 6 6 6 9 6 7 13.33
6 7 5 7 6 6 8 13.00
Total 74.32
Mean 12.39
APPENDIX P
COMPARISON OP THE DIFFERENCES BETWEEN PRE- AND POST-TEST
DENTAL OVERJETS OF THE UNMATCHED GROUP AND THE
MEANS FOR PRE- AND POST-TEST MEASUREMENTS
128
TABLE 12
Comparison of the Differences between Pre- and Post-Test
Dental Overjets of the Unmatched Group and the
Means for Pre- and Post-Test Measurements
Subject
No.
Dental Overjet
Pre-test
in Millimeters
Post-test
Difference
between
Pre- and Post-Test
1 M 7.67 8.33 +0.66
2 M 7.00 7.99 + 0.99
3 F 4.67 4.67 0.00
4 F 11. 00 11.00 0.00
5 M 4.00 3.17 -0.83
6 M 2.67 3.00 +0.33
Total 37.01
Mean 6.17
Total 38.16
Mean 6.36
Total +1.15
Mean +0.19
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Asset Metadata

Creator Stansell, Barbara Jones (author)

Core Title Effects Of Deglutition And Speech Training On Dental Overjet

Contributor Digitized by ProQuest (provenance)

Degree Doctor of Philosophy

Degree Program Communicative Disorders

Publisher University of Southern California (original), University of Southern California. Libraries (digital)

Tag health sciences, speech pathology,OAI-PMH Harvest

Language English

Advisor Perkins, William H. (committee chair), Dougherty, Harry L. (committee member), Garwood, Victor P. (committee member)

Permanent Link (DOI) https://doi.org/10.25549/usctheses-c18-388837

Unique identifier UC11361068

Identifier 7008544.pdf (filename),usctheses-c18-388837 (legacy record id)

Legacy Identifier 7008544.pdf

Dmrecord 388837

Document Type Dissertation

Rights Stansell, Barbara Jones

Type texts

Source University of Southern California (contributing entity), University of Southern California Dissertations and Theses (collection)

Access Conditions The author retains rights to his/her dissertation, thesis or other graduate work according to U.S. copyright law. Electronic access is being provided by the USC Libraries in agreement with the au...

Repository Name University of Southern California Digital Library

Repository Location USC Digital Library, University of Southern California, University Park Campus, Los Angeles, California 90089, USA