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Quality of reporting of observational studies in periodontology and implant dentistry: a cross-sectional survey

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Quality of reporting of observational studies in periodontology and implant dentistry: a cross-sectional survey

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Content
QUALITY OF REPORTING OF OBSERVATIONAL STUDIES
IN PERIODONTOLOGY AND IMPLANT DENTISTRY-
A CROSS-SECTIONAL SURVEY

By
Sarah Bushehri

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)
August 2015

Copyright 2015 Sarah Bushehri
ii
DEDICATION

To my parents and friends for their unconditional love, support and
encouragement.

iii
ACKNOWLEDGEMENTS

My deepest gratitude goes to my faculty, colleagues and friends at the University of
Southern California who made this thesis possible. First and foremost, I would like to
thank Dr. Kian Kar for his infinite support, patience and mentoring for the past four
years. Thank you for believing in me when I doubted my own self. Your passion and hard
work is inspiring and I am honored to have worked with a great leader like you.
Thank you to Dr. Satish Kumar for allowing me to be part of this incredible
experience. Thank you for your guidance, support and mentoring throughout this project.
You are exceptionally talented and your ideas have influenced me and many others. I
appreciate our many hours of discussions and your dedication and contributions devoted
to this manuscript.
I also would like to thank my colleague Dr. Husain Mohammad for being a great
friend, who was really there for me in the good times and the bad times. Your support
and encouragements along the way will always be remembered.
Last but not least, I would like to thank my committee members Dr. Michael
Paine and Dr. Glenn Sameshima who contributed by serving as committee members.
Thank you to our Program Director Dr. Homa Zadeh for his care and guidance through
out my graduate program.

iv
TABLE OF CONTENTS

Dedication ii
Acknowledgements iii
List of Appendices v
List of Figures vi
Abstract 1
Chapter 1: Introduction & Background 4
Chapter 2: Materials & Methods 14
Chapter 3: Results 19
Chapter 4: Discussion 35
Chapter 5: Conclusion 42
Bibliography 43
Appendix A 54
Appendix B 57
Appendix C 62
Appendix D 68

v
LIST OF APPENDICES

Appendix A The Strengthening of Reporting of Observational Studies in
Epidemiology (STROBE) Original checklist- for cohort, case-
control, and cross-sectional studies (combined)

Appendix B The Strengthening of Reporting of Observational Studies in
Epidemiology (STROBE) Modified checklist- for cohort, case-
control, and cross-sectional studies (combined)

Appendix C Eligible Studies Included In The Analysis
Appendix D List of Excluded Articles and Reason for Exclusion

vi
LIST OF FIGURES

Figure 1 Classification of common clinical research designs
Figure 2 Schematic diagram showing cohort study design
Figure 3 Schematic diagram showing case-control study design
Figure 4 Flow chart of search strategy
Figure 5 Flow chart of included studies based on study design
Figure 6 Percentage of adherence of all articles to the STROBE checklist
Figure 7 Distribution of adherence of all papers to STROBE checklist
Figure 8 Mean percentage of adherence of all papers based on different
study designs
Figure 9 Mean Percentage of adherence to STROBE checklist items 1, 2, and
3 per study design

Figure 10 Mean Percentage of adherence to STROBE checklist items 4, 5, 6,
and 7 per study design
Figure 11 Mean Percentage of adherence to STROBE checklist items 8, 9, 10
and 11 per study design
Figure 12 Mean Percentage of adherence to STROBE checklist item 12 per
study design
Figure 13 Mean Percentage of adherence to STROBE checklist items 13 and
14 per study design

Figure 14 Mean Percentage of adherence to STROBE checklist items 15, 16
and 17 per study design

Figure 15 Mean Percentage of adherence to STROBE checklist items 18, 19,
20, 21 and 22 per study design

Figure 16 Mean percentage of adherence of all papers per checklist item
1
ABSTRACT

BACKGROUND
As of today, the majority of the evidence to support clinical periodontal practice
and implant dentistry is derived from observational studies. However, interpretation of
data from observational studies in the periodontal literature is often limited by suboptimal
quality of reporting. The need for transparent reporting of scientific research in general
led to influential statements and the development of guidelines to direct researchers and
improve the quality of reporting studies.
Since the development of STROBE statement in 2007, there have been attempts
to improve the quality of reporting of observational studies published in periodontal
journals. However, it is still not clear which items from the statement are well reported
and which items requires further improvement.

AIM
The aim of this study was to conduct a cross sectional survey on the quality of
reporting on published analytical observational studies in one of the major journals in
periodontology using a modified checklist of the STROBE statement. The most recent
issues published in a journal with the highest impact factor (IF) in periodontology and
implant dentistry, the Journal of Clinical Periodontology, were reviewed. The focused
question was: what is the quality of reporting of observational studies in periodontology
and implant dentistry in Journal of Clinical Periodontology?

2
METHODS
An online search using MEDLINE followed by hand search of JCP was
performed to identify observational studies published between January 01, 2014 and
December 31, 2014.
Inclusion criteria: analytical human observational studies (cohort, case-control and
cross-sectional). All experimental studies or articles reporting on case series/reports,
animal /cadaver studies, and in vitro studies were excluded. In addition, systematic
reviews or meta-analysis were excluded.
The STROBE checklist was devised to determine the quality of reporting of
observational studies in all issues of 2014 in JCP. Each article was systematically
analyzed to evaluate whether the items named in the checklist are present or absent.
Outcome measurements were extracted and descriptive statistics used to present data of
STROBE compliance.

RESULTS
A total of 137 articles were published in the year of 2014 and following the title and
abstract screening 73 titles were excluded. The remaining 64 articles were then fully
analyzed by the primary reviewer. Following the full text screening, 13 additional articles
were excluded that did not meet the inclusion criteria. Total of 51 articles were included
for the final analysis. The majority of the included observational studies were cross-
sectional, 25 articles (49%). The remaining articles included 14 cohort studies (27%) and
12 case-control studies (24%).
The reporting quality of the three observational study designs were mixed.
3
Generally, none of the articles has fully adhered to the STROBE guidelines. The average
compliance for all the articles was 68.9%. The highest percentage of compliance was
found to be 84.3%, while the lowest value was calculated at 43.3%. We have also found
that the majority of the reviewed papers were 70-80% compliant to the STROBE
checklist. While the minority were either in the <50% adherence group (2 of 51 papers)
or >80% papers category (4 of 51 papers).

CONCLUSION

Within the limitations of this study, we concluded that the quality of reporting of
observational studies in JCP of 2014 is suboptimal. The weakest points in particular were
found to be: describing study design, statistical methods and reporting on participants
with missing data.
Adherence to the STROBE criteria must be reinforced to improve completeness
and transparency of reports of observational studies in clinical periodontology and
implant dentistry.

4
CHAPTER 1: INTRODUCTION & BACKGROUND

There has been an increasing demand over the past decades for evidence-based
periodontology to support decision-making and articulate the best available research with
clinical practice. Evidence based periodontology allows the clinician to implement the
best evidence available in the literature, in consultation with the patient, to come up with
the best treatment option for the patient
1
. Therefore, in order to practice evidence-based
periodontology, the clinician must be able to locate the relevant information in the
literature to the care of the patient and judge its quality. Only then s/he can think about
applying the findings in clinical practice. The challenge is to consciously distinguish
between the different levels of evidence and to determine the validity of the study design.
The hierarchy of evidence can range from the weakest evidence provided by in vitro
studies to the strongest form of evidence from randomized clinical trials and systematic
reviews
2
. The ultimate choice of an appropriate study design is not only dependent on the
research question or the disease of interest, but also on the resources available and ethical
consideration.
3

In clinical research, epidemiological studies can be divided into experimental
(interventional) studies or observational (non-interventional) studies (Fig.1). In
experimental studies, the investigators introduce some form of treatment or intervention
according to the research plan and evaluate its effect on the participants. The intervention
may involve a drug or a device; a procedure; or changes to the participants’ behavior in
an attempt to change disease progression and hence the treatment outcome.
3
Once a
participant has been formally entered into an interventional clinical trial, s/he is allocated
5
to a treatment group or a control group. The investigator will assign the participant into
either treatment or control group randomly or in a non-random manner. Therefore,
experimental studies have been subcategorized based on randomization into randomized
controlled trials (RCTs) or non-randomized controlled trials. The aim of randomization is
eliminate selection or allocation bias and to promote selection similarities between the
treatment or control groups in terms of baseline characteristics at entry of the clinical
trial. This will consequently reduce the chance of confounding and maximize the
efficiency of the trial. Due to this superior methodology, a RCT is considered the “gold-
standard” as it is the most reliable study design and has a high impact when practicing
evidence based periodontology.
4
However, conducting RCTs can be very expensive and
time consuming. In addition, the external validity (generalizability) of the study may be
limited by the characteristics of the studied population, procedures implemented or the
measured outcome.
5
More importantly, conducting an interventional study may be
impractical or restricted by ethical consideration. Therefore, observational studies maybe
considered as alternative source of evidence.
6

Observational Studies are carried out without any type of intervention and the
investigator simply observes and measures the disease among the participants and reports
the final outcome. Unlike experimental clinical trials, observational studies provide
poorer information as it is impossible to control for all factors that may affect the
outcome throughout the trial.
7
When designing an observational (non-interventional)
study, the investigator may conduct the study without a comparison group or assigns
participants to a comparison or control group to assess an association between a factor of
interest and the outcome. Therefore, observational studies are subcategorized into
6
descriptive or analytical observational studies.
8

Fig. 1 Classification of common clinical research designs
Descriptive observational studies often describe the characteristics of treatments and
outcomes in selected individuals. They also document an observation of a rare finding
and therefore, help generate awareness of new disease entities and spark new hypotheses
for further research. They are more convenient and inexpensive study design but
considered to be the lowest level of evidence when compared to other observational
studies. Descriptive studies can be presented in a form of a case report or chronicle of
multiple patients in case series with no control group involved.
6
For example, Ruggiero et
al,
9
presented a case series of 63 patients taking bisphosphonate medications who
developed oral lesions, characterized by non-healing extraction sockets and necrotic
Is there an active intervention?
Yes No
Experimental Study Observational Study
Randomization?
Yes No
Randomized
controlled
Trial
Non-
Randomized
controlled
Trial
Is there a comparison/
control group?
Yes No
Analytical
Study
Descriptive
Study
Case report/
series
Cohort
Study
Cross-sectional
Study
Case-control
Study
7
exposed bone. Although no definitive conclusions can be drawn from such report, it still
serve as a preliminary study to further investigate the prevalence, risk factors, prevention
and therapy of osteonecrosis.
Analytical observational studies, on the other hand, characterize an association
between predictors or exposures and outcomes in a population and analyze them for
possible cause and effect. Analytical studies are further divided into three main categories
based on methodology, the time frame that the study was conducted and measurements
taken. These categories include: cohort studies, cross-sectional studies and case control
studies
10
.
Cohort studies are considered to have the highest level of evidence when compared
to other methods of observational studies. A cohort study takes a group of participants
and usually follows them for a long period of time. The purpose of this study design is to
examine whether exposure to a particular etiological factor will affect the incidence of a
disease outcome in the future. First, the investigators assign a group of subjects that are a
subset of the general population and have the potential to develop the outcome of interest.
Disease free individuals recruited to cohorts may then be exposed or not exposed to the
hypothesized factors that are likely to influence the occurrence of the outcome
7
(Fig. 2).
Although most cohort studies are prospective, historical data can be analyzed and
information may be obtained retrospectively.
11

There are several important epidemiological measures that can be obtained from
cohort studies. Investigators can determine the relative risk, or the probability that an
exposed individual will develop a given disease when compared to non-exposed
individual
3
. In addition, they can determine incidence which is defined in the medical
8
dictionary as “the number of new cases of a specific disease occurring during a certain
period”
12

Fig. 2 Schematic diagram showing cohort study design

All cohort studies share the general weaknesses of observational study designs that
causal inference is challenging and the elucidation often influenced by confounding
variables. A particular drawback with prospective cohort studies is the difficulty in
maintaining consistency of measurements and outcomes over the long time scale. As the
follow-up time increases, participants may modify their behavior after initial enrollment
or may drop out over the course of the study leading to biased results
10
. Another problem
with cohort studies is that they are not ideal in studying rare diseases and a large sample
size is need. Therefore, they can be expensive to conduct and slow to yield any results
13
.
Unlike the long time frame nature of cohort studies, cross-sectional studies are a
snapshot of time and assess disease and exposure status of a population at one particular
time point. They are primarily conducted to determine the prevalence of a disease in a
given population, and one prototypical example is analytical survey
3
. The medical
9
dictionary defines prevalence as “ the number of cases of a disease in existence at certain
time point”
12
. Prevalence is important not only to clinicians but also to health planners
who want to know how many patients have certain diseases so that they can allocate
enough resources for their care.

