Close
About
FAQ
Home
Collections
Login
USC Login
Register
0
Selected
Invert selection
Deselect all
Deselect all
Click here to refresh results
Click here to refresh results
USC
/
Digital Library
/
University of Southern California Dissertations and Theses
/
Orthodontic confidence of senior dental students: a study of 2 US dental schools
(USC Thesis Other)
Orthodontic confidence of senior dental students: a study of 2 US dental schools
PDF
Download
Share
Open document
Flip pages
Contact Us
Contact Us
Copy asset link
Request this asset
Transcript (if available)
Content
ORTHODONTIC CONFIDENCE OF SENIOR DENTAL STUDENTS:
A STUDY OF 2 US DENTAL SCHOOLS
by
Chad Foster
_______________________________________________________________________
A Thesis Presented to the
FACULTY OF THE USC GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
MASTER OF SCIENCE
(CRANIOFACIAL BIOLOGY)
May 2010
Copyright 2010 Chad Foster
ii
Dedication
This thesis is dedicated to my family, Dave, Pat, Justin, and Megan. They have always
been with me on this long road and I owe all of my success and accomplishments to their
unconditional love and support.
iii
Acknowledgements
Dr. Glenn Sameshima: To my research advisor and chair of my research committee.
Thank you for the help and advice that you provided me on this project.
Dr. Robert Keim: Thank you for your willingness to lend advice whenever I needed to
pop into your office.
Dr. Alyssa Levin: Thank you for going above and beyond in your support of this project.
I cannot overstate how much I appreciate your help.
Dr. Reyes Enciso: Thank you for lending to this project your talents in data interpretation
and statistical analysis.
Figure 1: provided by the University of Queensland Australia,
www.uq.edu.au/.../selfDirect/selfDirect09.html
Figure 2: provided by www.thinkalytics.com
iv
Table of Contents
Dedication ii
Acknowledgements iii
List of Tables v
List of Figures vi
Abstract vii
Introduction 1
Literature Review 3
I. The Beginnings of Orthodontic Education 3
II. Undergraduate Orthodontic Education 4
III. Survey Research in Education 7
IV. Problem Based Learning 15
Hypothesis 23
Materials and Methods 24
Results 29
Discussion 46
Conclusion 50
References 52
v
List of Tables
Table 1: USC Survey statements 1-7 31
Table 2: USC Survey Statements 8-15 31
Table 3: USC Statement Groupings 32
Table 4: USC Clinical specialty rankings 33
Table 5: XYZ Survey Statements 1-7 39
Table 6: XYZ Survey Statements 8-15 39
Table 7: XYZ Statement Groupings 40
Table 8: XYZ Clinical Specialty Rankings 41
vi
List of Figures
Figure 1: Stages of Survey Research 9
Figure 2: The PBL Process 17
Figure 3: Survey on concepts of occlusion and malocclusion intervention 28
Figure 4: USC School of Dentistry Undergraduate Orthodontics Syllabus 29
Figure 5: USC respondents versus ranking of confidence in Enodontics 34
Figure 6: USC respondents versus ranking of confidence in Oral Surgery 35
Figure 7: USC respondents versus ranking of confidence in Orthodontics 35
Figure 8: USC respondents versus ranking of confidence in Pedodontics 36
Figure 9: USC respondents versus ranking of confidence in Periodontics 36
Figure 10: USC respondents versus ranking of confidence in Prosthodontics 37
Figure 11: XYZ School of Dentistry Undergraduate Orthodontics Syllabus 38
Figure 12: XYZ respondents versus ranking of confidence in Enodontics 43
Figure 13: XYZ respondents versus ranking of confidence in Oral Surgery 43
Figure 14: XYZ respondents versus ranking of confidence in Orthodontics 44
Figure 15: XYZ respondents versus ranking of confidence in Pedodontics 44
Figure 16: XYZ respondents versus ranking of confidence in Periodontics 45
Figure 17: XYZ respondents versus ranking of confidence in Prosthodontics 45
vii
Abstract
The purpose of the study was to gauge the orthodontic confidence levels of senior
dental students from the University of Southern California (USC) School of Dentistry and
one other US dental school (which will be referred to as XYZ Dental School) whom have
completed the necessary courses that their respective schools require them to pass in
order to be eligible recipients of the D.D.S. degree. This study examines teaching
contents and time
allocation within the undergraduate orthodontic curriculum at both
schools, as well as a survey, filled out by their senior dental students whom have
successfully completed such courses, concerning their confidence in a variety of
orthodontic concepts and treatment. The course directors at each school were contacted
and interviewed in detail about the nature of the course. A paper survey questionnaire
was distributed to each of the 144 members of the USC D.D.S. Class of 2010. Senior
dental students at XYZ Dental School were contacted through email and asked to fill out
an electronic copy of the survey posted on the website “Survey Monkey”
(surveymonkey.com). Results indicated that the 4
th
year dental students surveyed
assessed themselves as having a “moderate confidence” level in the majority of survey
statements. The students felt the strongest level of confidence in statements addressing
“occlusion” and the lowest levels in those statements addressing “orthodontic diagnosis”.
In regards to ranking the clinical specialties according to confidence, both groups of
students gave orthodontics the lowest markings
1
Introduction
The educators charged with the task of providing undergraduate dental students
with the orthodontic knowledge that their institutions require face a tough challenge.
Training which is lacking in theoretic basis and clinical experience is being presented to
future general practitioners who currently make up a large and growing percentage of the
total orthodontic providers in the real world. The course hours allotted to undergraduate
orthodontics are scarce, the faculty members needed to teach these courses are difficult to
recruit, and budget squeezes often complicate things further. One side might argue that
orthodontics should be left completely to specialists who have the proper education and
training in the field to provide the best treatment. Another might put forth the argument
that efforts to improve undergraduate orthodontic education would create overall more
knowledgeable general practitioners which would in turn lead to better case selection on
their part and improved treatment for both patients that they choose to accept or refer out.
The necessity of an effective undergraduate orthodontic experience can be judged
by considering how it clearly would benefit both orthodontists and general practitioners.
General practitioners need to know why and when to refer patients properly. They
should be made aware of the level of sophistication and complexity that goes into
orthodontic skills and treatment planning. They need to be taught what orthodontics can
accomplish in occlusion, in function, with profiles, for adults, with growth, with
orthognathic surgery, with early mixed-dentition treatment, and how to present these
benefits to their patients.
2
It is easy to understand how orthodontic treatment done poorly by individuals
with inadequate training would be alarming to orthodontic educators. Has the response,
by design or omission, been to protect orthodontic specialists by limiting the training
offered to dental students? Some evidence indicates that this attitude is
counterproductive. A 1974 dissertation by R. M. Little at the University of Washington
compared graduates from two dental schools in the same area. One school, with a strong
post-doc program, provided minimal exposure to the undergraduate students. The other
school offered 2 years of clinical experience and thorough grounding in theory to the
undergraduates. Graduates from the school which gave the most instruction referred more
cases to orthodontists, and a larger number expressed interest in orthodontic training.
(Dugoni, 1981).
Studies on the topic of undergraduate orthodontic education are not new to
literature. Researchers have looked at similarities between such courses at different
institutions, have tested implementing different forms of the curriculum, and have even
tested the undergraduate students for their knowledge on specific orthodontic principles.
It would stand to reason that actually knowing the relative confidence that these general
practitioners graduate with in orthodontic principles, diagnosis, and treatment could shed
light on a somewhat hot button issue in dentistry today.
3
Literature Review
I. The Beginnings of Orthodontic Education
In 1929, the first dental specialty board, the American Board of Orthodontics, was
born. Prior to 1930, a dentist had few options to further his learning in the field of
orthodontia. American colleges and universities had left orthodontic education to private
schools, and there were three of them that an applicant had to choose from. Two offered
eight week courses conducted at intervals throughout the year. The third school provided
a full calendar year of instruction. Entrance requirements to these schools were the
possession of the D.D.S. degree and a letter or recommendation on behalf of the
applicant.
These private courses were operated upon the belief that orthodontia was a part of
dentistry not unlike crown and bridge, or removable prosthetics and that a satisfactory
training in orthodontics could be acquired in a short rigorous course taken after dental
school. The average dentist that pursued such courses never questioned the type of
training he received. He accepted it because it was consistent with the ideas that his
dental school had imparted to him as an undergraduate, which held that his education for
the practice of orthodontics was complete except for any additional voluntary mechanical
training that he may wish to pursue.
The short courses offered by these three private schools supported these
viewpoints. Lectures consisted of elementary considerations of the denture, theories
regarding the process of tooth movement, and the perceived etiology of malocclusion. A
student’s time was divided between observing appliance manipulation and its results in
4
orthodontic clinic and the practice of mechanics of orthodontia at the laboratory bench.
Although these concentrated courses acquainted the student with the ramifications of the
science, it definitely placed the emphasis on mechanics and contributed to the over-
specializaiton of orthodontics along these lines. The result of this training was that
failures were attributed to improper appliance design and manipulation and most studies
in the field were directed toward their improvement.
The relative clinical success attained as a result of such training was sufficiently
satisfactory to stimulate complicated procedures and mechanical devices which
ultimately became limitations. With this beginning, it was only natural that orthodontia
should develop along mechanical lines, and as it did, the field further specialized and
separated itself from the rest of dentistry (Wright, 1947).
