Are sample sizes clear and justified in RCTs published in dental journals?

Is clustering accounted for in studies published in periodontology and oral implantology specialty journals?

BACKGROUND

Clustering effects can be encountered in periodontology and implant dentistry research. The aim of this study was to identify studies with clustering effects published in periodontology and oral implantology specialty journals and to assess the frequency by which clustered designs are correctly accounted for in the statistical analysis.

METHODS

Ten periodontology and oral implantology journals were searched to identify studies with clustering effects published between January 1, 2019 and July 31, 2021. Descriptive statistics and frequency distributions were calculated. Associations between the correct statistical handling of clustering effects and study characteristics were explored.

RESULTS

A total of 695 studies were included of which 45.0% correctly accounted for clustering effects in the statistical analysis. Certain journals (p < 0.01) and animal studies (p < 0.01) had lower odds of correctly accounting for clustering effects in the statistical analysis, whereas per unit increase in impact factor (p < 0.001), involvement of statistician (p < 0.001) and when the study design included either repeated measures only (p < 0.01) or both clustering and repeated measures (p < 0.001) had higher odds. The most commonly used tests were the mixed models or generalized estimating equations (64.2%).

CONCLUSIONS

Greater awareness of the importance of accounting for clustering effects is required to prevent incorrect inferences being drawn. Incorrect inferences are related to lack of data independence and the artificial inflation of the sample size which can result in statistically significant results which are not genuine. This issue can be further exaggerated in combination with publication bias.

Design and Methodological Issues of Within-Person (Split-Body) Randomized Controlled Trials Evaluating a Topical Treatment: A Systematic Review

BACKGROUND

Topical drugs are often used as first-line treatment for dermatological conditions. A within-person design may then be well adapted: it consists of randomizing lesions/body sites rather than patients, which are then concomitantly treated by the different drugs compared, reducing inter-group variability and therefore requiring fewer patients than the classical parallel-group trial.

OBJECTIVES

The aim of this review was to provide a methodological overview of within-person randomized trials (WP-RCTs) in dermatology.

METHODS

We searched for eligible trials published between 2017 and 2021 in MEDLINE, Embase, and Central in dermatology journals and the 6 highest-impact-factor general medical journals. Two authors selected publications and extracted data independently.

RESULTS

From 1,034 articles identified, we included 54 WP-RCTs, mainly for acne vulgaris, psoriasis, actinic keratosis, and atopic dermatitis. In most of the trials, patients had only 2 lesions/body sites. In none of the trials, did we detect a potential carry-across effect (known to be the major methodological problem in WP-RCTs). Twelve studies reported a care provider applying the treatment, and in 26 studies, the patients themselves applied the treatment. Finally, we also highlight statistical issues for the statistical analysis: overall, 14 (26.9%) studies used a test for independent observations, thus ignoring the between-lesion correlation.

CONCLUSION

Our systematic review highlights that despite the publication of the CONSORT checklist extension for WP-RCTs in 2017, this design is rarely used, and when it is, there are methodological and reporting concerns.

The reporting and methodological quality of split-mouth trials in oral implantology: A methodological study

OBJECTIVES

The objective of this study is to assess the reporting and methodological quality of split-mouth trials (SMTs) in oral implantology published during the past 10 years, and to investigate whether there was any improvement over time.

MATERIALS AND METHODS

We searched PubMed for SMTs in oral implantology published during 2011-20. We used CONSORT 2010, its extension for within-person trial (WPT), and an SMT-specific methodological checklist to assess trial reporting quality (TRQ), WPT-specific reporting quality (WRQ), and SMT-specific methodological quality (SMQ), respectively. Binary scores were given to each item, and total scores of TRQ (range 0-32), WRQ (0-15), and SMQ (0-3) were calculated for each study. Multivariable regression analyses were performed to compare the quality of SMTs published before (2011-17) and after (2018-20) the release of CONSORT for WPT.