The cross-sectional study design has important strengths and weaknesses. Generally,
they are inexpensive to conduct and can be completed in a relatively short period of time.
Another advantage is that they are ideal as the first step in a cohort study or a clinical trial
for prompting further research. However, one of the major drawbacks in cross sectional
studies is differentiating between cause and effect from simple association. Because we
do not know when the events occurred prior to initiating the study, we can only assess
association between the factor of interest and the disease and causality cannot be
determined. In addition, this type of study design is considered to have the highest risk of
bias when compared to cohort or case-control studies.
7

Case-control studies are frequently retrospective and are considered the next level of
evidence in observational studies. The investigator begins by choosing one group of
individuals with the disease (cases) and another group of individuals without the disease
(control). Once the investigator assign the groups, s/he then compares the level of
predictor variables in the two groups to see which predictors are associated with the
outcome/disease (Fig. 3). Case control studies provide information on the characteristics
of the cases and, more importantly, aim to determine the strength of association between
each predictor variable and the outcome. Because case-control studies work backwards,
10
investigators cannot calculate incidence rates or relative risks. Instead they do provide
estimates or approximate to the relative risk known as an odd ratio.
14

Case control studies, like the aforementioned observational studies, have their merits
and weaknesses. One of the major strengths of case control studies is that they are
relatively quick, cheap and easy to perform. They are particularly the ideal design for
researching uncommon conditions or when long latent periods exist between exposure
and disease. Therefore, this type of study is useful for generating hypotheses that can then
be tested using other study designs. However, case-control studies may be limited by the
potential of confounding variables and bias. Susceptibility to bias may take two major
forms. Sampling bias, in which the sample of patients with the disease (cases) may not be
a representative of all patients who develop the disease. In order to overcome this issue,
ideally cases enrolled in the study must be randomly selected from the population. This
may not only be difficult, but sometimes impossible because investigators may not be
able to identify patients who are undiagnosed or misdiagnosed. Another form of bias is
recall bias: when cases have differential ability to remember certain details about their
histories. Therefore, when assessing the predictor variables retrospectively there is a great
potential for measurement bias by the investigator.
3,7,14

Fig. 3 Schematic diagram showing case-control study design
11
As of today, the majority of the evidence to support clinical periodontal practice
and implant dentistry is derived from observational studies. Moreover, there is an
increasing demand to publish more observational studies in the periodontal literature and
that resulted in more quantity rather than quality research. In the medical literature, it was
reported that many observational studies failed to provide proper information with
impaired quality. Suboptimal reporting of a research paper may obstruct the assessment
of the strengths and weakness of the study and that leads to assumptions and uncertainty
by the reader
15
. It also limits the use of the data for secondary analysis or compromise
the ability to reproduce others’ finding.
16
Additionally, It is important to note that it is
the responsibility of the researchers to give a faithful presentation of the results of their
research in the public forum.
17

The need for transparent reporting of scientific research in general led to
influential statements and the development of guidelines to direct researchers and
improve the quality of reporting studies. For example in 1996, the Consolidated
Standards for Reporting Trials (CONSORT) for reporting RCTs was published and
revised 5 years later
18
. Many medical journals adopted this statement, which has helped
to improve the quality of reporting RCTs.
19
More recently, a network of researchers,
epidemiologist and journal editors developed a similar recommendation for the reporting
of observational research: Strengthening the Reporting of Observational Studies in
Epidemiology (STROBE)
20
. The statement aims to provide guidance to authors on how
to properly report observational research. This facilitates critical appraisal and
interpretation of the research by readers, reviewers and journal editors
20,21
. As mentioned
earlier, observational research makes use of many different study designs, and STROBE
12
statement focuses on the three analytical observational study designs: cohort, cross
sectional and case-control studies.
The format of STROBE statement is similar to CONSORT. It is a checklist of 22
items, which relate to the title, abstract, introduction, methods, results and discussion
sections of articles. The STROBE checklist is presented in a combined format for the
three study designs; however, separate checklists are available for each study design. Out
of the 22 items in the checklist, eighteen are common to all three designs while the other
four (items 6, 12, 14 and 15) are more design – specific. Some of the items require the
authors to provide additional information separately, for example, information about
cases and controls in case-control studies. The STROBE statement was published in
conjunction with a document that explains and elaborates on each item in the checklist to
guide the authors on how to improve their reporting
21
. Moreover, the first extension of
the STROBE statement for Genetic Association studies (STREGA) was published in
2009
22
. More recently, another extension of the STROBE statement was published to
advance the quality of reporting of Molecular Epidemiology for Infectious Diseases
(STROBE-ME).
23

It is important to emphasize that the STROBE statement was developed with the
intention to elaborate on how to report research well and not how research should be
done. Therefore, it is important to distinguish between the quality of reporting and the
quality of how the study was conducted and data analyzed.
21
When the study is well
documented and reported, it ensures that the conveyed information to the reader is
reliable. However, it does not necessarily means that the conducted research reflect a low
13
susceptibility to bias.
24
Nevertheless, when authors adhere to the STROBE guidelines,
issues such as confounding, bias and external validity could become more transparent.
Interpretation of data from observational studies in the periodontal literature is
often limited by suboptimal quality of reporting. Since the development of STROBE
statement, there have been attempts to improve the quality of reporting of observational
studies published in periodontal journals. However, it is still not clear which items from
the checklist are well reported and which items requires further attention.
The aim of our study was to conduct a cross-sectional survey on the quality of
reporting of published analytical observational studies in one of the major journals in
periodontology using a modified checklist of the STROBE statement. The most recent
issues published in a journal with the highest impact factor (IF) in periodontology and
implant dentistry, Journal of Clinical Periodontology (JCP), were evaluated. The focused
question was: what is the quality of reporting of observational studies in periodontology
and implant dentistry in JCP of 2014?

14
CHAPTER 2: MATERIALS & METHODS

Search Strategy

The initial structured search was conducted in MEDLINE electronic database. It
was decided to assess the quality of reporting of analytical observational studies
published in the most recent year of JCP at the time of conducting this study. To further
narrow down the selection for the journal, we selected one journal with high impact
factor in the field of periodontology and implant dentistry. Therefore, the search included
all observational studies that were published in the Journal of Clinical Periodontology
(JCP) during the period from Jan 1
st
, 2014 to Dec 31
st
, 2014.
• The combination of MeSH (Medical Subject Heading) terms were used and
included a combination of the journal title and the following terms:
o “Cohort ”OR “Prospective” OR “Retrospective” AND “Journal of clinical
periodontology”. Resulted in 55 articles
o “Observational study” AND “Journal of clinical periodontology”.
Resulted in 3 articles
o “Case control study” AND “Journal of clinical periodontology”. Resulted
in 10 articles.
o Cross sectional study AND Journal of clinical periodontology. Resulted 9
articles.
• Search limitations were the terms “English” and “humans” and the year 2014.
The total number of hits was 68. But the majority of the titles were repeated under
15
the different search terms that were used. In addition, when the search term
“Cohort ”OR “Prospective” OR “Retrospective” was used, the generated titles
included of a variety of studies including cohort studies, randomized controlled
trials and systematic reviews/meta-analysis.
• Therefore, it was concluded that indexing of articles using the MeSH terms was
too general to include specific study designs for this survey. It was decided to
carry out a hand search by screening the titles and abstracts of all issues of 2014
in JCP. Using the online journal’s web page, all issues were screened by the
primary reviewer (S.B).

Inclusion Criteria

Observational studies that corresponded to a relevant STROBE checklist item
were included for the analysis. Therefore, three main study designs of analytical
observational were included: case-control, cross sectional and cohort studies (Fig. 1).

Exclusion Criteria

Observational studies other than cohort, case-control, or cross-sectional studies such
as descriptive studies or surveys were excluded. Studies that are based on animal model
or cadavers or in vivo/in vitro studies were also excluded. In addition, systematic
reviews/ meta-analysis, case series/case reports or studies that are based on data collected
from previous RCT/experimental studies were all excluded.
16

To identify articles to be included for this review, keywords based on study design
were identified in either the title or the abstract. For example, titles were included for
further evaluation when the term “cross-sectional”, “cohort”, “retrospective”,
“prospective”, “observational”, or “case-control” was clearly stated in either the title or
the abstract. On the other hand, titles were excluded when the term “randomized
controlled trial”, “RCT”, “systematic review”, “meta-analysis”, “case report”, “case-
series”, “in vitro” or “in vivo” was identified in either the title or the abstract. When non
of the above terms or keywords can be identified in either the title or the abstract, the
materials and methods section of each selected article was further evaluated to identify its
study design. However, when the study design in the selected article was either missing
or not clearly stated using the common terminology, the article was assessed by a second
reviewer (S.K). Any disagreement was resolved by discussion between the reviewers and
when the two reviewers cannot agree on the study design then another opinion was
obtained from a third reviewer (H.M).

Data Extraction and Assessment of Quality of reporting

The reporting quality of observational studies designed as cohort, case-control and
cross sectional were scored using analytical and documentation criteria of the STROBE
statement. The checklist is composed of a total of 22 items that relate to different sections
in the article and six out of the 22 items contain more than one criterion: items 1, 6, 12,
13, 14, and 16. Therefore, articles were scored based on a total of 34 items to determine
17
if certain criteria were adequately reported. If the assessed paper failed one of the
criterion within one item, it will still be scored based on the other criteria under the same
item or category.

Some of the items within the STROBE checklist were subjective and required further
clarification in order to determine whether it is applicable or not. Therefore, the checklist
was modified using the explanatory article
21
that was published in conjunction with the
statement that elaborates on how to use the STROBE checklist. The objective of the
modified checklist was to eliminate subjectivity and provide a dichotomous scoring
system on the full 34 items of the STROBE checklist. Each statement in the checklist
was paraphrased into a series of questions that relate to each study design and can be
answered by “Yes”, “No” or “Not Applicable”. This will simplify the data extraction
process and also guarantees that data will be consistent across all the reviewed papers.