II. Undergraduate Orthodontic Education
A study was done by Adamadis based on a survey of teaching contents and time
allocation within the undergraduate orthodontic curriculum in 23 European countries in
1997, and on whether these countries created a formal undergraduate examination in
orthodontics. A questionnaire was mailed to faculty members (members of the Euro-
Qual Biomed II project). Completed questionnaires were returned by orthodontists from
23 countries. Orthodontics was taught in undergraduate curriculums of all countries
surveyed. The number of hours dedicated to orthodontics varied from 135 to 500 hours
with a mean of 245 hours. The time reported as allocated to theory, clinical practice,
laboratory work, diagnosis, and treatment planning varied greatly. In general, clinical
5
practice and theory were reported as being allocated most curriculum hours, while
diagnosis, lab work, and treatment planning received relatively less time. An
undergraduate examination in orthodontics was reported by 20 countries. It was
concluded that orthodontics makes up a small proportion of undergraduate dental
curriculum in most countries, and that the emphasis is on theory and clinical work
(Adamadis, 2000).
A study by Kindelan looked at whether or not changes to the undergraduate
course at Leeds Dental Institute resulted in increased student satisfaction. After 1993, the
school adopted a problem based learning variant for part of the course and started
emphasizing clinician led tutorials. The study was based on a questionnaire given to two
groups of 4
th
year students (one in 1993 and the other in 1995) comprising statements
related to the undergraduate course. The two groups of students were at the same stage
of their course on both occasions. Questions were in the form of 16 statements with
which students expressed a level of agreement, ranging from strongly agree to strongly
disagree. The numbers of responses at each level were compared between the groups. 8
of the 16 statements had more favorable responses in 1995 than in 1993, and no statement
received a less favorable response in 1995 than in 1993. It was concluded that changes to
the undergraduate course at Leeds Dental Institute aimed at increased problem-based
learning and clinician led tutorials resulted in improved student satisfaction (Kindelan,
1997).
A paper by Chadwick in the European Journal of Dental Education described how
an undergraduate orthodontic curriculum at the University of Manchester, which was
6
taught entirely in PBL format, was received by its students. Through surveying the
students it was found that the students liked the PBL format that the course was taught in,
but had concerns that they were uncertain as to what was expected of them in terms of
both breadth and depth of knowledge to be gained with PBL (Chadwick, 2002).
A study was done by Aly to develop and evaluate an interactive multimedia
courseware package in orthodontics and to provide dental undergraduate and
postgraduate students with an interactive means of self-study and self-assessment. The
majority of students in the study were very enthusiastic about this form of education
approach as they reported that it was helpful in understanding the orthodontic curriculum
more efficiently (Aly, 2003).
In 2002, Rock surveyed orthodontic teaching practices in the undergraduate
syllabi at British dental schools and tested the abilities of undergraduate students
according to the requirements of the GDC regulations. Information collected by means
of a questionnaire sent to each dental school in 1998 was compared with similar data
from 1994. Orthodontic knowledge and treatment planning ability of students was
assessed by a multiple choice exam completed by a random 10% student sample from
each school. In 1998, the average for the schools polled was that 195 curriculum hours
were dedicated to orthodontics and each student treated 5 patients. Fixed appliance
teaching had increased significantly between 1994 and 1998. As for the exam, students
scored well on questions that tested basic knowledge but much less well when asked to
apply that knowledge. Results supported the view that undergraduate orthodontic
7
training should concentrate on diagnosis and recognition of problems rather than on
providing limited exposure to treatment techniques (Rock, 2002).
Derringer in a 2005 study published in the British Dental Journal looked at the
current teaching of undergraduate orthodontics in UK dental schools and the changes that
these courses have undergone in the previous 3 years. Questionnaires were sent to
orthodontic course directors in each of the UK dental schools, and 12 dental schools
agreed to participate. The results showed that there was a wide variation in
undergraduate orthodontic course form and content in the 12 schools. The greatest
variation occurred in clinical teaching hours (50 to 126), the types of patient treatment
undertaken (removable only to full fixed), the laboratory teaching hours (0 to 60), the
content of the laboratory courses (removable appliances to fixed appliance typodonts),
and the course assessment. Quite a few schools reported reductions in their orthodontic
courses in academic, clinical and laboratory hours and content, and in the number of
teaching staff in the last 3 years (Derringer, 2005).
III. Survey Research in Education
Many educational research methods are descriptive, meaning they aim to describe
and interpret “what is.” “Such studies look at individuals, groups, institutions, methods
and materials in order to describe, compare, contrast, classify, analyze and interpret the
entities and the events that constitute their various fields of inquiry” (Cohen, 2007).
The typical goal of surveys is to collect data at a set point in time with the purpose
of describing the nature of existing conditions, identifying norms against which these
8
conditions can be compared, or defining the correlations that exist between specific
events. It is in this way that surveys can vary in regards to their level of depth from those
that offer basic frequency counts to those that describe relational analysis.
Surveys can further be divided relative to their scope. A survey typically has
several distinguishing characteristics and features that stand out. They can be used to
scan a broad field of issues, populations, institutions, etc, in order to quantify or describe
any generalized features.
Surveys are useful in research for a variety of reasons. First of all they gather
data on a one-shot basis and thus they are inexpensive and efficient in their purpose.
They can be used to represent a broad target population. It is for this reason that there is
a need for careful sampling. Surveys generate numerical data which aids in statistical
analysis. They are capable of providing descriptive, inferential and explanatory
information. Surveys manipulate specific factors and variables to derive frequencies (the
numbers registering a particular opinion or test score.) They gather standardized
information typically using the same instruments and questions for all of the study
participants which can be processed statistically. Surveys are able to capture data from
multiple choice, closed questions, test scores or observations schedules. They can
support or refute hypotheses about the target population, ascertain correlations, and
present material that is free of specific contextual factors. They are easily able to be
revised and can make generalizations about the goals that are being focused on. They do,
however, usually rely on large-scale data gathering from a wide population in order to
enable generalizations to be made about given factors or variables.
9
Surveys in education will often utilize test results, self-completion questionnaires,
and attitude or confidence scales. A researcher using this model usually will be seeking
to accrue large-scale data from as representative a sample population as possible in order
to state with a measure of statistical confidence that certain observed characteristics occur
with an amount of regularity, or that certain factors group together or that structured or
semi-structured interviews, self-completion or postal questionnaires, telephone
interviews, internet surveys, standardized tests of attainment or performance, and attitude
scales (Cohen, 2007). It is also typical for surveys to proceed through well defined stages
which are described in Figure 1
Figure 1: Stages of Survey Research
10
The process of formulating a survey proceeds from general to specific. A broad
research topic is sectioned into complementary subjects and questions, and for each
component, questions are made. It is critical that there be several items or questions for
each component issue; this ensures validity and reliability, and that the nature of the topic
is fully captured (Cohen, 2007).
Sapsford suggests that there are four main considerations in planning a survey.
The first deals with defining the problem that will be studied. The kinds and contents of
answers required must be decided upon, a hypothesis must be put forth for testing, and
the variables that are to be explored must be determined.
The second consideration is the sample selection. The target population of the
study must be identified. It is critically important to determine how access and
representativeness can be assured. Finally the study must consider if other samples will
need to be drawn for the purpose of comparison.
The third consideration is that of design of measurements. The study must outline
what will be measured, what variables will be required, and how reliability and validity
will be assured.
The fourth and final consideration is concern for the participants. It is the
responsibility of the study to protect confidentiality and anonymity, avoid pain to the
respondents, avoid hurting those who could be affected by the results, avoid overly
invasive questions, avoid participant coercion, and gather informed consent (Sapsford,
2006).
11
Rosier suggests that the planning of a survey will need to include clarification
certain parameters. The research questions to which answers need to be provided must
be clearly defined. The conceptual framework of the survey must be determined,
specifying in exact terms the concepts that will be used and explored. The instruments to
be used for data collection must be chosen. Sampling strategies and subgroups within the
sample are specified (unless the whole population is being surveyed, as in a census
return). Data collection practicalities and conduct in regards to permissions, funding,
ethical considerations, and response rates must be defined. Data preparation such as
coding, data entry for computer analysis, or checking and verification must be clarified
(Rosier, 1997).
It is important to pilot and pre-pilot a survey. There is a critical difference
between the pre-pilot and the pilot. The pre-pilot is typically a series of open-ended
questions that are used to generate categories for closed, typically multiple choice
questions. The pilot is used to test the actual survey instruments itself. Not all survey
studies choose to use a pre-pilot survey, but it is often helpful in creating the true pilot
survey that is representative of the research questions to be addressed.
A rigorous survey should be able to create clear, specific objectives and research
questions, guarantees that the instrumentation, sampling, and data types are correct to
yield answers to the research questions, ensures that as high a level of sophistication of
data analysis is undertaken as the data will sustain (Cohen, 2007).
Sampling is a key component of a survey study. Due to the fact that questions
about sampling arise directly from defining the population upon which the survey is to
12
focus, sampling decisions must be made early in the overall planning of a survey study.
Due to factors of expense, time, and accessibility, it is not always possible for researchers
to obtain measures from a population. Therefore, researchers seek to collect information
from a smaller subset of the population in such a way that the knowledge gained
theoretically represents the total population under study. In survey research, this smaller
group or subset is referred to as a sample. Those who are experienced in survey research
will start with the total population and work down to the sample. It is not as effective to
work from the bottom up, which would be determining the minimum number of
respondents needed to conduct a successful survey. Unless the total population is
identified in advance, it is nearly impossible to assess how representative the sample is
that they have drawn.
There are two methods of sampling. The first yields probability samples in which
the probability of selection of each respondent is known. These types of samples include
simple random samples, systematic samples, stratified samples, cluster samples, stage
samples, and multi-phase samples. Their advantage is the ability to generalize the data
that is gathered.
The second method of sampling is non-probability sampling. These samples
include convenience sampling, quota sampling, dimensional sampling, purposive
sampling, and snowball sampling. These kinds of samples do not generalize from the
data collected, each type of sample seeks only to represent itself. “The researcher will
need to decide the sampling strategy to be used on the basis of fitness for purpose, in
13
parallel with considerations of, for example, the representativeness of the sample, the
desire to generalize, the access to the sample, and the size of the sample” (Cohen, 2007).