RESULTS

Seventy-nine SMTs were included. The mean TRQ, WRQ, and SMQ were 16.4, 6.7, and 1.3, respectively. Less than one-third (n = 25, 31.6%) reported the rationale for using split-mouth designs. Only 4 (5.1%) trials adequately conducted sample size calculation, and 40 (50.6%) used appropriate statistical methods that considered dependency and clustering of data. In multivariable analyses, compared with 2011-17, studies published in 2018-20 had significantly higher TRQ (p = .044), while WRQ and SMQ did not show improvement.

CONCLUSIONS

The reporting and methodological quality of SMTs in oral implantology need to be improved. Joint efforts are needed to improve the reporting and methodology of SMTs in this field.

Characterizing the orthodontic research literature: 2020

OBJECTIVES

To characterize features of the current orthodontic literature.

METHODS AND MATERIALS

All research articles published in 2020 (N = 350) in the American Journal of Orthodontics and Dentofacial Orthopedics, The Angle Orthodontist, and the European Journal of Orthodontics were categorized on 48 features such as type of study (domain of generalization, subjects, and research design), analytical tools (statistical tests, power and normality of data, consistency of measurement, management of covariables, and corrections of multiple independent tests), and reporting characteristics. Consistency of the coding was high (κ > .990).

RESULTS

The "most typical" article was a cohort study reporting multiple patient outcomes at a single treatment location. Soundness of analyses was uneven, with about half providing information on power or normality of the data and consistency of measurement. Few articles addressed covariables or adjusted for multiple tests of independent outcomes. Photos and flow charts were commonly used to explain methods, and results were presented in multiple formats. There was a clear association between design and reporting characteristics and type of study for systematic reviews, meta-analyses, and case reports. There were small but consistent differences across the three journals.

CONCLUSIONS

The quality of the orthodontic research literature has advanced at an uneven pace, and this review identifies areas that could be strengthened. Substantial gaps remain in achieving accepted standards for randomized controlled trials and opportunities exist for better understanding measures of effect through design and analysis using regression techniques to identify sources of variance.

Publication bias in randomized controlled trials in dentistry. What factors affect statistical significance of outcomes?

OBJECTIVES

To record the proportion of Randomized Controlled Trials (RCTs) reporting significant (versus non- significant) primary outcomes, published across 12 high impact journals in Dentistry, covering 6 specialty domains. Associations with certain journal, publication and outcome characteristics were examined.

METHODS

We identified and included all RCTs published from January 1st, 2017 to December 31st, 2021 in the two journals with the highest impact factors (Clarivate Analytics, 2020) from each of the following domains: Periodontology, Endodontics, Restorative Dentistry/ Prosthodontics, Orthodontics, Paediatric Dentistry, Oral and Maxillofacial Surgery. The primary outcome was the proportion of significant/ non- significant findings reported for the primary outcomes under study, while a range of characteristics such as: journal, year of publication, impact factor, funding, registration and others, were tested for associations.

RESULTS

A total of 474 RCTs were identified and included, with the majority reporting statistically significant outcomes (321/474; 67.7%). The multivariable model revealed significant effects of predictors related to specialty domain (p = 0.01), continent (p = 0.003) and registration (p = 0.004). Compared to Periodontology, RCTs published in Endodontics (OR= 0.40; 95%CIs: 0.22, 0.76) and Orthodontics (OR= 0.41; 95%CIs: 0.23, 0.74) were less likely to present statistically significant effects. There was strong evidence that registered trials presented lower odds of reporting statistically significant findings (OR= 0.52; 95%CIs: 0.34, 0.81).

CONCLUSIONS

The entirety of dentistry domains demonstrated preferential publication practices of outcomes considered as "successful" and statistically significant, with domains such as Orthodontics and Endodontics being more balanced. Trial non- registration is still prevalent and associated with reporting of statistically significant effects.