Using Microsoft Excel, a data sheet was generated and the collected data were then
converted to numerical scores; Yes - a score of 1 was given and NO - a score of zero was
recorded. All none applicable were stated as N/A and were then excluded from the
analysis. Outcome measurements were extracted and recorded by the same independent
reviewer (S.B). However, in cases where the primary reviewer was not sure if a particular
item was addressed in satisfactory manner then a second reviewer (S.K) was consulted.

18
Statistical Analysis

Descriptive statistics were used to assess the reporting characteristics of observational
studies published in JCP in the year of 2014. The number and proportion of items that
were adequately reported in a paper and those items that were not addressed properly
were analyzed for each study. The total number of scores for each article was calculated
and then divided by the total number of applicable items of the checklist to determine the
mean percentage of adherence per article to the STROBE checklist. Also the overall
range of compliance of all papers and the mean percentage of adherence per study design
was examined.

19
CHAPTER 3: RESULTS

Search Results

All titles and abstracts of articles in JCP were screened for analytical
observational studies in the issues of 2014. The flow diagram of the search strategy
(Fig.4) depicts the search process and the number of excluded articles. A total of 137
articles were published in the year of 2014 and following the title and abstract screening
73 titles were excluded. The remaining 64 articles were fully analyzed by the primary
reviewer. Some of the reviewed full text articles did not describe the study design and
that resulted in confusion and misinterpretation in terms of assigning a study design
description. Therefore, the materials and methods section of those articles were discussed
with another reviewer and any misinterpretation was resolved in a consensus discussion.
Out of the 64 articles reviewed, 13 additional articles were excluded, as they did not meet
the inclusion criteria. Total of 51
25-75
articles were included for the final analysis. The
excluded articles and the reason for exclusion are further detailed in Appendix D.

The included articles in this analysis, reported data on three different
observational study designs (Fig.5). The majority of the included observational studies
were cross-sectional, 25 articles (49%). The remaining articles included 14 cohort studies
(27%) and 12 case-control studies (24%).

20
Adherence of Articles to STROBE statement
The percentage of adherence to the STROBE checklist was calculated for each of
the 51 included articles (Fig.6). The figure clearly illustrates that none of the articles has
fully adhered to the STROBE guidelines. The mean compliance for all the articles was
68.9%. The highest percentage of compliance was found to be 84.3% (1 of 51 articles),
while the lowest value was calculated at 43.3% (2 of 51 articles). The range of adherence
of all the papers was also calculated and illustrated in (Fig. 7). We found that the majority
of the reviewed papers were 70-80% compliant to the STROBE checklist. While the
minority were either in the <50% (2 of 51 papers) adherence group or >80% (4 of 51
papers) category.
The mean percentage of adherence per article was also compared across the
different study designs (Fig. 8). For cohort studies, the mean percentage of adherence for
all the included 14 articles was 74.14%. For cross sectional and case-control studies the
mean percentage of adherence was 69.32% and 61.93 % respectively. In addition, the
mean percentage of adherence per STROBE checklist item was calculated for each study
design and it is illustrated in figures 9 – 15.

Items Properly Addressed
Results showed that all authors adhered fully to the following items with 100%
compliance rate (Fig. 16):
- Item #2: report the background/rational for their investigation
- Item #8: Data sources and measurements
- Item #15: Outcome data in the results section
21
- Item #16b: report of category boundaries
- Item #20: interpretation of the results in the discussion section
- Item #22: source of funding (JCP requires all authors to disclose all
sources of funding)

Items Not Addressed
The quality of reporting per item differed across all the included articles;
however, results showed that there are critical items that were generally poorly addressed
(Fig. 16). For example, the study design was indicated in the title or the abstract only in
39% of the articles. Other areas that were poorly described relate to the methodology
section of the STROBE checklist. For example, addressing bias (35%), sample size
calculations (29%), management of missing data (17.6%) and sensitivity analysis
(15.6%) in the statistical methods. In addition, other items that were infrequently
addressed relate to the results section of the STROBE checklist. More specifically,
information regarding reasons of non-participation was only reported in 33% of articles,
similarly, only 24% of the authors reported on the number of participants with missing
data.

22

23

24
Fig. 6 Percentage of Adherence of All Articles to the STROBE Checklist
43.30%
84.30%
43.30%
0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00%
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
% of Adherence to STROBE Checklist
Number of reviewed articles
25

Fig.7 Distribution of adherence of all papers to STROBE checklist

0
5
10
15
20
25
30
Number of Reviewed Papers
Range of compliance to STROBE
Distribution of Adherence to STROBE of All
Reviewed Papers
26

Fig. 8 Mean percentage of adherence of all papers based on different study designs

69.32%
74.14%
61.93%
% of Adherence to STROBE based on
Study Design
Cross Sectional studies
Cohort Studies
Case control studies
27

Fig. 9 Mean Percentage of adherence to STROBE checklist items 1, 2, and 3 per study
design

28

Fig. 10 Mean Percentage of adherence to STROBE checklist items 4, 5, 6, and 7 per
study design

29

Fig. 11 Mean Percentage of adherence to STROBE checklist items 8, 9, 10 and 11 per
study design

30

Fig. 12 Mean Percentage of adherence to STROBE checklist item 12 per study design

31

Fig. 13 Mean Percentage of adherence to STROBE checklist items 13 and 14 per study
design

32

Fig. 14 Mean Percentage of adherence to STROBE checklist items 15, 16 and 17 per
study design

33

Fig. 15 Mean Percentage of adherence to STROBE checklist items 18, 19, 20, 21 and 22
per study design

34
Fig. 16 Mean percentage of adherence of all papers per checklist item
39.20%
98%
100%
92.10%
56.80%
96.07%
94.10%
66.60%
68.60%
100%
35.20%
29.40%
98%
86.20%
90.10%
17.60%
51.40%
15.60%
56%
33.30%
23.50%
76.40%
24%
66.60%
100%
72.50%
100%
86.20%
49%
92%
62.70%
100%
72.50%
100%
1a
1b
2
3
4
5
6a
6b
7
8
9
10
11
12a
12b
12c
12d
12e
13a
13b
13c
14a
14b
14c
15
16a
16b
16c
17
18
19
20
21
22
35
CHAPTER 4: DISCUSSION

The purpose of this study was to conduct a cross-sectional survey of the quality of
reporting of analytical observational studies in 2014 issues of JCP utilizing the STROBE
checklist. The quality of reporting was calculated by determining the percentage of
adherence of each article to the total 34 items in the checklist. Results showed that none
of the 51 articles included in this analysis had fully adhered to the STROBE criteria. In
addition, this study has highlighted areas where reporting of observational studies is good
in periodontal literature, along with other areas where improvements are required.

Reporting Periodontal Observational Studies

The reporting quality of experimental studies in periodontology and implant
dentistry was the main focus for the past decades. Many systematic reviews were
published that measured quality of the reported information in RCTs
76-80
. However, not
until recently similar attention has been paid to non-experimental study designs. A
collaboration of specialist, epidemiologists and journal editors gathered to assess and
make specific recommendations to improve the quality of reporting of clinical research in
implant dentistry
81,82
. During the European Workshop on Periodontology (EWP)
82
discussions among the workshop participants were informed by systematic reviews on
the quality of reporting of observational studies: descriptive and analytical study designs.
The published systematic reviews covered different observational study designs including
the most frequently reported in the field such as case series
83
and also looked at case-
control and cohort studies
84
. In addition, they analyzed observational studies published in
36
different areas of clinical periodontology, for example, quality of reporting of research in
peri-implant diseases
85
.
Firstly, the systematic review by Meijer and Raghoebar
83
was conducted to
assess the quality of reporting of descriptive observational studies in implant dentistry.
The authors included only case series that were published in seven dental journals in the
time period of 1990 – 2010. The number of articles and abstracts screened in those
journals and in that particular time period resulted in 4657 titles but 260 papers were
reporting on descriptive studies and therefore included. More specifically, the authors
synthesized the data and evaluated the trend of adherence to the STROBE statement over
time comprise 20 years. They concluded that the quality of reporting of descriptive
studies is generally low; nevertheless, it has improved from 46% in 1990 to 70% in 2010.
The second systematic review
84
focused on the assessment of the quality of
reporting of risk factor studies in implant dentistry using the STROBE statement. . The
authors limited their search to specific risk factors associated with implant loss: smoking,
diabetes and periodontitis. Therefore, in order to evaluate risk factors in implant
dentistry, the authors only included specific analytical observational study designs: case-
control and cohort studies. They screened for relevant studies published from 2007 to the
May 2011 and included a total of 104 papers for their analysis. Out of the 104 papers,
only three papers were identified as cohort studies and none was a case-control study.
The remaining 101 papers were excluded from the analysis as they were either case series
or cross sectional studies. The authors found that the majority of the published risk factor
research in implant dentistry comprised of case series. Moreover, the quality of reporting
37
of the remaining three cohort studies was mostly poor and the statistical methods used
were found to be the weakest points.
The third systematic review that will be discussed was also published in 2012 as
part of the 8
th
European Workshop on Periodontology
85
. The authors aimed to review the
quality of reporting of the methodology of clinical research on incidence, prevalence and
risk factors of perio-implant diseases using the STROBE checklist. More specifically,
they included cross-sectional, case-control and prospective longitudinal studies reporting
on peri-implant diseases that were published until March 2011. From the 306 titles
identified, only 16 papers were eligible for further assessment and were included in the
review. The authors found that there were limitations in terms of adherence to the
STROBE statement. The quality of reporting of articles on the incidence, prevalence and
risk factors of peri-implant diseases was 67%, 65.3% and 63.8% respectively.
The aforementioned systematic reviews differed from our study in terms of the
objective, methodology and the total number of assessed articles. In our study, we
evaluated 51 analytical observational studies (cohort, cross-sectional and case-control)
that were published in JCP of 2014. We modified the STROBE checklist utilizing the
STROBE explanation and elaboration document
21
hoping to minimize subjectivity and
making it more dichotomous. In addition, we assessed each article based on each item
within the checklist and its subcategory. Therefore the calculated percentage of adherence
was based on the total of 34 items and not the main 22 items. This method allowed us to
determine more specifically which items were properly addressed from those that require
more improvement. Due to the lack of similarity between our study and the studies
reviewed above, we were not able to compare our results.
38
However, our study agrees with the findings from the previously published
systematic reviews
83-85
in the following:
• There are errors in indexing of case series and cohort studies using the electronic
search MEDLINE. Other studies have reported a similar problem in MEDLINE
for indexing systematic reviews and meta-analyses
86
. The inaccuracy of assigning
the publications based on study design appears to be related to the lack of
uniformity of terminology when assigning study designs. For example, there is a
considerable confusion between the definitions of descriptive observational
studies versus analytical observational studies. Some authors described their study
design as a cohort study when in fact it was case series
83
. Others failed to use the
correct term to describe a cohort study; instead they used alternative terms such as
retrospective or prospective study. Therefore, in our study, it seems justified to
use hand search for selecting the articles to overcome such issue and to eliminate
any selection bias.
• All the reviewed studies in the previous systematic reviews failed to adhere fully
to the STROBE statement. The mean percentage of compliance to STROBE
checklist for all the papers included in our review was 69%. A similar percentage
of 70% adherence was reported by Meijer and Raghoebar
83
when they evaluated
publications in 2010.
• There are certain items in the STROBE checklist that were not reported properly
in all the aforementioned systematic reviews and therefore, authors suggested
urgent need for improvement. We have found similar inconsistencies in the
quality of reporting of the these items which include and not limited to: proper
39
definition of study design, making efforts to address bias, explain how missing
data were addressed and reporting any sensitivity analysis.