Between 1993 and 1995 there were over 900 dissertations in educational
administration that employed some type of sample survey data (ProQuest File, 1995). As
one would expect, sample design is critical to the quality of the survey research (Babbie,
1990, Deming, 1960; Dillman, 1978, 1991; Jollifie, 1986; Kish, 1965, Pena &
Henderson, 1986; Yates, 1960). There are two components to sample design: the
selection technique and the estimation technique. Although there are many
considerations to take into account in sample design, the selection process is particularly
critical because this process is the foundation for the subsequent estimation process. If
there is not an accurate selection process, the estimation process is inherently subject to
difficulties (Wang, 1997).
In educational research, as in other fields, a project employing sample survey
method is not typically concerned with the sample statistics itself, but rather the focus is
most often in generalizing or estimating the sample statistics to the population. In order
to meet this requirement, it is important that a good sample is chosen and that a suitable
statistical analysis is conducted. The statistical theory for sampling from a finite
population highlights the importance of sample design, works towards a design that is
unbiased, and depends upon completely random selection to induce probabilities. This is
typical of most educational survey studies. Also, because each unit of the finite
population must be individually recognizable, it is critically important to clearly outline
the population that will be the focus of the study (Kish, 1965; Hedayat & Sinha 1991). In
14
regards to survey studies, a population means a target population. In the majority of
cases this is an ideal but practically inaccessible population. This is why a survey
population, otherwise known as an operational population, is sampled instead. After the
target population is determined, a survey population can be defined and a sampling frame
can be constructed. Different selection strategies will be chosen depending on the range
of the study. No matter which sampling strategy is employed, the goal is to collect a
sample that accurately represents the population on the variables of interest so that the
statistics of the sample can be generalized to the population as accurately as possible
(Wang, 1997).
The estimation of population dimensions from a single random sample which has
a high response rate does not cause a problem in data analysis. When a sample is
selected with a design that uses something other than simple random sampling (which is
called a complex sample), the estimation is often much more difficult and complex.
Usually survey sampling necessitates taking into account sampling design features in the
estimation process (Kish, 1965; Lee, Forthofer, & Lorimor, 1989; Scheaffer, Mendenhall,
& Ott, 1990). This is due to the fact that complex designs have different design
efficiencies compared to a simple random design. This design efficiency is termed
design effect, which is the ratio of a complex variance estimate to a simple variance
estimate (Kish, 1965). All else being equal, in terms of efficiency, a stratified design is
better than a simple random design, which is better than a cluster design (Wang, 1997).
Nonresponse problems call for special attention the selection and estimation
processes of the educational survey study. Survey nonresponse refers to the failure to
15
obtain measurements on sample units (de Leeuw, 1992). To simply put it, nonresponse
results in missing data. There have been previous studies that looked at nonreponse
problems as they relate to educational research ( Aiken, 1988; Johnson, 1992;
McNamara, 1994). When nonresponse occurs in research it often raises the question of
potential bias in the findings. The basis for the bias comes from the likelihood that
nonrespondents are different from respondents (Borg & Gall, 1996). It has been shown
that following-up and the use of incentives might improve response rates and curb the
effects of nonresponse (Armstrong, 1975; Babbie, 1986; Shultz & Luloff, 1990). Making
certain statistical adjustments such as weighting or post-stratification may also help to
compensate for nonresponse (Lin & Schaeffer, 1995; Zanutto, 1993). Of course, one
should always be careful when evaluating and generalizing any findings there is a low
response rate in the sample (Wang, 1997).
IV. Problem Based Learning
Problem Based Learning is an educational pedagogy that has the learners actively
engaged in problem solving situations that are authentic to the environment in which they
would be used. The emphasis of this model is that the students act as constructors of
their own learning in a context similar to that in which they would apply that knowledge.
The PBL learner is forced to think critically and creatively and to be responsible for their
own understanding.
Problem based learning differs significantly from other seemingly similar
problem or case based approaches. Traditional case based learning strategies use the
16
cases to test one’s understanding. The topic is first covered and then the case is presented
to help test the students’ understanding and re-affirm targeted topics of importance.
However, in Problem Based Learning, all of the learning is derived from exploration of
the problem. Learning is thus structured in the context of the problem.
Other case approaches simply use the case as an example to reinforce learning
rather than using it to develop the metacognitive skills associated with problem solving or
professional life. “The contrast is perhaps that the PBL approach is a cognitive
apprenticeship focusing on both the knowledge domain and the problem solving
associated with that knowledge domain or profession” (Wilson, 1996).
Problem Based Learning (PBL) was created in medical education in the 1960’s
and has since been adopted in over seventy medical schools. PBL is most commonly
used during the first two years of medical science curricula, where it is used in place of
traditional lectures on the basic sciences (anatomy, physiology, biochemistry.) This
pedagogy has also been embraced in another of other areas in education including
schools of law, education, business, dentistry, and many more.
Students themselves are separated into small groups, typically five to ten, with
each group being assigned a facilitator (who in a traditional model would be considered
the teacher or instructor). The students are then presented with a small passage or
narrative which describes a situation surrounding a central problem. The students are
unaware of what the problem will be ahead of time. Once they have read the passage
they begin by identifying relevant facts of importance in the case. Next the students
attempt to generate hypotheses or ideas on issues that are unclear to them within the
17
passage. Finally the students identify and list topics that will require further learning or
study in order to clarify certain aspects of the case relevant to the problems presented
within. It is in this way unique that Problem Based Learning does not specifically present
students with what they need to learn, rather, the students generate their own learning
needs based on their interpretation of the problem (See Figure 2)
Figure 2: The PBL Process
At the end of each group session, the students divide up the learning need topics
and engage in independent self-directed learning. Typically there is no set list of
textbooks that the students must be limited to. Information can be gathered from any
18
reputable source of academic literature or appropriate computer database. The students
compile the information relevant to their assigned topic into a document which will be
sent out to the other group members, who in turn will do the same. The students study
and review the prepared paper from each of the group mates and in so doing, come to a
better understanding of the learning need topics previously identified in the group
meeting.
Following this period of self-directed learning, the students once again meet as a
group. They give one another feedback as to what has been clarified since the last
session and what this new information means relative to the problems in the case. The
students are then presented with a second part of the original passage or narrative and the
group interaction and self-directed learning cycle continues. Typically there are multiple
parts or passages to each case, with each one leading the students to a deeper
understanding of the central problem or problems and also the collateral learning issues
surrounding it.
At the conclusion of the case the students engage in peer and self-evaluation.
Certain adaptations of Problem Based Learning have the students take a formal
assessment for grading purposes at the end of the case or a number of cases, while other
forms of PBL do not embrace this type of traditional assessment and grading (Wilson,
1996)
The role of “teacher” in a traditional model is replaced by the PBL “facilitator”
which is actually quite a bit different than the former. Unlike a traditional teacher, the
facilitator is not intended to be a primary source of information for the students. His or
19
her role is rather to indirectly guide the flow of thoughts and active learning that the
students are taking part in. A true PBL facilitator should only intervene in student
discussions if the active learning process begins to stagnate or if the students seem to be
getting too far off topic in their direction of focus. The ability of the tutor to use
facilitory teaching skills throughout the small group learning process is the biggest
determinant of the quality and the success of any educational method aimed at (1)
grooming students’ thinking or reasoning skills (problem solving, metacognition, critical
thinking) as they learn, and (2) helping them to become self-reliant, self-directed learners
(learning to learn, learning management). Tutoring is a teaching skill critical to problem-
based, self-directed learning (Wilson, 1996).
It is the role of the facilitator to ask questions that challenge the student’s
background knowledge on a subject. It is in this way that the facilitator can indirectly
step in and guide the students to certain objectives that they may have overlooked or
incorrectly held to be true. At the same time the facilitator must avoid using his or her
own understanding on the information to ask questions that will easily lead the students
to answers and inhibit the self-directed learning atmosphere of the group.
The learning environment that Problem Based Learning provides is meant to
simulate and actively immerse the student in problem solving behavior that a person in
the real field of study would be expected to be engaged in. There is no cookbook for
learning that the students can simply pace through step by step. To be successful,
students must adopt self-directed learning skills that they will most likely need in their
actual profession. Students also benefit from being conditioned on how to locate
20
pertinent information relative to their problem and also how to evaluate that information
in regards to its accuracy. “The entire problem solving process is designed to aid the
students in developing the hpothetico-deductive problem solving model which centers
around hypothesis generation and evaluation” (Wilson, 1996).
It is the task of those charged with designing the PBL cases to make sure that the
case problems direct the students towards concepts and principles that are targeted as
important for them to know. It is also important that the problems be relevant and real to
the students. For example, in medical and dental PBL curricula, students are often
introduced to a patient who is suffering from a certain condition and are asked to work
their way through the case to a proper diagnosis and treatment. This real life problem
serves to engage the students in the role of the health care provider and challenges them
to assume the responsibility that goes along with it. Making the problem real to the
student and encouraging them to take ownership of it fosters the environment of self-
directed learning which is so crucial to Problem Based Learning.
One problem that can arise when developing a PBL case is when the data
presented too easily and directly leads the students to the critical end-point learning
outcomes. The phrase “it’s not about the finish, it’s about the journey” aptly applies to
Problem Based Learning. Within certain parameters, students are expected to weave
their way through collateral case information and learning objectives on their path to the
central targeted learning outcomes.