Clinical and Research Implications

Thorough reporting is critical to maintain an undistorted scientific record, which
can be utilized for future research, clinical decision-making and health policy. In order to
understand the importance of optimal reporting of observational studies, we have to
emphasize on the implications of failing to do so on clinical practice and research.
Therefore the following significant areas of concern were identified based on the items of
the STROBE checklist and included:
• The reader should be able to identify the study design from the title or the
abstract. Therefore, it is critical for the authors to describe their study design
using the correct terminology that was referred to in the STROBE explanation and
elaboration document
21
. In our study, only 39% of the included papers fulfilled
this requirement.
• There are key points in the materials and methods section that specifically require
improvement. It is important for the authors to describe any efforts to assess bias.
It is striking that only 35% of the reviewed papers in this study were compliant
with that aspect. Failure to address possible biases produce results that differs
systematically from the truth and the validity becomes questionable. Another
issue is failure of reporting of sample size calculation. Sample size calculations
are important to detect what magnitude of effect the authors were looking for.
This means that a study should be large enough to obtain adequate statistical
40
power with sufficiently narrow confidence interval to answer a research question
21
. In our study, only 29% of the reviewed papers provided information about
study size calculations.
Another obvious shortcoming in the reviewed papers is failure to provide detailed
information on all statistical methods used. In our study, only 17% of authors
explained how missing data were handled and only 15 % described sensitivity
analysis. Poor reporting of these areas compromises the ability of the reader to
determine the strengths and weaknesses of the data provided. Also it is
challenging for the researcher to interpret the consistency of the information and
reproduce the study in future research
16
.
• Another priority area that requires attention and improvement in the quality of
reporting is the process of recruiting study participants. Authors should report in
details the number of participants at each stage of the study, including those who
refused to participate or failed to respond for follow up. This will minimize the risk
of selection bias and also enables the reader to judge whether the study population
was representative of the target population. Transparent information on the number
of participants with missing data is also critical to be documented as it is a
potential source of information bias
17
.

Strengths and Limitations of this Study

This study has systematically underscored critical areas requiring improvement in
the reporting of analytical observational studies in JCP. The STROBE checklist was
41
utilized with modification adopted from the STROBE document of explanation and
elaboration to help independent data extraction. It is important to note, however, that the
analysis was conducted by one independent reviewer (S.B) and, therefore, there might be
potential error in the collected data. Another limitation of this study is that it was mainly
based on observational studies published in one periodontal journal within one year.
Therefore, our results cannot be generalized to all other journals in the field of dentistry.

Recommendations for Future Research

It is important to highlight that STROBE statement was not developed as a tool to
assess the methodological quality of the published observational studies
87
. However, it
is recommended that editors from all dental journal embrace the STROBE statement to
improve the quality of reporting of observational research
81
.
With the emergence of biomarkers and molecular epidemiological research in the
field of periodontology, it would be interesting to implement the STROBE-ME extension
for future research. Also to assess whether the application of the extension results in a
different outcome in terms of the quality of reporting.

42
CHAPTER 5: CONCLUSION

Within the limitations of this study, the following can be concluded:
• The quality of reporting of observational studies in JCP of 2014 is suboptimal.
The weakest points in particular were found to be: describing study design,
statistical methods and reporting on participants with missing data.
• Adherence to the STROBE criteria must be reinforced to improve completeness
and transparency of reports of observational studies in clinical periodontology and
implant dentistry.
• Comprehensive reporting of study designs and methodology helps optimize
retrieval of the correct information by researchers and epidemiologist for future
research.

43
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Journal of Clinical Periodontology. 2013 Dec 12;41(2):113–20.
69. Lim SG, Han K, Kim H-A, Pyo SW, Cho Y-S, Kim K-S, et al.
Association between insulin resistance and periodontitis in Korean
adults. Journal of Clinical Periodontology. 2013 Dec 10;41(2):121–30.
70. Janket S-J, Baird AE, Jones JA, Jackson EA, Surakka M, Tao W, et al.
Number of teeth, C-reactive protein, fibrinogen and cardiovascular
mortality: a 15-year follow-up study in a Finnish cohort. Journal of
Clinical Periodontology. 2013 Dec 10;41(2):131–40.
71. Duarte PM, Bezerra JP, Miranda TS, Feres M, Chambrone L, Shaddox
LM. Local levels of inflammatory mediators in uncontrolled type 2
diabetic subjects with chronic periodontitis. Journal of Clinical
Periodontology. 2013 Nov 11;41(1):11–8.
72. Loozen G, Ozcelik O, Boon N, De Mol A, Schoen C, Quirynen M, et
al. Inter-bacterial correlations in subgingival biofilms: a large-scale
survey. Journal of Clinical Periodontology. 2013 Oct 16;41(1):1–10.
73. Eberhard J, Stiesch M, Kerling A, Bara C, Eulert C, Hilfiker-Kleiner
D, et al. Moderate and severe periodontitis are independent risk factors
associated with low cardiorespiratory fitness in sedentary non-smoking
men aged between 45 and 65 years. Journal of Clinical
Periodontology. 2013 Nov 13;41(1):31–7.
74. Porritt JM, Sufi F, Barlow A, Baker SR. The role of illness beliefs and
coping in the adjustment to dentine hypersensitivity. Journal of
Clinical Periodontology. 2013 Dec 12;41(1):60–9.
75. Kim J-H, Susin C, Min J-H, Suh H-Y, Sang E-J, Ku Y, et al.
Extraction sockets: erratic healing impeding factors. Journal of
Clinical Periodontology. 2013 Dec 12;41(1):80–5.

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77. Pjetursson BE, Zwahlen M, Lang NP. Quality of reporting of clinical
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54
Appendix A: STROBE 2007 (Original) checklist of items to be included in
reports of observational studies in epidemiology*
Checklist for cohort, case-control, and cross-sectional studies (combined)

Section/Topic
Item No Recommendation
(a) Indicate the study’s design with a commonly used term in the title or the
abstract
Title and abstract

1
(b) Provide in the abstract an informative and balanced summary of what was
done and what was found
Introduction
Background/rationale 2 Explain the scientific background and rationale for the investigation being
reported
Objectives 3 State specific objectives, including any pre-specified hypotheses
Methods
Study design 4 Present key elements of study design early in the paper
Setting 5 Describe the setting, locations, and relevant dates, including periods of
recruitment, exposure, follow-up, and data collection
(a) Cohort study—Give the eligibility criteria, and the sources and methods of
selection of participants. Describe methods of follow-up
Case-control study—Give the eligibility criteria, and the sources and methods
of case ascertainment and control selection. Give the rationale for the choice
of cases and controls
Cross-sectional study—Give the eligibility criteria, and the sources and
methods of selection of participants
Participants 6
(b) Cohort study—For matched studies, give matching criteria and number of
exposed and unexposed
Case-control study—For matched studies, give matching criteria and the
number of controls per case
Variables 7 Clearly define all outcomes, exposures, predictors, potential confounders, and
effect modifiers. Give diagnostic criteria, if applicable
Data sources/ measurement 8* For each variable of interest, give sources of data and details of methods of
assessment (measurement). Describe comparability of assessment methods if
there is more than one group
Bias 9 Describe any efforts to address potential sources of bias
Study size 10 Explain how the study size was arrived at
Quantitative variables 11 Explain how quantitative variables were handled in the analyses. If applicable,
describe which groupings were chosen and why
55
(a) Describe all statistical methods, including those used to control for
confounding
(b) Describe any methods used to examine subgroups and interactions
(c) Explain how missing data were addressed
d) Cohort study—If applicable, explain how loss to follow-up was addressed
Case-control study—If applicable, explain how matching of cases and
controls was addressed
Cross-sectional study—If applicable, describe analytical methods taking
account of sampling strategy
Statistical methods 12
(e) Describe any sensitivity analyses
Results
(a) Report numbers of individuals at each stage of study—eg numbers
potentially eligible, examined for eligibility, confirmed eligible, included in
the study, completing follow-up, and analysed
(b) Give reasons for non-participation at each stage
Participants 13*
(c) Consider use of a flow diagram
(a) Give characteristics of study participants (eg demographic, clinical, social)
and information on exposures and potential confounders
(b) Indicate number of participants with missing data for each variable of
interest
Descriptive data 14*
(c) Cohort study—Summarise follow-up time (eg, average and total amount)
Cohort study—Report numbers of outcome events or summary measures over
time
Case-control study—Report numbers in each exposure category, or summary
measures of exposure
Outcome data 15*
Cross-sectional study—Report numbers of outcome events or summary
measures
(a) Give unadjusted estimates and, if applicable, confounder-adjusted
estimates and their precision (eg, 95% confidence interval). Make clear which
confounders were adjusted for and why they were included
(b) Report category boundaries when continuous variables were categorized
Main results 16
(c) If relevant, consider translating estimates of relative risk into absolute risk
for a meaningful time period
Other analyses 17 Report other analyses done—eg analyses of subgroups and interactions, and
sensitivity analyses
Discussion
Key results 18 Summarise key results with reference to study objectives
Limitations 19 Discuss limitations of the study, taking into account sources of potential bias
or imprecision. Discuss both direction and magnitude of any potential bias
Interpretation 20 Give a cautious overall interpretation of results considering objectives,
limitations, multiplicity of analyses, results from similar studies, and other
relevant evidence
Generalisability 21 Discuss the generalisability (external validity) of the study results
Other information
56
Funding 22 Give the source of funding and the role of the funders for the present study
and, if applicable, for the original study on which the present article is based

*Give information separately for cases and controls in case-control studies and, if applicable, for exposed
and unexposed groups in cohort and cross-sectional studies.
Note: An Explanation and Elaboration article discusses each checklist item and gives methodological
background and published examples of transparent reporting. The STROBE checklist is best used in
conjunction with this article (freely available on the Web sites of PLoS Medicine at
http://www.plosmedicine.org/, Annals of Internal Medicine at http://www.annals.org/, and Epidemiology at
http://www.epidem.com/). Information on the STROBE Initiative is available at www.strobe-statement.org.

57

Appendix B: The Strengthening of Reporting of Observational Studies in Epidemiology (STROBE)
Modified checklist
For cohort, case-control, and cross-sectional studies (combined)

Section/Topic
Item # Recommendation Rules developed based on the Explanation Document
(a) Did the authors indicate the study’s design with a
commonly used term in the title or the abstract?
• If the study design was not specifically stated, then
this item will be scored = 0
• When incorrect terms are used to describe the study
design (ie, retrospective/prospective), this was
recorded as not being complete.
Title and abstract 1
(b) Does the abstract provide enough informative and
balanced summary of what was done and what was found?

Introduction
Background/rationale 2 Is the scientific background and rationale for the study
reported?

Objectives 3 Did the authors state specific objectives?
Are there any pre-specified hypotheses reported?

Methods
Study design 4 Are the key elements of study design reported early in the
paper?
• Presented early in the materials and methods section
or at the end of the introduction.
• Ill defining terms (“retrospective” or “prospective) to
describe cohort studies will be scored = 0
• Correct terminology to define study design: cohort;
cross-sectional; case-control.
Setting 5 Did the authors describe:
The settings?
Locations?
The relevant dates including periods of recruitment?
The relevant dates including periods of exposure?
The relevant dates including periods of follow-up?
• When the authors did not report the setting/location
but referred the reader to a previously published study
then the item scored = 1
• When the authors did not report the setting/location
and did not refer the reader to a previously published
study then the item scored = 0
58
The relevant dates including periods of data collection? • When the information is reported in the article but not
necessarily in the materials and methods section, the
item is rated as complete.

a) Cohort study— Did the authors describe:
• Eligibility criteria for participants?
• The sources and methods of selecting the participants?
• The methods of follow-up?

Case-control study—Did the authors describe:
• Eligibility criteria for participants?
• The sources and methods of case ascertainment and
control selection?
• The rationale for the choice of cases and controls?
Cross-sectional study—Did the authors describe:
• Eligibility criteria for participants?
• The sources and methods of selecting the participants?

Participants 6
For matched studies, did the authors describe
b) Cohort study—
Matching criteria and number of exposed and
unexposed?
Case-control study—
Matching criteria and the number of controls per case?

Variables 7 Did the authors clearly define all the following:
All outcomes, exposures, predictors, potential confounders,
and effect modifiers.
Did they report any diagnostic criteria, if applicable?
• Authors should clearly declare all the ‘candidate
variables” in the methods section and not selectively report
the ones included in the final analysis.
Data sources/
measurement
8* Did the authors describe sources of data and details of
methods of assessment (measurement) for each variable of
interest?
If there is more than one group, are the measurements
methods comparable?

Bias 9 Were there any efforts to address potential sources of bias? • Authors are recorded as having made attempts address
sources of bias if they reported any tools to do this;
standard deviation (SD) or validated scoring systems.
59
Study size 10 Did the authors explain how the study size was arrived at?
Quantitative variables 11 • Did the authors explain how quantitative variables
were handled in the analyses?
• If applicable:
o Did they describe which groupings were
chosen for quantitative variables?
o Did they describe why the quantitative
groups were chosen?

(a) Did they describe all statistical methods, including those
used to control for confounding?
• Unless the authors stated which confounders they
controlled for and why, this item was not recorded as
complete.
(b) Did they describe any methods used to examine
subgroups and interactions?

(c) Did they explain how missing data were addressed?

• Authors should report the number of missing values
for each variable of interest and, if possible, the
reason for missing values.
(d) Cohort study— Did they explain, if applicable, how loss
to follow-up was addressed?

Case-control study—Did they explain, if applicable, how
matching of cases and controls was addressed?

Cross-sectional study—Did they describe, if applicable, all
analytical methods taking account of sampling strategy?

Statistical methods 12
(e) Did the authors describe any sensitivity analyses?
Results
(a) Did they report the numbers of individuals at each stage
of study—e.g. numbers potentially eligible, examined for
eligibility, confirmed eligible, included in the study,
completing follow-up, and analyzed?
Participants 13*

(b) Did they give reasons for non-participation at each
stage?

60

(c) Did they use a flow diagram?
(a) Did they give the characteristics of study participants
(eg demographic, clinical, social) and information on
exposures and potential confounders?
• Authors should summarize continuous variables for
each group in the study by giving mean and standard
deviation.
• For asymmetrical distribution, the median and
percentile range should reported.
(b) Did they report the number of participants with missing
data for each variable of interest?

Descriptive data 14*
(c) Cohort study—Did they summarize follow-up time (eg,
average and total amount)?

Cohort study—Did they report the numbers of outcome
events or summary measures over time?

Case-control study—Did they report the numbers in each
exposure category, or summary measures of exposure?

Outcome data 15*
Cross-sectional study—Did they report the numbers of
outcome events or summary measures?

(a) Did the authors give unadjusted estimates and, if
applicable, confounder-adjusted estimates and their
precision (eg, 95% confidence interval)?

Did they clearly explain which confounders were
adjusted for and why they were included?

(b) Did they report category boundaries when continuous
variables were categorized?

Main results 16
(c) Did they, if relevant, consider translating estimates of
relative risk into absolute risk for a meaningful time period?
• Only relevant when there is was convincing evidence
of causal association
Other analyses 17 Did they report other analyses done—eg analyses of
subgroups and interactions, and sensitivity analyses?

Discussion
Key results 18 Did they provide a summary of the key results with
reference to study objectives?

61
Limitations 19 Did they discuss limitations of the study, taking into
account sources of potential bias or imprecision?

Did they discuss both direction and magnitude of any
potential bias?

Interpretation 20 Did they give a cautious overall interpretation of results
considering objectives, limitations, and multiplicity of
analyses, results from similar studies, and other relevant
evidence?

Generalisability 21 Did they discuss the generalisability (external validity) of
the study results?

Other information
Funding 22 Did they give the source of funding and the role of the
funders for the present study and, if applicable, for the
original study on which the present article is based?

*Give information separately for cases and controls in case-control studies and, if applicable, for exposed and unexposed groups in cohort and cross-sectional
studies.

62
Appendix C: Eligible Studies Included In The Analysis

Article Title Author Publication Study Design
Genome-wide exploration
identifies sex-specific genetic
effects of alleles upstream NPY
to increase the risk of severe
periodontitis in men
Sandra Freitag-Wolf,
Henrik Dommisch,
Christian Graetz
Dec-14 Case control study
A large candidate-gene
association study suggests
genetic variants at IRF5 and
PRDM1 to be associated with
aggressive periodontitis
Arne S. Schaefer,
Arne Jochens,
Henrik Dommisch
Dec-14 Case control study
Association between periodontal
condition and hypertension in a non-
smoking population aged
30–49 years: results of the
Health 2000 Survey in Finland
Emilia Ollikainen,
Tuomas Saxlin,
Tellervo Tervonen
Dec-14
Analytical Cross
sectional Survey
The association between
periodontal disease, tooth loss
and bone mineral density in a
Korean population
In-Hye Tak, Min-Ho
Shin
Dec-14 Cross sectional study
Effect of smoking cessation on
non-surgical periodontal therapy:
results after 24 months
Ecinele Francisca
Rosa, Priscila
Corraini
Dec-14
Prospective
experimental study
Microbial signature profiles of
periodontally healthy and
diseased patients
Talita Gomes Baeta
Lourenco et al.
Nov-14 Case control study
Periodontitis in coronary heart disease
patients: strong association between
bleeding on probing and systemic
biomarkers
Syed Akhtar H.
Bokhari1, Ayyaz A.
Khan
Nov-14 Cross sectional study
Periodontal findings in
individuals with newly identified pre-
diabetes or diabetes mellitus
Ira B. Lamster, Bin
Cheng
Nov-14 Cross sectional study
63
Levels of HIV-1 in subgingival biofilm of
HIV-infected patients
Priscila Pavan,
Viviane Tiago
Pereira, Rodrigo
Carvalho Souza
Nov-14 Cross sectional study
Estimates and multivariable risk
assessment of gingival recession in the
population of adults from Porto Alegre,
Brazil
Fernando S. Rios,
Ricardo S. A.
Costa
Nov-14 Cross sectional study
IgG sera levels against a subset of
periodonto-pathogens and
severity of disease in aggressive
periodontitis patients: a cross sectional
study of selected pocket sites
Luciana Saraiva,
Estela S. Rebeis
Oct-14 Cross sectional study
Changes in oral microflora after full-
mouth tooth extraction: a prospective
cohort study
Yvonne C.M. de
Waal, Edwin
G. Winkel
Oct-14
Prospective cohort
study
Supportive post-implant therapy: patient
compliance rates and impacting factors:
3-year follow-up
Eberhard Frisch, Dirk
Ziebolz
Oct-14
Retrospective Cohort
Study
Assessment of partial-mouth periodontal
examination protocols for periodontitis
surveillance
Duong T. Tran,
Isabel Gay, Xianglin
L. Du
Sep-14 Cross sectional study
Inter-rater agreement in the
diagnosis of mucositis and
peri-implantitis
Mauro Merli,
Francesco Bernardelli
Sep-14 Cross sectional study
Periodontal status and serum
biomarkers levels in
haemodialysis patients
Vandilson P.
Rodrigues, Silvana A.
Lib erio
Sep-14 Cross sectional study
Association between
periodontitis and preeclampsia in never-
smokers: a prospective study
Jung-Eun Ha, Jong-
Kwan Jun
Sep-14
Prospective cohort
study
Sense of coherence andincidence of
periodontal disease in adults
Jai Kanhai, Victoria
E. Harrison
Aug-14
Prospective cohort
survey
64
Quantitative gingival crevicular
fluid proteome in health and
periodontal disease using stable
isotope chemistries and mass
spectrometry
Leandro G. Carneiro,
Hesham
Nouh and Erdjan
Salih
Aug-14 Case control study
Volatile sulphur compound levels
and related factors in patients
with chronic renal failure
Ayse Gulsahi, S
ehrazat Evirgen
Aug-14 Case control study
Is gingival bleeding a symptom of
patients with type 1 von Willebrand
disease? A case– control study
Lisa Weickert,
Wolfgang Miesbach
Aug-14 Case control study
Relationship between increases in BMI
and changes in periodontal status: a
prospective cohort study
Daisuke Ekuni,
Shinsuke Mizutani
Aug-14
prospective cohort
study
Non-surgical and supportiveperiodontal
therapy: predictors of compliance
Chrysoula Delatola,
EvageliaAdonogianaki
Aug-14
Analytical Cross
sectional study
Periodontal pathogens and
associated factors in aggressive
periodontitis: results 5–17 years
after active periodontal therapy
Amelie Meyer-
B€aumer, Sigrun Eick
Jul-14 Cross sectional study
Periodontal infection, impaired fasting
glucose and impaired glucose tolerance:
results from the Continuous National
Health and Nutrition Examination
Survey 2009–2010
Nidhi Arora, Panos N.
Papapanou
Jul-14
Analytical Cross
sectional study
The periodontal health component of the
Renal Impairment In Secondary Care
(RIISC) cohort study: a description of the
rationale, methodology and initial
baseline results
Praveen Sharma,
Thomas Dietrich
Jul-14
Prospective cohort
study
Risk factors associated with the
longevity of multi-rooted teeth.
Long-term outcomes after active
and supportive periodontal therapy
Giovanni E. Salvi,
Daniel C. Mischler
Jul-14
Retrospective Cohort
Study
65
Involvement of the Wnt-bcatenin
signalling antagonists,sclerostin and
dickkopf-related protein 1, in chronic
periodontitis
Marcelo Henrique
Napimog, Cynthia
Nametala
Jun-14 Case control study
SLC23A1 polymorphism
rs6596473 in the vitamin C
transporter SVCT1 is associated
with aggressive periodontitis
Thijs M. H. de Jong,
Arne Jochens
Jun-14 Case control study
Applying quality assurance in
real time to compliant long-term
periodontal maintenance
patients utilizing costeffectiveness and
cost utility
Øystein Fardal and
Jostein Grytten
Jun-14 Case-control study
Salivary biomarkers of bacterial
burden, inflammatory response,
and tissue destruction in
periodontitis
Aino Salminen, Ulvi
K. Gursoy
May-14 Cross sectional study
The interaction between beta-3
adrenergic receptor polymorphism and
obesity to periodontal disease in
community-dwelling elderly Japanese
Akihiro Yoshihara,
Noriko Sugita
May-14
Cross sectional
study(survey)
Circulating undercarboxylated
osteocalcin and gingival
crevicular fluid tumour necrosis
factor-a in children
Khady Ka, Marie-
Claude
Rousseau
May-14 Cross sectional study
Compliance of cigarette smokers
with scheduled visits for supportive
periodontal therapy
Christoph A.
Ramseier, Salome
Kobrehe
May-14
Retrospective Cohort
Study
The prospective study of
autotransplanted severely impacted
developing premolars: periodontal status
and the long-term outcome
Paweł Plakwicz,
Ewa Monika
Czochrowska
May-14 Case control study
Assessment of tissue
oxygenation of periodontal
inflammation in smokers using
optical spectroscopy
Kan-Zhi Liu, Poliana
Mendes
Duarte
Apr-14 Cross sectional study
66
Matrix metalloproteinases and
myeloperoxidase in gingival
crevicular fluid provide sitespecific
diagnostic value for chronic periodontitis
Jussi M. Leppilahti,
Patricia A. Hern
andez-R
Apr-14 Cross sectional study
Role of cytokines in
development of pre-eclampsia
associated with periodontal
disease – Cohort Study
Ashok Kumar, Nargis
Be
Apr-14 Cohort study
Risk factors for the progression
of periodontal attachment loss: a 5-year
population-based study in South Brazil
Alex Nogueira Haas,
Marcius Comparsi
Wagner
Mar-14
Prospective cohort
study
Prediction of periodontal
disease: modelling and
validation in different general
German populations
Yiqiang Zhan, Birte
Holtfreter,
Mar-14
Analytical Cross
sectional study
Progression of attachment loss is strongly
associated with presence of the JP2
genotype of Aggregatibacter
actinomycetemcomitans: a prospective
cohort study of a young adolescent
population
Carola H€oglund
Aberg,
Francis Kwamin
Mar-14
Prospective cohort
study
Positive correlations between
hCAP18/LL-37 and chondroitin
sulphate levels in chronic
periodontitis
Anupong Makeudom,
Samakorn
Kulpawaropa
Mar-14 Cross sectional study
Relationship between
periodontal disease and
subclinical atherosclerosis: The
Dong-gu study
Young-Suk Jung,
Min-Ho Shin
Mar-14 Cross sectional study
Crevicular fluid biomarkers and
periodontal disease progression
Janet S. Kinney,
Thiago Morelli
Feb-14 Case control study
Association between insulin
resistance and periodontitis in
Korean adults
Sang Gyu Lim,
Kyungdo Han
Feb-14
Cross sectional
analytical Survey
67
Number of teeth, C-reactive
protein, fibrinogen and cardiovascular
mortality: a 15-year follow-up study in a
Finnish cohort
Sok-Ja Janket, Alison
E. Baird
Feb-14 Cohort study
Local levels of inflammatory
mediators in uncontrolled type 2
diabetic subjects with chronic
periodontitis
Poliana M. Duarte,
Joyce P.
Bezerra
Jan-14 Case control study
Inter-bacterial correlations insubgingival
biofilms: a large scale survey
Gitte Loozen, Onur
Ozcelik
Jan-14
Cross sectional
analytical Survey
Moderate and severe periodontitis are
independent risk factors associated with
low cardio-respiratory fitness in
sedentary non-smoking men
aged between 45 and 65 years
J€org Eberhard,
Meike Sti
Jan-14 Cross sectional study
The role of illness beliefs and
coping in the adjustment to
dentine hypersensitivity
Jenny M. Porritt1,
Farzana Sufi
Jan-14
Analytical Cohort
Survey
Extraction sockets: erratic
healing impeding factors
Jung-Hoon Kim,
Cristiano Susin
Jan-14 Retrospective cohort