Hmelo-Silver, Duncan, & Chinn reference multiple studies supporting the success
of the constructivist problem-based and inquiry educational methods. For example, they
21
describe a study called GenScope, an inquiry-based science software program. Students
utilizing the GenScope software displayed significant gains over the control groups, with
the biggest gains shown in students from basic courses (Hmelo-Silver, 2006).
Hmelo-Silver et al. also cite a study on the effectiveness of inquiry-based science
for middle school students, as demonstrated by their performance on standardized tests.
There was a 14% improvement for the first cohort of students and a 13% improvement
for the second cohort. This study additionally found that inquiry-based teaching methods
reduced the achievement gap for African-American students (Hmelo-Silver, 2006).
A review of the effects of problem-based learning on the perfomance of doctors in
medical school after graduation demonstrated positive effects on physician competence.
This effect was especially strong for social and cognitive competencies such as coping
with uncertainty and communication skills (Koh, 2008).
Sweller and others have published a number of studies over the past twenty years
that relate to problem-based learning but concerning cognitive load and what they call the
guidance-fading effect (Sweller, 2006). Sweller, et al. conducted multiple studies with
students studying algebra (Sweller, 1988). These studies have shown that active problem
solving in the beginning of the learning process, is not as effective instructional strategy
than studying worked examples. Certainly active problem solving is beneficial as
students become more competent, and able to deal with their working memory
limitations. However, learners may find it difficult to process a large amount of
information in a short amount of time early in the learning process. Thus the rigors of
22
active problem solving may prove difficult for novices. Once students gain experience
the scaffolding inherent in problem-based learning aids learners in avoiding these issues.
Sweller (1988) proposed cognitive load theory to describe how novices react to problem
solving in the early stages of learning. Sweller, et al. suggests a worked example in the
beginning, and then a tapered introduction of problems to be solved. They propose other
types of learning in the beginning of the learning process (worked example, goal free
problems, etc.); to later be replaced by completions problems, with the goal of solving
problems on their own (1998). This problem based learning becomes quite useful later in
the learning process.
Many forms of reinforcement have been worked into problem based learning to
reduce the cognitive load of learners. These are most useful to diminish guidance during
problem solving. As an example, consider the fading effect helps learners to gradually
move from studying examples to solving problems.
23
Hypothesis
I. Hypothesis, Ha:
Dental students graduate with a high level of confidence in concepts of orthodontic
principles, occlusion, diagnosis, and treatment planning, and feel high confidence in
clinical orthodontics as compared to the other clinical dental specialties.
II. Null Hypothesis, Ho:
Dental students graduate with a low level of confidence in concepts of orthodontic
principles, occlusion, diagnosis, and treatment planning, and feel low confidence in
clinical orthodontics as compared to the other clinical dental specialties.
24
Materials and Methods
This study was approved by the University of Southern California Health
Sciences Institutional Review Board (HSIRB). The IRB approval ID is HS-09-00611.
Undergraduate orthodontic course syllabi were obtained from the course directors
at both the University of Southern California School of Dentistry (Figure 4) and XYZ
Dental School (Figure 5).
The two samples selected were the University of Southern California School of
Dentistry D.D.S. Class of 2010 and XYZ Dental School D.D.S. Class of 2010. Both of
these groups of students had already completed their respective schools’ required
undergraduate orthodontic courses and had no further courses scheduled in this subject.
Inclusion Criteria:
The criteria for inclusion were the following:
1. Participant must be in his or her final (4
th
) year of study in the D.D.S.
program.
2. Participant must have passed or satisfactorily completed all of the dental
schools courses in undergraduate orthodontics and occlusion
Exclusion Criteria:
In addition, the criteria for exclusion from participation were the following:
1. 4
th
year D.D.S. students who had not started dental school at their present
institution (e.g. transfer students or 2-year international students) would not
be allowed to participate in the study.
25
Data Collection:
The survey titled “Survey on concepts of occlusion and malocclusion
intervention” (Figure 3) was made available to potential participants. Over the course of
2 weeks at USC, 136 out of 144 senior dental students were personally handed a paper
copy of the survey and asked to participate (There were 8 dental students that were
unable to be located). Students were informed that their participation would remain
anonymous and that participation would neither harm nor benefit them in any way. They
were additionally informed that the survey was part of a study by a post-doctoral dental
student as part of his master’s thesis. Upon being handed the survey by a 3
rd
party
independent of the study, the potential participant either filled the survey out on the spot
and gave it back to the 3
rd
party, or declined participation.
At XYZ, an email was sent out to the 55 senior dental students asking them to
participate in the study by going to the website “Survey Monkey”
(www.surveymonkey.com) to fill out an electronic copy of the survey posted on the
website. The website did not require the students to pay, register, sign-in, or otherwise
identify themselves. The email sent out informed the students that their participation
would remain anonymous and that participation would neither harm nor benefit them in
any way. They were additionally informed that the survey was part of a study by a post-
doctoral dental student as part of his master’s thesis.
26
Assumptions:
There are many factors that could contribute to a student’s confidence in the
orthodontic topics that were surveyed. Therefore, this study was based on the following
assumptions:
1. That all of the students derived their knowledge and understanding on the
orthodontic topics surveyed solely from their respective school’s
undergraduate orthodontic courses, and that no students had the benefit of
additional supplementary or advanced courses or learning experiences in this
field (in or out of their school).
2. That for the final question that asks the students to rank the specialties in order
of confidence, that they have also finished and successfully completed all of
the coursework that their school requires in these fields.
Method Error
The final question on the survey that asked the students to rank the specialties in
relation to their clinical confidence could have been stated more clearly to ensure that the
participants understood what the question was asking. The question should have specified
that “#1” meant the specialty in which they had the highest confidence and that “#6”
meant the specialty in which they had the lowest confidence. Also it should have been
specified that each number was to be used only once when ranking the specialties.
Statistical Analysis
For the first 15 confidence statements on the survey a 5-item Likert scale was
used to capture participant responses. A likert scale is a psychometric scale commonly
27
used in questionnaires, and is the most widely used scale in survey research. When
responding to a Likert questionnaire item, respondents specify their level of agreement to
a statement. Often five ordered response levels are used, although many
psychometricians advocate using seven or nine levels; one empirical study (Dawes, 2008)
found that a 5- or 7- point scale may produce slightly higher mean scores relative to the
highest possible attainable score, compared to those produced from a 10-point scale, and
this difference was statistically significant.
To test for differences in clinical confidence among DDS students between the six
specialties, the non-parametric Friedman’s test was used. To test for differences in
clinical confidence among DDS students between two specialties, the non-parametric
Wilcoxon Rank Sum test was used. To adjust for multiple testing we used the Bonferroni
correction with alpha=0.05/15=0.003, with 15 pairs of comparisons between level of
confidence in the different specialties.
To test for differences between categories of statements of a similar nature, we
organized the statements into four categories: statements 1-2 deal with occlusion; 3-7
deal with orthodontic diagnosis; 8-9 deal with basic orthodontic principles; and 10-15
deal with orthodontic treatment. The study compared the level of confidence among
DDS students between two categories of statements using the Wilcoxon Signed Ranks
test. To adjust for multiple testing we used the Bonferroni correction with
alpha=0.05/6=0.008, with 6 pairs of comparisons between the 4 groups of questions
(orthodontic treatment, orthodontic diagnosis, orthodontic principles and occlusion).
28
Figure 3: USC DDS Class of 2010
Survey on concepts of occlusion and malocclusion intervention
Please score each statement in regards your own level of confidence.
1- no confidence, 2- low confidence, 3- moderate confidence, 4- high confidence, 5- complete confidence
1. I understand the different aspects of ideal occlusion and occlusal function
1 2 3 4 5
2. I am able to diagnose different types of malocclusion and improper occlusal function
1 2 3 4 5
3. I am confident in my understanding of craniofacial growth and development
1 2 3 4 5
4. I am able to identify time points of adolescent maturity and understand their
importance in regards to dental treatment
1 2 3 4 5
5. I am able to evaluate orthodontic cases in regards to level of difficulty
1 2 3 4 5
6. I understand the steps in orthodontic diagnosis
1 2 3 4 5
7. I am able to trace a cephalometric film and use it for diagnostic purposes
1 2 3 4 5
8. I understand the biology/physiology of orthodontic tooth movement
1 2 3 4 5
9. I understand the basic bio-mechanic principles associated with standard orthodontic
treatment
1 2 3 4 5
10. I understand the goals of standard orthodontic treatment
1 2 3 4 5
11. I understand how to sequence orthodontic treatment in conjunction with other dental
treatments
1 2 3 4 5
12. I am confident in the application of limited orthodontic treatment (molar uprighting,
maxillary dental expansion, other limited movements)
1 2 3 4 5
13. I am confident in the techniques and timing of space maintenance in primary and
mixed dentition
1 2 3 4 5
14. I understand the strengths and limitations of different appliances (standard brackets,
invisalign, lingual braces, etc.)
1 2 3 4 5
15. I am able to evaluate and critique a finished orthodontic case
1 2 3 4 5
**Please rank (from #1 to #6) the different specialties in relation to your clinical confidence
endodontics oral surgery orthodontics pedodontics periodontics prosthodontics
____ ____ ____ ____ ____ ____
29
Results
Figure 4: USC School of Dentistry Undergraduate Orthodontics Syllabus
I. BASIC INFORMATION
• Course ID: --
• Course Title: Orthodontics
• Course Type: PBL/Lecture and Laboratory
• Program: DDS and ASPID
• Students: Class of 2010
• Semester and day/time: Fall 2008 and Spring 2009
o Wednesday: Sim Lab 10:00 AM to 12:00 PM
o Wednesday: PBL/Lecture 8:00 AM to 9:50 AM
• Units: --
• Name of Instructor(s): Dr. Ralph Allman
Dr. James Mah
o Office: DEN 312
o Office Hours: Tuesday 9am -12noon; Wednesday 9am-12noon
o Phone Number: Dr. Allman (213) 740-2686; Dr. Mah (213) 740-3762
• E-mail Address: jamesmah@usc.edu and allman@usc.edu
II. COURSE/UNIT DESCRIPTION
This preclinical PBL/lecture and laboratory course is an introduction for the general practitioner in the
evaluation, prevention, and treatment of dentofacial malformations. Fundamentals of dental development,
etiologies of malocclusion, somatic and craniofacial growth and development, biology of tooth movement,
osteology, and radiology are emphasized. Students are taught how to construct the basic appliances used to
treat orthodontic problems encountered in a general practice.
III. COURSE/UNIT OBJECTIVES
1. To learn and understand the fundamentals of dental development, etiologies of malocclusion, somatic
and craniofacial growth and development, biology of tooth movement, osteology, and imaging and
radiology pertinent to orthodontics
2. To understand concepts of interceptive and preventive orthodontic treatment.
3. To understand the production and utilization of orthodontic records (study casts, photographs, and
radiographic images) for diagnosis and treatment planning.
4. To learn how to take impressions, mix and pour plaster and trim orthodontic models.
5. To learn the basics of orthodontic appliance design and dental materials
6. To learn the usage and fabrication of a Palatal Expander appliance
7. To learn the usage and fabrication of a Maxillary Hawley appliance
8. To develop skills in fabrication of acrylic and wires for orthodontic appliances.
IV. COMPETENCY ALIGNMENT
1. Perform a comprehensive diagnostic evaluation based upon the application of scientific principles, and
current literature, with consultations as appropriate. (USCSD #8)
30
Figure 4 continued: USC School of Dentistry Undergraduate Orthodontics Syllabus
2. Recognize needs for orthodontic treatment, performing uncomplicated procedures and referring
complicated procedures. (USCSD #20)
3. Regularly assess one’s knowledge and skills, and seek additional information to correct deficiencies and
enhance performance. (USCSD #4)
V. LEARNING RESOURCES
1. Contemporary Orthodontics, 4
th
Edition by William Profitt
2. Orthodontics - Current Principles and Techniques, 4
th
Edition by Thomas M. Graber, Robert L.
Vanarsdall, Jr., and Katherine W. L. Vig
3. Laboratory Manual by Ralph Allman and James Mah
4. Cepalometrics Manual by Ralph Allman and James Mah
VI. SCHEDULE/COURSE CALENDAR
Didactic Lecture and Laboratory Schedule:
All PBL/lectures and labs will be given on Wednesday from 8:00 am to 9:50 am. PBL Cases will
be conducted in the Simulation Laboratory and selected rooms. Lectures will be held in the
Rutherford Lecture Hall. Laboratory sessions will be held in the third floor Simulation lab.
Attendance:
Attendance is mandatory for all lectures and lateness or absence will result in a lower grade in the
course. Students are accountable to the USCSD Attendance policy.
Schedules:
Please see the schedules for the PBL/Lecture and Laboratory Components for Fall 2009 and
Spring 2010 at the end of this document.
VII. COURSE/UNIT REQUIREMENTS AND GRADING/EVALUATION
Attendance is mandatory for all lectures and labs. Daily quizzes will be given promptly at 8:00 am.
Absences or lateness in either the PBL cases/lecture or lab will result in a lower course grade. Lack of
daily progress in the either the PBL sessions or laboratory will also result in a lower grade.
The laboratory sessions will be in the 3rd floor Simulation Laboratory on Wednesdays from 10:00AM to
12:00PM. Scores achieved for PBL cases, daily quizzes, mid-term and final examinations and laboratory
projects will be totaled at the end of the course to provide the final grade. Students must take the mid-term
and final examinations and submit all required laboratory projects. Laboratory projects that do not achieve
50% or better will need to be redone until a satisfactory grade is achieved. The relative weighting of scores
will be:
Daily quizzes and PBL evaluations 20%
Mid-term Examination 20%
Final Examination 20%
Required Laboratory Projects 40% (Total)
Palatal Expander (10%)
Study Models (10%)
Thumb Hawley (10%)
Cephalometric Tracing (10%)
VIII. BOARD PREPARATION
Course topics are immediately relevant to examination areas of the National Board Exams.
Emphasis will be placed on National Board examination subjects. Two preparatory and review sessions are
provided.
31
USC School of Dentistry 4
th
year Survey Results
Surveys were collected from 102 out of the 144 total 4
th
year USC D.D.S.
students. Descriptive statistics are presented in Tables 1-3.
Survey statements 1-15 (S1-S15) were recorded as either a valid response or
missing in Tables 1 and 2. The mean, median, and standard deviation are also listed for
each statement in Tables 1 and 2.
Table 1: USC Survey statements 1-7
USC S1 S2 S3 S4 S5 S6 S7
N Valid
102 102 102 102 102 102 101
Invalid/
Missing
0 0 0 0 0 0 1
Mean
3.56 3.49 2.88 2.95 2.58 2.58 3.21
Median
4.00 3.50 3.00 3.00 3.00 2.50 3.00
Std. Deviation
.725 .686 .824 .801 .895 .895 .875
Percentiles 25
3.00 3.00 2.00 2.00 2.00 2.00 3.00
50
4.00 3.50 3.00 3.00 3.00 2.50 3.00
75
4.00 4.00 3.00 3.00 3.00 3.00 4.00
Table 2: USC Survey Statements 8-15
To test for differences between groups of statements, we grouped the statements
in four groups: statements 1-2 deal with occlusion; 3-7 deal with orthodontic diagnosis;
8- 9 deal with basic orthodontic principles; and 10-15 deal with orthodontic treatment.
Descriptive statistics are presented in Table 4. We compared the level of confidence
USC S8 S9 S10 S11 S12 S13 S14 S15
N Valid
102 101 102 100 102 101 102 101
Invalid/
Missing
0 1 0 2 0 1 0 1
Mean
3.26 3.12 3.55 3.25 2.94 3.05 2.59 2.62
Median
3.00 3.00 4.00 3.00 3.00 3.00 2.00 3.00
Std. Deviation
.889 .941 .875 .989 .921 .753 .927 1.018
Percentiles 25
3.00 3.00 3.00 3.00 2.00 3.00 2.00 2.00
50
3.00 3.00 4.00 3.00 3.00 3.00 2.00 3.00
75
4.00 4.00 4.00 4.00 4.00 4.00 3.00 3.00
32
among USC DDS students between two groups of statements using the Wilcoxon Signed
Ranks test.
To adjust for multiple testing we used the Bonferroni correction with
alpha=0.05/6=0.008, with 6 pairs of comparisons between the 4 groups of statements
(orthodontic treatment, orthodontic diagnosis, orthodontic principles and occlusion).
Table 3: USC Statement Groupings
USC occlusion
Ortho
diagnosis
Ortho
principles
Ortho
principles
N Valid
102 101 101 98
Invalid/Missing
0 1 1 4
Mean
3.5245 2.8455 3.1931 3.0119
Median
3.5000 2.8000 3.0000 3.0000
Std. Deviation
.61892 .58095 .85431 .65201
Range
3.00 2.60 4.00 3.17
There were statistically significant differences in level of confidence between the
four groups of statements (orthodontic treatment, orthodontic diagnosis, orthodontic
principles and occlusion) among the DDS students (p<.001) according to the Friedman’s
test.
There were statistically significant differences in level of confidence between
occlusion and orthodontic diagnosis (p<.001), occlusion and basic orthodontic principles
(p<.001), occlusion and orthodontic treatment (p<.001), orthodontic principles and
orthodontic diagnosis (p<.001), orthodontic treatment and orthodontic diagnosis
(p=.007), orthodontic treatment and orthodontic principles (p=.032).
After Bonferroni correction (alpha=0.05/6=.008), there were significant
differences in level of confidence between occlusion and orthodontic diagnosis (p<.001),
33
occlusion and basic orthodontic principles (p<.001), occlusion and orthodontic treatment
(p<.001), orthodontic principles and orthodontic diagnosis (p<.001), orthodontic
treatment and orthodontic diagnosis (p=.007).
Clinical specialty confidence rankings are recorded in Table 4 as either a valid
response or as missing or invalid. The mean, median, and standard deviation for each
specialty’s total rankings are also listed in Table 4. Responses were recorded as invalid if
the respondent marked any one of the rankings (#1-#6) more than once.
To test for differences in clinical confidence among DDS students between the six
specialties, we used the non-parametric Friedman’s test. To test for differences in clinical
confidence among DDS students between two specialties, we used the non-parametric
Wilcoxon Rank Sum test. To adjust for multiple testing we used the Bonferroni
correction with alpha=0.05/15=0.003, with 15 pairs of comparisons between levels of
confidence in the different specialties.
Histograms with normal growth curves for the 6 clinical specialties are depicted
in Figures 5-10.
Table 4: USC Clinical specialty rankings
USC Endo. Oral surgery Ortho. Pedo. Perio. Prosth.
N Valid
66 66 66 66 66 66
Invalid/Missing
36 36 36 36 36 36
Mean
3.03 3.53 5.76 3.06 2.92 2.67
Median
3.00 4.00 6.00 3.00 3.00 2.00
Std. Deviation
1.414 1.459 .583 1.497 1.460 1.512
Percentiles 25
2.00 3.00 6.00 2.00 2.00 1.00
50
3.00 4.00 6.00 3.00 3.00 2.00
75
4.00 5.00 6.00 4.00 4.00 4.00
34
There was a statistically significant difference in clinical confidence among the
USC D.D.S. students (p<.001) according to the non-parametric Friedman’s test.