68
Appendix D: List of Excluded Articles and Reason for Exclusion

Article Author Publication Reason for Exclusion
Distinct human T-lymphocyte responses
triggered by Porphyromonas gingivalis
capsular serotypes
Rolando Vernal,
Eva Diaz-Guerra,
Augusto Silva,
Mariano Sanz3 and
Jose A. Garcia-Sanz
Jan-14 In vitro Study
Role of 3D animation in periodontal
patient education: a randomized
controlled trial
Gertjan Cleeren,
Marc Quirynen,
Onur Ozcelik2 and
Wim Teughels
Jan-14 RCT
Derivation of a short form of the Dentine
Hypersensitivity Experience Questionnaire
Carolina Machuca,
Sarah R. Baker,
Farzana Sufi,
Stephen Mason,
Ashley Barlow and
Peter G. Robinson
Jan-14
Data based on previous RCT
Study
The Dentine Hypersensitivity Experience
Questionnaire: a longitudinal validation
study
Sarah R. Baker,
Barry J. Gibson,
Farzana Sufi,
Ashley Barlow and
Peter G. Robinson
Jan-14
Data based on 3- previous RCT
Study
Treatment of periodontitis improves the
atherosclerotic profile: a systematic
review and meta-analysis
Wijnand J. Teeuw,
Dagmar E. Slot,
Hendri Susanto,
Victor E. A Gerdes,
Frank Abbas,
Francesco D'Aiuto
Jan-14
Systematic review and meta-
analysis
Sinus augmentation using BMP-2 in a
bovine hydroxyapatite/collagen carrier in
dogs
Jae-Kook Cha,
Jung-Seok Lee,
Min-Soo Kim,
Seong-Ho Choi,
Kyoo-Sung Cho and
Ui-Won Jung
Jan-14 Animal Study: Dogs
Implant decontamination during surgical
peri-implantitis treatment: a randomized,
double-blind, placebo-controlled trial
Yvonne C. M. de
Waal, Gerry M.
Raghoebar, James
J. R. Huddleston
Slater
Jan-14 RCT
A challenge with Porphyromonas
gingivalis differentially affects the
osteoclastogenesis potential of
periodontal ligament fibroblasts
from periodontitis patients and
non-periodontitis donors
Dimitris Sokos, Nina
Scheres, Ton
Schoenmaker,
Vincent Everts and
Teun J. de Vries
Feb-14 In vitro Study
69
Differences in bacterial saliva
profile between periodontitis
patients and a control cohort
Daniel Belstrøm,
Nils-Erik Fiehn
Feb-14
The study design was case-
cohort (a merge of 2 study
designs) it does not follow the
conventional study design that
STROBE evaluate
Oral health education and therapy reduces
gingivitis during pregnancy
Maria L. Geisinger,
Nicolaas C. Geurs,
Jennifer L. Bain,
Maninder Kaur,
Philip J.
Vassilopoulos,
Suzanne P. Cliver,
John C. Hauth and
Michael S. Reddy
Feb-14 Experimental Study
Oral hygiene reinforcement in the
simplified periodontal treatment of 1 hour
Danae A. Apatzidou,
Penelope
Zygogianni,
Dimitra Sakellari
and Antonis
Konstantinidis
Feb-14 Experimental Study
One-stage full-mouth disinfection
combined with a periodontal dressing: a
randomized controlled clinical trial
Johan A. J. Keestra,
W im Coucke and
Marc Quirynen
Feb-14 RCT
A randomized controlled trial on
immediate surgery versus root planing in
patients with advanced periodontal
disease: a cost-effectiveness analysis
Seyed Reza
Miremadi,
Hugo De Bruyn,
Harold Steyaert,
Katrijn Princen,
Mehran M.
Sabzevar and
Jan Cosyn
Feb-14 RCT
Improving oral implant osseointegration
in a murine model via Wnt signal
amplification
Sylvain Mouraret,
Daniel J. Hunter,
Claire Bardet1,
Antoine Popelut,
John B. Brunski,
Catherine
Chaussain,
Philippe Bouchard
and Jill A. Helms
Feb-14 Animal Study: murine model
Bone healing with oxytocin-loaded
microporous β-TCP bone substitute in
ectopic bone formation model and critical-
sized osseous defect of rat
Jin-Woo Park1, Jae-
Min Kim, Heon-Jin
Lee, Seong-Hwa
Jeong, Jo-Young
Suh and Takao
Hanawa
Feb-14 Animal Study: Rat model
Meta-analysis of single crowns supported
by short (<10 mm) implants in the
posterior region
Luis André
Mezzomo, Rodrigo
Miller,Diego Triches,
Fernando Alonso
and Rosemary
Sadami A. Shinkai
Feb-14 Meta-analysis
70
Serotype-dependent response of human
dendritic cells stimulated with
Aggregatibacter actinomycetemcomitans
Jaime Díaz-Zúñiga,
Juan Pablo Yáñez,
Carla Alvarez,
Samanta Melgar-
Rodríguez, Marcela
Hernández,
Mariano Sanz and
Rolando Vernal,
Mar-14 In vitro Study
The accuracy of cone-beam computed
tomography in assessing maxillary molar
furcation involvement
Jing Qiao, Shiying
Wang, Jinyu Duan,
Yong Zhang, Yun
Qiu, Changzhou
Sun, and Denggao
Liu
Mar-14
CBCT USED - EXPERIMENTAL
COMPONENT
Evaluation of the effect of non-surgical
periodontal treatment on oral health-
related quality of life: estimation of
minimal important differences 1 year after
treatment
Birgitta Jönsson and
Kerstin Öhrn
Mar-14 DATA Based on RCT
Advanced tissue engineering scaffold
design for regeneration of the complex
hierarchical periodontal structure
Pedro F. Costa,
Cédryck Vaquette,
Qiyi Zhang, Rui L.
Reis, Saso
Ivanovski and
Dietmar W.
Hutmacher
Mar-14 In vitro Study
Clopidogrel enhances periodontal repair in
rats through decreased inflammation
Leila S. Coimbra,
Joao Paulo Steffens,
Carlos Rossa Jr,
Dana T. Graves and
Luis C. Spolidorio
Mar-14 Animal Study: Rat model
Clinical evaluation of coronally advanced
flap with or without acellular dermal
matrix graft on complete defect coverage
for the treatment of multiple gingival
recessions with thin tissue biotype
Cavid Ahmedbeyli,
Şebnem Dirikan
İpçi,
Gokser Cakar,
Bahar E. Kuru and
Selçuk Yılmaz
Mar-14 RCT
Minimally invasive transcrestal sinus floor
elevation with deproteinized bovine bone
or β-tricalcium phosphate: a multicenter,
double-blind, randomized, controlled
clinical trial
Leonardo Trombelli,
Giovanni
Franceschetti1,
Claudio Stacchi,
Luigi Minenna,
Orio Riccardi,
Rosario Di
Raimondo,
Alessandro Rizzi
and Roberto Farina
Mar-14 RCT
Non-invasive in vivo imaging by confocal
laser scanning microscopy of gingival
tissues following natural plaque
deposition
Jörg Eberhard,
Hendrik Loewen,
Alexander Krüger,
Sabine Donner,
Nico Stumpp,
Mandy Patzlaff,
Oliver Stachs,
Maria Reichard,
Tammo Ripken,
Meike Stiesch
Apr-14 In vivo Study
71
Long-term retrospective
evaluation of short implants in
the posterior areas: clinical
results after 10–12 years
Eduardo Anitua,
Laura Pinas
Apr-14 Retrospective case series
Comparative analysis of gingival tissue
antigen presentation pathways in ageing
and periodontitis
Octavio A.
Gonzalez, Michael J.
Novak, Sreenatha
Kirakodu, Luis
Orraca, Kuey-Chu
Chen, Arny
Stromberg,
Janis Gonzalez-
Martinez and
Jeffrey L. Ebersole
Apr-14 Animal Study: Monkey Model
Metronidazole alone or with amoxicillin as
adjuncts to non-surgical treatment of
chronic periodontitis: a secondary
analysis of microbiological results from a
randomized clinical trial
Geisla M. S. Soares,
Juliana A. V.
Mendes,
Maike P. Silva,
Marcelo Faveri,
Ricardo Teles,
Sigmund S.
Socransky,
Xiaoshan Wang,
Luciene C.
Figueiredo and
Magda Feres
Apr-14 RCT
Does enamel matrix derivative application
provide additional clinical benefits in
residual periodontal pockets associated
with suprabony defects? A systematic
review and meta-analysis of randomized
clinical trials
Filippo Graziani,
Stefano Gennai,
Silvia Cei,
Francesco Ducci,
Nicola Discepoli,
Alessandro
Carmignani and
Maurizio Tonett
Apr-14
Systematic review and meta-
analysis
Coronally advanced flap with and without
connective tissue graft for the treatment
of multiple gingival recessions: a
comparative short- and long-term
controlled randomized clinical trial
Giovanni Zucchelli,
Ilham
Mounssif,Claudio
Mazzotti, Martina
Stefanini,Matteo
Marzadori
,ElisabettaPetracci
and
LucioMontebugnoli
Apr-14 RCT
Coronally advanced flap versus the pouch
technique combined with a connective
tissue graft to treat Miller's class I
gingival recession: a randomized
controlled trial
Leila Salhi,
Geoffrey Lecloux,
Laurence Seidel,
Eric Rompen and
France Lambert
Apr-14 RCT
72
Outcomes of auto-transplanted teeth with
complete root formation: a systematic
review and meta-analysis
Wen-Chen Chung,
Yu-Kang T, Yi-Hung
Lin and Hsein-Kun
Lu
Apr-14
Systematic review and meta-
analysis
Sulcus fluid bone marker levels and the
outcome of surgical treatment of peri-
implantitis
Johan C. Wohlfahrt,
Anne M. Aass, Finn
Granfeldt ,Stale P.
Lyngstadaas
and Janne E.
Reseland
Apr-14 RCT
Activation of RANKL-induced osteoclasts
and memory T lymphocytes by
Porphyromonas gingivalis is serotype
dependant
Rolando Vernal,
Jaime Díaz-Zúñiga,
Samanta Melgar-
Rodríguez,
Myriam Pujol,
Eva Diaz-Guerra,
Augusto Silva,
Mariano Sanz and
Jose A. Garcia-Sanz
May-14 In vitro Study
Influence of intra-pocket anesthesia gel
on treatment outcome in periodontal
patients: a randomized controlled trial
Sonja H. M.
Derman, Claudia E.
Lowden, Martin
Hellmich and
Michael J. Noack
May-14 RCT
The effect of periodontal status and
occlusal support on masticatory
performance: the Suita study
Takayuki Kosaka,
Takahiro Ono,
Yoko Yoshimuta,
Momoyo Kida,
Miki Kikui,
Takashi Nokubi,
Yoshinobu Maeda
May-14 Experimental Study
Long-term analysis of osseointegrated
implants in non-smoker patients with a
previous history of periodontitis
Joerg Meyle,
Gero Gersok,
Rolf-Hasso
Boedeker and
José Roberto
Gonzales
May-14 Experimental Study
Experimental peri-implant mucositis at
different implant surfaces
Frank Schwarz,
Ilja Mihatovic,
Vladimir Golubovic,
Sigrun Eick,
Theresa Iglhaut and
Jürgen Becker
May-14 Experimental Study
73
Platform switch versus platform match in
the posterior mandible – 1-year results of
a multicentre randomized clinical trial
Fernando Guerra,
Wilfried Wagner,
Jörg Wiltfang,
Salomão Rocha,
Maximilian Moergel,
Eleonore Behrens
and Pedro Nicolau
May-14 RCT
Subgingival microbiota of
Sri Lankan tea labourers naïve
to oral hygiene measures
Long-Fei Zhuang,
Rory M. Watt
May-14 Descriptive Survey
The presence, function and regulation of
IL-17 and Th17 cells in periodontitis
Wan-Chien
Cheng,Francis J.
Hughes and Leonie
S. Taams
Jun-14 Review paper
Effects of periodontal treatment on lung
function and exacerbation frequency in
patients with chronic obstructive
pulmonary disease and chronic
periodontitis: A 2-year pilot randomized
controlled trial
Xuan Zhou, Jing
Han, ZhiqiangLiu,
Yiqing Song,
Zuomin Wangand
Zheng Sun
Jun-14 RCT
Efficacy of antimicrobial photodynamic
therapy in the management of chronic
periodontitis: a randomized controlled
clinical trial
Joseph Betsy,
Chandra S.
Prasanth,
Kamalasanan V.
Baiju, Janam
Prasanthila and
Narayanan Subhash
Jun-14 RCT
Tunnel technique with connective tissue
graft versus coronally advanced flap with
enamel matrix derivative for root
coverage: a RCT using 3D digital
measuring methods. Part I. Clinical and
patient-centred outcomes
Otto Zuhr, Stephan
F. Rebele, David
Schneider, Rony E.
Jung and Markus B.
Hürzeler