There was a statistically significant difference in clinical confidence among the
USC D.D.S. students between orthodontics and endodontics (p<.001), orthodontics and
oral surgery (p<.001), orthodontics and pedodontics (p<.001), orthodontics and
periodontics (p<.001), orthodontics and prosthodontics (p<.001), periodontics and oral
surgery (p=.032) and prosthodontics and oral surgery (p=.007) according to the Wilcoxon
Signed Ranks Tests.
After Bonferroni correction (alpha = 0.05/15=.003), the following comparisons
were statistically significant: ortho and endo (p<.001), ortho and oral surgery (p<.001),
ortho and pedo (p<.001), ortho and perio (p<.001), and ortho and pros (p<.001),
Figure 5: Plots total USC student
respondents (Y-axis) versus
numerical ranking of confidence
in Enodontics (X-axis)
0 1 2 3 4 5 6 7
endo
0
5
10
15
20
Frequency
Mean = 3.03
Std. Dev. = 1.414
N = 66
endo
35
Figure 6: Plots total USC
student respondents (Y-axis)
versus numerical ranking of
confidence in Oral Surgery (X-
axis)
Figure 7: Plots total
USC student
respondents (Y-axis)
versus numerical
ranking of confidence in
Orthodontics (X-axis)
0 1 2 3 4 5 6 7
oralsurg
0
5
10
15
20
Frequency
Mean = 3.53
Std. Dev. = 1.459
N = 66
oralsurg
2 3 4 5 6 7
ortho
0
10
20
30
40
50
60
Frequency
Mean = 5.76
Std. Dev. = 0.583
N = 66
ortho
36
Figure 8: Plots total USC
student respondents (Y-axis)
versus numerical ranking of
confidence in pedodontics (X-
axis)
Figure 9: Plots total USC
student respondents (Y-axis)
versus numerical ranking of
confidence in Periodontics
(X-axis)
0 1 2 3 4 5 6 7
pedo
0
5
10
15
20
Frequency
Mean = 3.06
Std. Dev. = 1.497
N = 66
pedo
0 1 2 3 4 5 6 7
perio
0
5
10
15
20
Frequency
Mean = 2.92
Std. Dev. = 1.46
N = 66
perio
37
Figure 10: Plots total USC
student respondents (Y-axis)
versus numerical ranking of
confidence in Prosthodontics
(X-axis)
0 1 2 3 4 5 6 7
pros
0
5
10
15
20
Frequency
Mean = 2.67
Std. Dev. = 1.512
N = 66
pros
38
Figure 11: XYZ Dental School Undergraduate Orthodontics Syllabus
Session 1 Assignment
Tuesday 1/29/2008
8:00-Noon Malocclusion and Dentofacial Deformity Chapter 1 (3-23)
Concepts of Growth and Development Chapter 2 (27-70)
1:00-5:00 Early Stages of Development Chapter 3 (72-103)
Session 2
Monday A.M. Only 2/4/2008
9:00-Noon Quiz #1
Later Stages of Development Chapter 4 (107-128)
The Etiology of Orthodontic Problems Chapter 5 (130-160)
Orthodontic Diagnosis:
The Development of a Problem List Chapter 6 (167-200,
229
Session 3
Tuesday 2/5/2008
8:00-Noon Quiz #2
Cephalometric Landmarks Chapter 6 (201-218)
Handouts
1:00-5:00 Cephalometric Tracing Exercise-Sim Clinic Handouts
Session 4
Wednesday A.M. Only 2/6/2008
8:00-Noon Quiz #3
Orthodontic Classification Chapter 6 (218-229)
Orthodontic Treatment Planning: From
Problem List to Specific Planning Chapter 7 (234-250)
The Biologic Basis of Orthodontic Therapy Chapter 9 (331-358)
Session 5
Thursday 2/7/2008
8:00-Noon Comprehensive Treatment Planning Chapter 18 (635-651)
Dr. Sanchez Handout
Mechanical Principles in Orthodontic Force Control Chapter 10 (359-393)
Contemporary Orthodontic Appliances Chapter 11 (395-429)
1:00-5:00 Laboratory Exercise-Fabrication of a LLHA-Sim Clinic
Session 6
Friday 2/8/2008
8:00-Noon Treatment of Nonskeletal Problems in
Preadolescent Children Chapter 12 (433-493)
Retention Chapter 17 (617-631)
1:00-5:00 Laboratory Exercise-Fabrication of a Hawley Retainer-Sim Clinic
39
XYZ Dental School 4
th
year Survey Results
Surveys were collected from 22 out of the 55 total 4
th
year XYZ dental students.
Descriptive statistics are presented in Tables 5-7.
Survey statements 1-15 (S1-S15) were recorded as either a valid response or
missing in Tables 5 and 6. The mean, median, and standard deviation are also listed for
each statement in Tables 5 and 6.
Table 5: XYZ Survey Statements 1-7
XYZ S1 S2 S3 S4 S5 S6 S7
N Valid
22 22 22 22 22 22 22
Invalid/
Missing
0 0 0 0 0 0 0
Mean
3.27 3.27 2.86 3.09 2.45 2.55 2.18
Median
3.00 3.00 3.00 3.00 2.00 2.00 2.00
Std. Deviation
.827 .767 .774 .750 .739 .858 .853
Range
4 3 3 3 3 4 3
Percenti
les
25
3.00 3.00 2.00 3.00 2.00 2.00 1.75
50
3.00 3.00 3.00 3.00 2.00 2.00 2.00
75
4.00 4.00 3.00 4.00 3.00 3.00 3.00
Table 6: XYZ Survey Statements 8-15
XYZ S8 S9 S10 S11 S12 S13 S14 S15
N Valid
22 22 22 22 22 22 21 22
Invalid/Mi
ssing
0 0 0 0 0 0 1 0
Mean
3.09 2.55 3.23 3.05 2.32 3.18 2.19 2.27
Median
3.00 2.50 3.00 3.00 2.00 3.00 2.00 2.00
Std. Deviation
.921 .739 .813 .899 .995 .853 .680 .703
Range
4 3 3 3 3 3 2 3
Percent
iles
25
3.00 2.00 3.00 3.00 1.75 3.00 2.00 2.00
50
3.00 2.50 3.00 3.00 2.00 3.00 2.00 2.00
75
4.00 3.00 4.00 4.00 3.00 4.00 3.00 3.00
40
To test for differences between groups of statements, we grouped the statements
in four groups: statements 1-2 deal with occlusion; 3-7 deal with orthodontic diagnosis;
8- 9 deal with basic orthodontic principles; and 10-15 deal with orthodontic treatment.
Descriptive statistics are presented in Table 7. We compared the level of confidence
among DDS students between the groups of statements with the Friedman’s test. We
compared the level of confidence between two groups of statements using the Wilcoxon
Signed Ranks test.
To adjust for multiple testing we used the Bonferroni correction with
alpha=0.05/6=0.008, with 6 pairs of comparisons between the 4 groups of statements
(orthodontic treatment, orthodontic diagnosis, orthodontic principles and occlusion).
Table 7: XYZ Statement Groupings
XYZ occlusion
Ortho
diagnosis Ortho principles
Ortho
treatment
N Valid
22 22 22 22
Missing
0 0 0 0
Mean
3.2727 2.6273 2.8182 2.6900
Median
3.5000 2.6000 3.0000 2.7500
Std. Deviation
.71925 .62426 .74874 .64078
Range
3.50 3.20 3.50 2.50
There were statistically significant differences in level of confidence between the
four types of statements (occlusion, orthodontic diagnosis, orthodontic treatment, and
orthodontic principles) among the DDS students (p<.001) according to the Friedman’s
test.
41
There were statistically significant differences in level of confidence between
occlusion and orthodontic diagnosis (p<.001), occlusion and basic orthodontic principles
(p=.015), occlusion and orthodontic treatment (p=.001).
After Bonferroni correction (alpha=0.05/6=.008), there were significant
differences in level of confidence between occlusion and orthodontic diagnosis (p<.001)
and occlusion and orthodontic treatment (p=.001).
To test for differences in clinical confidence among DDS students between the six
specialties, we used the non-parametric Friedman’s test. Descriptive statistics are
presented in Table 8. To test for differences in clinical confidence among DDS students
between two specialties, we used the non-parametric Wilcoxon Rank Sum test. To adjust
for multiple testing we used the Bonferroni correction with alpha=0.05/15=0.003, with 15
pairs of comparisons between level of confidence in the different specialties.
Histograms with normal growth curves for the 6 clinical specialties are depicted
in Figures 12-17.
Table 8: XYZ Clinical Specialty Rankings
XYZ endo Oralsurg ortho pedo Perio pros
N Valid
20 20 20 20 20 20
Invalid/Missing
2 2 2 2 2 2
Mean
3.70 1.60 5.55 2.75 3.45 3.80
Median
4.00 1.00 6.00 3.00 3.00 4.00
Std. Deviation
1.342 .883 1.050 1.251 1.276 1.436
Range
4 3 4 4 4 5
Perc
entil
es
25
3.00 1.00 6.00 2.00 2.25 3.00
50
4.00 1.00 6.00 3.00 3.00 4.00
75
5.00 2.00 6.00 3.00 5.00 4.75
42
There was a statistically significant difference in clinical confidence among the
DDS students (p<.001) according to the non-parametric Friedman’s test.
There was a statistically significant difference in clinical confidence among the
DDS students between orthodontics and endodontics (p<.001), orthodontics and oral
surgery (p<.001), orthodontics and pedodontics (p<.001), orthodontics and periodontics
(p=.001), orthodontics and prosthodontics (p=.004), endodontics and oral surgery
(p=.001), pedodontics and oral surgery (p=.006), periodontics and oral surgery (p<.001)
and prosthodontics and oral surgery (p=.001), and prosthodontics and pedodontics
(p=.024) according to the Wilcoxon Signed Ranks Tests.