Jun-14 RCT
Tunnel technique with connective tissue
graft versus coronally advanced flap with
enamel matrix derivative for root
coverage: a RCT using 3D digital
measuring methods. Part II. Volumetric
studies on healing dynamics and gingival
dimensions
Otto Zuhr, Stephan
F. Rebele, David
Schneider, Rony E.
Jung and Markus B.
Hürzeler
Jun-14 RCT
Labial soft tissue volume evaluation of
different techniques for ridge preservation
after tooth extraction: a randomized
controlled clinical trial
David Schneider,
Patrick R.
Schmidlin,
Alexander Philipp,
Beat M. Annen,
Valerie Ronay,
Christoph H. F.
Hämmerle, Thomas
Attin and Ronald E.
Jung
Jun-14 RCT
Use of methodological tools for assessing
the quality of studies in periodontology
and implant dentistry: a systematic
review
Clovis M. Faggion
Jr, Fahd Huda and
Jason Wasiak
Jun-14 Systematic review
74
Oral health of patients under short
hospitalization period:
observational study
Lucas L. A. Sousa,
Wagner L. S. e.
Silva Filho
Jun-14 Observational Descriptive Study
Patient-reported outcome measures after
routine periodontal and implant surgical
procedures
Wah Ching Tan,
Gita Krishnaswamy
Jun-14 Observational clinical Audit
Comparison of periodontal conditions
among three elderly populations in Japan
and Germany
Toshinobu Hirotomi,
Thomas Kocher
Jul-14 Descriptive Survey
The effect of periodontal therapy on
glycaemic control in a Hispanic population
with type 2 diabetes: a randomized
controlled trial
Isabel C. Gay,
Duong T. Tran,
Adriana C.
Cavender, Robin
Weltman, Jennifer
Chang, Estelle
Luckenbach and
Gena D. Tribble
Jul-14 RCT
The effect of the thermal diode laser
(wavelength 808–980 nm) in non-surgical
periodontal therapy: a systematic review
and meta-analysis
Dagmar E. Slot,
Kirsten H.
Jorritsma, Charles
M. Cobb and Fridus
A. Van der Weijden
Jul-14
Systematic review and meta-
analysis
Surgical periodontal therapy with and
without initial scaling and root planing in
the management of chronic periodontitis:
a randomized clinical trial
Manar Aljateeli,
Tapan Koticha, Jill
Bashutski, James V.
Sugai, Thomas M.
Braun, William V.
Giannobile and
Hom-Lay Wang
Jul-14 RCT
Does the dimension of the graft influence
patient morbidity and root coverage
outcomes? A randomized controlled
clinical trial
Giovanni Zucchelli,
Ilham Mounssif,
Claudio Mazzotti,
Lucio Montebugnoli,
Matteo Sangiorgi,
Monica Mele and
Martina Stefanini
Jul-14 RCT
A randomized clinical trial comparing
guided implant surgery (bone- or mucosa-
supported) with mental navigation or the
use of a pilot-drill template
Marjolein
Vercruyssen,
Catherine Cox, Wim
Coucke, Ignace
Naert, Reinhilde
Jacobs and Marc
Quirynen
Jul-14 RCT
75
An RCT comparing patient-centred
outcome variables of guided surgery
(bone or mucosa supported) with
conventional implant placement
Marjolein
Vercruyssen,
Antoon De Laat,
Wim Coucke and
Marc Quirynen
Jul-14 RCT
TNF-α gene promoter polymorphisms
contribute to periodontitis susceptibility:
evidence from 46 studies
Cheng Ding,
Xiaowei Ji, Xing
Chen, Yan Xu and
Liangjun Zhong
Aug-14 Meta-analysis
Treatment of periodontal-endodontic
lesions – a systematic review
Julia C. Schmidt,
Clemens Walter,
Mauro Amato and
Roland Weiger
Aug-14 Systematic review
Growth/differentiation factor-5: pre-
clinical and clinical evaluations of
periodontal regeneration and alveolar
augmentation – review
Jaebum Lee and Ulf
M.E. Wikesjö
Aug-14 Review paper
Coronally advanced flap + connective
tissue graft techniques for the treatment
of deep gingival recession in the lower
incisors. A controlled randomized clinical
trial
Giovanni Zucchelli,
Matteo Marzadori,
Ilham Mounssif,
Claudio Mazzotti
and Martina
Stefanini
Aug-14 RCT
Mandibular reconstruction using a calcium
phosphate/polyethylene glycol hydrogel
carrier with BMP-2
Rudolf M. Gruber,
Sebastian Krohn,
Corinna Mauth,
Michel Dard, Aart
Molenberg,
Katharina Lange,
Christina Perske
and Henning
Schliephake
Aug-14
Experimental Study: animal
model (minipigs)
Effect of rhBMP-2 dose on bone
formation/maturation in a rat critical-size
calvarial defect model
Manuel Pelaez,
Cristiano Susin,
Jaebum Lee, Tiago
Fiorini, Frederick C.
Bisch, Douglas R.
Dixon, James C.
McPherson III,
Amanda N. Buxton
and Ulf M.E.
Wikesjö
Aug-14
Experimental Study: animal
model (rats)
Comparing clinical attachment level and
pocket depth for predicting periodontal
disease progression in healthy sites of
patients with chronic periodontitis using
multi-state Markov models
Ibrahimu Mdala,
Ingar Olsen, Anne
D. Haffajee,
Sigmund S.
Socransky, Magne
Thoresen and
Birgitte Freiesleben
de Blasio
Sep-14 Data based on clinical study
76
Cytokine gene expression profiles during
initiation, progression and resolution of
periodontitis
Jeffrey L. Ebersole,
Sreenatha
Kirakodu, Michael
John Novak, Arny J.
Stromberg, Shu
Shen, Luis Orraca,
Janis Gonzalez-
Martinez, Armando
Burgos and Octavio
A. Gonzale
Sep-14 Animal Study: Monkey Model
The effect of periodontal therapy on
cardiovascular risk markers: a 6-month
randomized clinical trial
André Luis Caúla,
Ronaldo Lira-Junior,
Eduardo Muniz
Barretto Tinoco and
Ricardo Guimarães
Fischer
Sep-14 RCT
Subgingival air-polishing with erythritol
during periodontal maintenance
Randomized clinical trial of twelve months
Nada Müller,
Raphaël Moëne,
José A. Cancela and
Andrea Mombelli
Sep-14 RCT
Metronidazole and amoxicillin as adjuncts
to scaling and root planing for the
treatment of type 2 diabetic subjects with
periodontitis: 1-year outcomes of a
randomized placebo-controlled clinical
trial
Tamires
Szeremeske
Miranda, Magda
Feres, Paula Juliana
Perez-Chaparro,
Marcelo Faveri,
Luciene Cristina
Figueiredo, Neila
Sumie Tamashiro,
Marta Ferreira
Bastos and Poliana
Mendes Duarte
Sep-14 RCT
Videoscope-assisted minimally invasive
periodontal surgery (V-MIS)
Stephen K. Harrel,
Celeste M.
Abraham
Sep-14 Case Report
Topographical relationship of the greater
palatine artery and the palatal spine.
Significance for periodontal surgery.
Sun-Kyoung Yu,
Myoung-Hwa Lee,
Byung Sun Park,
Yong Hyun Jeon,
Yoon Young Chung
and Heung-Joong
Kim
Sep-14 Cadaver study
Alterations of the bone dimension
following immediate implant placement
into extraction socket: systematic review
and meta-analysis
Chun-Teh Lee, Tzu-
Shan Chiu, Sung-
Kiang Chuang,
Dennis Tarnow and
Janet Stoupel
Sep-14
Systematic review and meta-
analysis
The molecular and cellular effects of
ageing on the periodontal ligament
Won Hee Lim, Bo
Liu, Su-Jung Mah,
Serafine Chen and
Jill A. Helms
Oct-14 Animal Study: mice model
77
Characteristics of periodontal biotype, its
dimensions, associations and prevalence:
a systematic review
Jeroen Zweers,
Renske Z. Thomas,
Dagmar E. Slot,
Arnold S. Weisgold
and Fridus G. A.
Van der Weijden
Oct-14 Systematic review
Effects of doxycycline on clinical,
microbiological and immunological
parameters in well-controlled diabetes
type-2 patients with periodontal disease:
a randomized, controlled clinical trial
Lazaros Tsalikis,
Dimitra Sakellari,
Panagiotis Dagalis,
Panagiota Boura
and Antonios
Konstantinidis
Oct-14 RCT
Bone formation in peri-implant defects
grafted with microparticles: a pilot animal
experimental study
Tobias Moest, Franz
Koehler,
Christopher Prechtl,
Christian Schmitt,
Georg Watzek and
Karl Andreas
Schlegel
Oct-14 Animal Experimental Study
Combination of LED light and platelet-
derived growth factor to accelerate
dentoalveolar osteogenesis
Po-Chun Chang,
Chen-Ying Wang
and Tsai Sheng-
Chueh
Oct-14 Animal Experimental Study
A systematic review and Bayesian
network meta-analysis of randomized
clinical trials on non-surgical treatments
for peri-implantitis
Clovis M. Faggion
Jr, Stefan Listl,
Nadine Frühauf,
Huei-Ju Chang and
Yu-Kang Tu
Oct-14
Systematic review and meta-
analysis
Smoking decreases structural and
functional resilience in the subgingival
ecosystem
Vinayak Joshi, Chad
Matthews, Marcelo
Aspiras, Marko de
Jager, Marilyn Ward
and Purnima Kumar
Nov-14 Experimental Study
Er:YAG laser versus scaling and root
planing as alternative or adjuvant for
chronic periodontitis treatment: a
systematic review
Yanhui Zhao,
Yuanzheng Yin, Li
Tao, Ping Nie,
Yanmei Tang and
Min Zhu
Nov-14 Systematic review
Impact of baseline microbiological status
on clinical outcomes in generalized
aggressive periodontitis patients treated
with or without adjunctive amoxicillin and
metronidazole: an exploratory analysis
from a randomized controlled clinical trial
Adrián Guerrero,
Luigi Nibali, Roberta
Lambertenghi,
Derren Ready, Jean
Suvan, Gareth S.
Griffiths, Michael
Wilson and Maurizio
S. Tonetti
Nov-14 RCT
Retaining or replacing molars with
furcation involvement: a cost-
effectiveness comparison of different
strategies
Falk Schwendicke,
Christian Graetz,
Michael Stolpe and
Christof Edmund
Dörfer
Nov-14
Descriptive observational study
(used simulated patient for
modelling)
78
Surgical treatment of peri-implantitis
using a bone substitute with or without a
resorbable membrane: a 5-year follow-up
Ann-Marie Roos-
Jansåker, Gösta
Rutger Persson,
Christel Lindahl and
Stefan Renvert
Nov-14
Data based on longitudinal single
blinded case series
Effect of smoking cessation on
non-surgical periodontal therapy:
results after 24 months
Ecinele Francisca
Rosa, Priscila
Corraini
14-Dec Experimental Study
Implant- and patient-centred outcomes of
guided surgery, a 1-year follow-up: An
RCT comparing guided surgery with
conventional implant placement
Marjolein
Vercruyssen,
Gerlinde van de
Wiele, Wim
Teughels, Ignace
Naert, Reinhilde
Jacobs and Marc
Quirynen
14-Dec RCT
A randomized trial on the aesthetic
outcomes of implant-supported
restorations with zirconia or titanium
abutments
na Carrillo de
Albornoz, Fabio
Vignoletti, Luca
Ferrantino, Eduardo
Cárdenas, Massimo
De Sanctis and
Mariano Sanz
14-Dec RCT
The potential for vertical bone
regeneration via maxillary periosteal
elevation
Sylvain Mouraret,
Ericka Von
Kaeppler, Claire
Bardet, Daniel J.
Hunter, Catherine
Chaussain, Philippe
Bouchard and Jill A.
Helms
14-Dec
Experimental Study: animal
model (mourine)
Incidence of peri-implant mucositis and
peri-implantitis in edentulous patients
with an implant-retained mandibular
overdenture during a 10-year follow-up
period
Henny J. A. Meijer,
Gerry M.
Raghoebar, Yvonne
C. M. de Waal and
Arjan Vissink
14-Dec Data based on clinical study
Quality of logistic regression reporting in
studies of tooth survival after periodontal
treatment
Clovis Mariano
Faggion Jr, Leandro
Chambrone and Yu-
Kang Tu
14-Dec Systematic review