After Bonferroni correction (alpha = 0.05/15=.003), the following comparisons
were statistically significant: orthodontics and endodontics (p<.001), orthodontics and
oral surgery (p<.001), orthodontics and pedodontics (p<.001), orthodontics and
periodontics (p=.001), endodontics and oral surgery (p=.001), periodontics and oral
surgery (p<.001) and prosthodontics and oral surgery (p=.001).
43
0 1 2 3 4 5 6
endo
0
1
2
3
4
5
6
7
Frequency
Mean = 3.7
Std. Dev. = 1.342
N = 20
endo
Figure 12: Plots total XYZ student respondents (Y-axis) versus numerical ranking of confidence in
Enodontics (X-axis)
0 1 2 3 4 5
oralsurg
0
2
4
6
8
10
12
Frequency
Mean = 1.6
Std. Dev. = 0.883
N = 20
oralsurg
Figure 13: Plots total XYZ student respondents (Y-axis) versus numerical ranking of confidence in
Oral Surgery (X-axis)
44
1 2 3 4 5 6 7
ortho
0
5
10
15
20
Frequency
Mean = 5.55
Std. Dev. = 1.05
N = 20
ortho
Figure 14: Plots total XYZ student respondents (Y-axis) versus numerical ranking of confidence in
Orthodontics (X-axis)
0 1 2 3 4 5 6
pedo
0
1
2
3
4
5
6
7
Frequency
Mean = 2.75
Std. Dev. = 1.251
N = 20
pedo
Figure 15: Plots total XYZ student respondents (Y-axis) versus numerical ranking of confidence in
Pedodontics (X-axis)
45
0 1 2 3 4 5 6
perio
0
1
2
3
4
5
6
7
Frequency
Mean = 3.45
Std. Dev. = 1.276
N = 20
perio
Figure 16: Plots total XYZ student respondents (Y-axis) versus numerical ranking of confidence in
Periodontics (X-axis)
0 1 2 3 4 5 6 7
pros
0
2
4
6
8
Frequency
Mean = 3.8
Std. Dev. = 1.436
N = 20
pros
Figure 17: Plots total XYZ student respondents (Y-axis) versus numerical ranking of confidence in
Prosthodontics (X-axis)
46
Discussion
The primary purpose of this study was to gauge the orthodontic confidence levels
of senior dental students from the University of Southern California (USC) School of
Dentistry and one other US dental school (XYZ Dental School) whom have completed
the necessary courses that their respective schools require them to pass in order to be
eligible recipients of the D.D.S. degree. With the growth in the total amount of
orthodontic treatment being done by general practitioners as compared to treatment done
by certified orthodontists, we hypothesized that dental students today graduate with a
high level of confidence in concepts of orthodontic principles, occlusion, diagnosis, and
treatment planning, and feel high confidence in clinical orthodontics as compared to the
other clinical dental specialties.
The undergraduate orthodontics course at USC is taught over 3 trimesters during
the student’s 3
rd
year in the program. During the first two semesters the students meet
once a week for 4 hours and the time is equally shared between 2 hours of PBL and
lecture and 2 hours of hands on simulation lab work (a total of over 40 hours each).
During the third trimester, the students meet 3 times for 2 hours each in a hands-on molar
uprighting simulation lab exercise. As stated in the course description within the
syllabus, the course is an introduction for the general practitioner in the evaluation,
prevention, and treatment of dentofacial malformations. Fundamentals of dental
development, etiologies of malocclusion, somatic and craniofacial growth and
development, biology of tooth movement, osteology, and radiology are emphasized.
47
Students are taught how to construct the basic appliances used to treat orthodontic
problems encountered in a general practice (see Figure 4).
The undergraduate orthodontics course at XYZ Dental School is taught over the
course of 2 weeks and includes 28 hours of lecture and 3 four hour hands-on simulation
lab exercises including cephalometric tracing and fabrication of a lower lingual holding
arch and a Hawley retainer (see Figure 11).
When the 15 confidence statements on the survey were grouped into categories,
the USC students showed mean levels of confidence nearest to a value of “moderate
confidence” (3) for each group except “occlusion” which was given the highest relative
level of confidence with a mean of 3.5245. The “orthodontic diagnosis” grouped
statements had the lowest relative confidence with a mean of 2.8, this being the only
statement group that averaged below a 3.
The XYZ students when compared to USC students showed lower levels of
confidence in all 4 statement groupings, but still also showed mean levels of confidence
nearest to a value of “moderate confidence” (3) for each group. Again, as with the USC
respondents, the XYZ students showed highest confidence in the “occlusion” group
(mean of 3.2727) and the lowest relative level of confidence in the “orthodontic
diagnosis” group (mean of 2.6273). The “occlusion” statement group was the only one to
average above a 3 for the XYZ students.
Overall it seems that the USC students, having benefited from a more extensive
undergraduate orthodontic course, show a higher level of confidence in this field as
48
compared to the XYZ students who had a less extensive undergraduate orthodontic
course provided to them.
One conflicting finding in both the USC and XYZ data was that students showed
one of the highest responses of confidence (USC mean of 3.55, XYZ mean of 3.23) in
statement #10, “I understand the goals of standard orthodontic treatment”, and one of the
lowest responses of confidence (USC mean of 2.62, XYZ mean of 2.27) in statement #15,
“I am able to evaluate and critique a finished orthodontic case.” It would seem that
someone who understood the goals of treatment should be able to evaluate the end
product of treatment once those goals have been supposedly met.
Despite the fact that the USC students were specifically instructed on palatal
expansion, molar uprighting, and other limited dental movements through lectures, PBL
sessions, and even sim-lab practice, they still only expressed moderate confidence (mean
of 2.94) to statement #12 which addressed those specific treatments.
Both USC and XYZ students responded particularly low in confidence to
statement #14, “I understand the strengths and limitations of different appliances
(standard brackets, invisalign, lingual braces, etc).” One could make the argument that
this specific lack of confidence is why general practitioners are sometimes easily
misinformed and misled by dental companies who push exaggerated claims on certain
appliances and types of treatment, leading to poor case selection and problems for the
doctor.
In regards to the final item on the survey, the clinical confidence rankings of the 6
different specialties, it was clear that both schools felt similar about where orthodontics
49
stood. The USC students ranked orthodontics last amongst the specialties with a mean
rank of 5.76. The XYZ students ranked orthodontics last amongst the specialties with a
mean rank of 5.55.
Limitations
A respondents self-assessed level of confidence should not be confused with that
persons true knowledge or capability in the subject in question. A student with low
confidence may actually have a high degree of knowledge in that area and vice versa.
Also, we cannot assume that the level of confidence accurately correlates with which
students will provide more or less orthodontic treatment as general practitioners.
There were a total of 36 out of 102 USC respondents to the final clinical specialty
ranking item that had to be considered “missing/invalid” due to the fact that they used
one or more of the choice numbers (1-6) more than once. This was the fault of the author
for not clearly specifying that each rank should be used just once. In the XYZ version of
the survey on “surveymonkey.com” this adjustment was specified and the result was that
only two students did not mark the item with a valid response.
Likert scales may be subject to distortion from several causes. Respondents may
avoid using extreme response categories (central tendency bias); agree with statements as
presented (acquiescence bias); or try to portray themselves or their organization in a more
favorable light (social desirability bias). Perhaps designing a scale with a more balanced
keying (an equal number of positive and negative statements) could have obviated the
potential of acquiescence bias, since acquiescence on positively keyed items will balance
50
acquiescence on negatively keyed items, but central tendency and social desirability are
somewhat more problematic.
One could also make the argument that it would have been better to place the final
clinical specialty ranking item on the top of the survey, in front of the 15 confidence
statements. After going through the first 15 statements pertaining to orthodontics, the
student might be more acutely aware of his or her relative lack of knowledge in this
subject area and might be more inclined to rank orthodontics lower than if he did not read
the 15 confidence statements to begin with.
Conclusion
With the trend of increasing orthodontic treatment being provided by general
practitioners, we put forth the hypothesis that today’s dental students graduate with a high
level of confidence in concepts of orthodontic principles, occlusion, diagnosis, and
treatment planning, and feel high confidence in clinical orthodontics as compared to the
other clinical dental specialties. Our results showed that the 4
th
year dental students
surveyed assessed themselves on having a “moderate confidence” level in the majority of
survey statements. The students felt the strongest level of confidence in statements
addressing “occlusion” and the lowest levels in those statements addressing “orthodontic
diagnosis”. The USC students were exposed to an undergraduate orthodontic course that
was more extensive in regards to course hours, hands-on sim-lab time, and subject
material covered, and did subsequently show higher levels of confidence than the XYZ
students across the board. In regards to ranking the clinical specialties according to
confidence, both groups of students gave orthodontics the lowest markings.
51
General practitioners providing a large and growing proportion of the total
orthodontic treatment provided will continue to be a controversial subject. Future
research is needed to answer some important questions. Of patients treated by non-
orthodontists, what proportion are treated successfully by orthodontic standards? Has the
quality of orthodontic care provided by non-specialists improved in the last 10 years? Are
practitioners without graduate orthodontic training often content to do orthodontics with
standards different than those of the orthodontic specialist? Why will some individual
practitioners accept compromised orthodontic treatment when they insist on ideal
standards in restorative work of even the most challenging type? Is it really possible to
believe that private practitioners will hold the specialty of orthodontics in high regard if
they accept compromised results in the orthodontic care they provide?
52
References
Adamidis, JP. A survey of undergraduate orthodontic education in 23 European
countries, British Journal of Orthodontics, 27(1), 84-91, 2000.
Aiken, LR. The problem of nonresponse in survey research. Journal of Experimental
Education, 56(3), 116-119, 1988
Aly, M. Instructional multimedia programs for self-directed learning in
undergraduate and postgraduate training in orthodontics, European Journal of Dental
Education, 7(1), 20-26, 2003.
Armstrong, JS. Monetary incentives in mail surveys. The Public Opinion Quarterly,
39, 111-116.
Babbie, E. Survey Research Methods, 2
nd
edition, Wadsworth 1990.
Borg, WR, Gall, MD. Educational research, 5
th
edition, Longman, 1989.
Chadwick, S. Orthodontic undergraduate education: developments in a modern
curriculum, European Journal of Dental Education, 6, 57-63, 2002.
Cohen, Louis. Research Methods in Education, 6
th
edition, Routledge 2007.
Dawes, John. Do Data Characteristics Change According to the number of scale
points used? An experiment using 5-point, 7-point and 10-point scales. International
Journal of Market Research, 50(1), 61-67, 2008
de Leeuw, ED. Data quality in mail, telephone, and face to face surveys, Netherlands
Organization for Scientific Research, 1992.
Deming, WE. Sample design in business research, John Wiley and Sons 1960.
Derringer, KA. Undergraduate orthodontic teaching in UK dental schools, British
Dental Journal, 199(4), 224-32, 2005
Dillman, DA. The design and administration of mail surveys. Annual Review of
Sociology, 17, 225-249, 1991.
Hedayat AS, & Sinha BK. Design and inference in finite population sampling,
Wiley, 1991.
Hmelo-Silver, C. E. (2004). Problem-based learning: What and how do students
learn? Educational Psychology Review, 16(3), 235-266.
53
Hmelo-Silver, C. E. & Barrows, H. S. (2006). Goals and strategies of a problem-
based learning facilitator. Interdisciplinary Journal of Problem-based Learning, 1. 21-
39.
Johnson, EG. The design of the National Assessment of Educational Progress.
Journal of Educational Measurement, 29(2), 95-110.
Jollifie, FR. Survey design and analysis, John Wiley and Sons, 1986.
Kindelan, J. A study to determine if changes to an undergraduate orthodontic course
improved course quality and student satisfaction, European Journal of Dental
Education, 1(3), 138-42, 1997.
Kish, L. Survey Sampling, John Wiley and Sons, 1965
Koh, Khoo, Wong, & Koh, The effects of problem-based learning during medical
school on physician competency: a systematic review, 2008
Lee, ES, Forthofer, RN, & Lorimor, RJ. Analyzing complex survey data, Sage 1989.
Lin, L, & Schaeffer, NC. Using survey participants to estimate the impact of
nonparticipation. The Public Opinion Quarterly, 59(2) 236-258.
Mcnamara, JF. Surveys and experiments in education research, Technomic, 1994
O’Brien, K. Undergraduate orthodontic education: what should we teach rather than
what can we teach?, British Journal of Orthodontics, 333-334, 1997.
Pena, DM & Henderson, RD. Sampling procedures used for national surveys of
public school teachers – problems and possible solutions. American Educational
Research Association, presented 1986.
ProQuest File. Dissertation Abstracts: January 1993-June 1995. [CD-ROM], 1995.
Rock, W. Orthodontic teaching practice and undergraduate knowledge in British
dental schools, British Dental Journal, 192(6), 347-351, 2002.
Rosier, M. J. "Survey Research Methods" in Keeves J (Eds) Educational Research,
Methodology, and Measurement: An International Handbook, Second Edition.
Pergamon, Cambridge: University Press, 1997
Sapsford, Roger. Survey Research, 2
nd
edition, Sage 2006.
54
Schaeffer, RL, Mendenhall, W, & Ott, L. Elementary survey sampling, 4
th
edition,
PWS-Kent, 1990.
Shultz, SD, & Luloff, AE. The threat of nonresponse bias to survey research.
Journal of the Community Development Society, 21(2), 104-115.
Sweller, J. "Cognitive load during problem solving: Effects on learning". Cognitive
Science 12 (2): 257–285, 1988.
Sweller, J. "The worked example effect and human cognition". Learning and
Instruction 16 (2): 165–169, 2006.
Sweller, J., Van Merrienboer, J., & Paas, F. "Cognitive architecture and instructional
design". Educational Psychology Review 10: 251–296, 1998.
Wang, Lin. An evaluation of the sample designs in educational research. American
Educational Research Association, presented 1997
Wilson, BG. Constructivist learning environments: case studies in instructional
design, Educational Technology Publications, 1996.
Wright, CP. Status of Orthodontic Education prior to 1930. Angle Orthodontist.
17:92-96,1947. 4.
Yates, Frank. Sampling methods for censuses and surveys, 3
rd
edition, Londo Charles
Griffin & Company, 1960.
Zanutto, EL. Jacknife variance estimation under imputation for missing survey data.
Abstract from ProQuest File, 1993
Abstract (if available)
Abstract
The purpose of the study was to gauge the orthodontic confidence levels of senior dental students from the University of Southern California (USC) School of Dentistry and one other US dental school (which will be referred to as XYZ Dental School) whom have completed the necessary courses that their respective schools require them to pass in order to be eligible recipients of the D.D.S. degree. This study examines teaching contents and time allocation within the undergraduate orthodontic curriculum at both schools, as well as a survey, filled out by their senior dental students whom have successfully completed such courses, concerning their confidence in a variety of orthodontic concepts and treatment. The course directors at each school were contacted and interviewed in detail about the nature of the course. A paper survey questionnaire was distributed to each of the 144 members of the USC D.D.S. Class of 2010. Senior dental students at XYZ Dental School were contacted through email and asked to fill out an electronic copy of the survey posted on the website “Survey Monkey” (surveymonkey.com). Results indicated that the 4th year dental students surveyed assessed themselves as having a “moderate confidence” level in the majority of survey statements. The students felt the strongest level of confidence in statements addressing “occlusion” and the lowest levels in those statements addressing “orthodontic diagnosis”. In regards to ranking the clinical specialties according to confidence, both groups of students gave orthodontics the lowest markings.
Linked assets
University of Southern California Dissertations and Theses
Conceptually similar
PDF
Mandibular plane angle changes with or without premolar extraction treatment in adult orthodontics measured using 3-D cone beam technology
PDF
A comparison of root resorption between Invisalign treatment and contemporary orthodontic treatment
PDF
Proper mesio-distal angulation and bucco-lingual inclination of the whole tooth in three-dimensional space -- a standard for orthodontic patients
PDF
Cirtual 3D placement of temporary orthodontic anchorage implants
PDF
Sexual differences and early eruption timing of the permanent dentition in Mexican adolescents- a comparison with the Caucasian standards
PDF
Orthodontic rotational relapse: prevalence and prevention
PDF
Comparison between tooth mesiodistal angulation measurements from constructed panoramic images and three-dimensional volumetric images
PDF
Long-term dental stability of cases with an uncorrected anterior tooth-size discrepancy
PDF
Effect of cyclooxygenase inhibitors on rat root resorption and tooth movement
PDF
A cone beam-CT evaluation of the availability of space for complete arch retraction in the mandible with TADs
PDF
A cone beam CT evaluation of the maxillary dento skeletal complex after rapid palatal expansion
PDF
Use of digital models to assess orthodontic treatment progress
PDF
The correlation between dental caries in primary and permanent teeth in children at two different elementary schools
PDF
Bonding accuracy of a novel lingual customized orthodontic appliance (INBRACE™): an in-vivo study
PDF
The effectiveness of practice management education in orthodontic residencies: the alumni's perspective
PDF
3D assessment of virtual bracket removal for modern orthodontic retainers: a prospective clinical study
PDF
The effect of cone beam computed tomography (CBCT) imaging on orthodontic diagnosis and treatment planning
PDF
Three-dimensional assessment of tooth root shape and root movement after orthodontic treatment: a retrospective cone-beam computed tomography study
PDF
Comparison of premolar extraction rates between one-phase and two-phase class II malocclusion
PDF
Comparison of self-ligating brackets to conventionally-ligated twin edgewise brackets for root resorption
Asset Metadata
Creator
Foster, Chad Richard
(author)
Core Title
Orthodontic confidence of senior dental students: a study of 2 US dental schools
School
School of Dentistry
Degree
Master of Science
Degree Program
Craniofacial Biology
Degree Conferral Date
2010-05
Publication Date
05/05/2010
Defense Date
03/26/2010
Publisher
University of Southern California
(original),
University of Southern California. Libraries
(digital)
Tag
confidence,education,OAI-PMH Harvest,orthodontic,predoctoral,survey,undergraduate
Place Name
USA
(countries)
Language
English
Contributor
Electronically uploaded by the author
(provenance)
Advisor
Sameshima, Glenn T. (
committee chair
), Moon, Holly (
committee member
), Paine, Michael (
committee member
)
Creator Email
chadfosterdds@gmail.com,crfoster@usc.edu
Permanent Link (DOI)
https://doi.org/10.25549/usctheses-m3023
Unique identifier
UC1480946
Identifier
etd-Foster-3660 (filename),usctheses-m40 (legacy collection record id),usctheses-c127-331466 (legacy record id),usctheses-m3023 (legacy record id)
Legacy Identifier
etd-Foster-3660.pdf
Dmrecord
331466
Document Type
Thesis
Rights
Foster, Chad
Type
texts
Source
University of Southern California
(contributing entity),
University of Southern California Dissertations and Theses
(collection)
Repository Name
Libraries, University of Southern California
Repository Location
Los Angeles, California
Repository Email
cisadmin@lib.usc.edu
Tags
confidence
education
orthodontic
predoctoral
survey
undergraduate