Abstract (if available)

Abstract BACKGROUND: As of today, the majority of the evidence to support clinical periodontal practice and implant dentistry is derived from observational studies. However, interpretation of data from observational studies in the periodontal literature is often limited by suboptimal quality of reporting. The need for transparent reporting of scientific research in general led to influential statements and the development of guidelines to direct researchers and improve the quality of reporting studies. Since the development of STROBE statement in 2007, there have been attempts to improve the quality of reporting of observational studies published in periodontal journals. However, it is still not clear which items from the statement are well reported and which items requires further improvement. ❧ AIM: The aim of this study was to conduct a cross sectional survey on the quality of reporting on published analytical observational studies in one of the major journals in periodontology using a modified checklist of the STROBE statement. The most recent issues published in a journal with the highest impact factor (IF) in periodontology and implant dentistry, the Journal of Clinical Periodontology, were reviewed. The focused question was: what is the quality of reporting of observational studies in periodontology and implant dentistry in Journal of Clinical Periodontology? ❧ METHODS: An online search using MEDLINE followed by hand search of JCP was performed to identify observational studies published between January 01, 2014 and December 31, 2014. Inclusion criteria: analytical human observational studies (cohort, case-control and cross-sectional). All experimental studies or articles reporting on case series/reports, animal /cadaver studies, and in vitro studies were excluded. In addition, systematic reviews or meta-analysis were excluded. ❧ The STROBE checklist was devised to determine the quality of reporting of observational studies in all issues of 2014 in JCP. Each article was systematically analyzed to evaluate whether the items named in the checklist are present or absent. Outcome measurements were extracted and descriptive statistics used to present data of STROBE compliance. ❧ RESULTS: A total of 137 articles were published in the year of 2014 and following the title and abstract screening 73 titles were excluded. The remaining 64 articles were then fully analyzed by the primary reviewer. Following the full text screening, 13 additional articles were excluded that did not meet the inclusion criteria. Total of 51 articles were included for the final analysis. The majority of the included observational studies were cross-sectional, 25 articles (49%). The remaining articles included 14 cohort studies (27%) and 12 case-control studies (24%). The reporting quality of the three observational study designs were mixed. Generally, none of the articles has fully adhered to the STROBE guidelines. The average compliance for all the articles was 68.9%. The highest percentage of compliance was found to be 84.3%, while the lowest value was calculated at 43.3%. We have also found that the majority of the reviewed papers were 70-80% compliant to the STROBE checklist. While the minority were either in the <50% adherence group (2 of 51 papers) or >80% papers category (4 of 51 papers). ❧ CONCLUSION: Within the limitations of this study, we concluded that the quality of reporting of observational studies in JCP of 2014 is suboptimal. The weakest points in particular were found to be: describing study design, statistical methods and reporting on participants with missing data. Adherence to the STROBE criteria must be reinforced to improve completeness and transparency of reports of observational studies in clinical periodontology and implant dentistry.

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Asset Metadata

Creator Bushehri, Sarah (author)

Core Title Quality of reporting of observational studies in periodontology and implant dentistry: a cross-sectional survey

School School of Dentistry

Degree Master of Science

Degree Program Craniofacial Biology

Publication Date 07/30/2015

Defense Date 06/16/2015

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

Tag case-control,cohort,cross-sectional,OAI-PMH Harvest,observational studies,STROBE,survey

Format application/pdf (imt)

Language English

Contributor Electronically uploaded by the author (provenance)

Advisor Kar, Kian (committee chair), Paine, Michael L. (committee member), Sameshima, Glenn T. (committee member)

Creator Email bushehri@usc.edu,sarahbush@hotmail.com

Permanent Link (DOI) https://doi.org/10.25549/usctheses-c3-614570

Unique identifier UC11303871

Identifier etd-BushehriSa-3749.pdf (filename),usctheses-c3-614570 (legacy record id)

Legacy Identifier etd-BushehriSa-3749.pdf

Dmrecord 614570

Document Type Thesis

Format application/pdf (imt)

Rights Bushehri, Sarah

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 a...

Repository Name University of Southern California Digital Library

Repository Location USC Digital Library, University of Southern California, University Park Campus MC 2810, 3434 South Grand Avenue, 2nd Floor, Los Angeles, California 90089-2810, USA