CLINICAL SIGNIFICANCE

The findings of this empirical report bring attention to the interpretation of Systematic Reviews (SRs) conclusions. These largely depend on the availability and nature of outcomes of randomized controlled trials (RCTs) on a topic, which may impact on the synthesized estimate of a pooled effect and its direction.

Do sample size calculations in longitudinal orthodontic trials use the advantages of this study design?

OBJECTIVES

To examine whether optimal calculations of the sample size are being used in longitudinal orthodontic trials.

MATERIALS AND METHODS

Longitudinal orthodontic trials with a minimum of three time points of outcome assessment published between January 1, 2017, and December 30, 2020, were sourced from a single electronic database. Study characteristics at the level of each trial were undertaken independently and in duplicate. Descriptive statistics and summary values were calculated. Inferential statistics (Fisher's exact test and logistic regression) were applied to detect associations between reporting of a sample size calculation and the study characteristics.

RESULTS

A total of 147 trials were analyzed; 75.5% of these trials reported a sample size calculation with none reporting optimal sample size calculation for longitudinal trials. Most of the longitudinal orthodontic trials did not report the correlation and the number of longitudinal measurements in calculating the sample size. An association between reporting of a sample size calculation (yes or no) and the type of journal (orthodontic and non-orthodontic) was detected with higher odds of reporting a sample size calculation in orthodontic journals than in non-orthodontic journals (3.04; 95% confidence interval, 1.4-6.59; P < .01).

CONCLUSIONS

The findings of this study highlighted that the undertaking of optimal sample size calculations in longitudinal orthodontic trials is being underused. Greater awareness of the variables required for undertaking the correct sample size calculation in these trials is required to reduce suboptimal research practices.

Apriori sample size estimation and reporting in original articles published from 2012 to 2020 in two Asian orthodontic journals

AIMS:

To evaluate the proportion and completeness of reporting apriori sample size estimation (SSE) in research articles published in the Journal of Orthodontic Science (JOS) and the Journal of Indian Orthodontic Society (JIOS).

MATERIALS AND METHODS:

All online research articles published in both journals from 2012 to 2020 were screened. Those reporting apriori SSE were analyzed for the study design and completeness of SSE reporting (outcome parameter and assumptions, Type I error, Power/type II error, one or two-tailed test, the method used, justifications for assumptions, adjustments in sample size, and the target sample size). Chi-square or Fisher exact test was used to analyze the differences between the journals in the proportions of articles reporting these characteristics.

RESULTS:

Twenty articles (13.2%) in JOS and 24 (8.3%) in JIOS, have reported apriori SSE [χ² (1, N = 440) = 2.573, P=0.10]. Non-clinical and quasi-experimental studies formed nearly two-thirds of articles reporting SSE in JOS. Quasi-experimental (34%), randomized controlled trials (28%), and cross-sectional studies (24%) formed the bulk of articles reporting SSE in JIOS. Type II error/power was the most frequently reported characteristic in both (75% and 95.8% in JOS and JIOS, respectively), and the number of tails was the least (5% and 0%, respectively). More articles in JOS than JIOS reported the outcome variable used [65% vs. 12.5%, χ² (1, N = 44) = 12.99, P <.001] and provided justifications for the assumptions [70% vs 33.3%, χ² (1, N = 44) = 5.86, P = 0.01].

CONCLUSION:

The extent and completeness of reporting apriori SSE are suboptimal in these journals and require prompt and stringent curative measures.

The certainty of the evidence in oral health has not improved according to GRADE: a meta-epidemiological study

OBJECTIVE

The aim of this meta-epidemiological study was to provide an update of the certainty of the evidence in oral health by using the GRADE rating reported in oral health Cochrane systematic reviews (CSR).

STUDY DESIGN AND SETTING

All interventional oral health CSR published between 2003-2021 were sourced. Study characteristics were extracted at the level of the CSR and the outcome/meta-analysis. One-hundred-five CSR were eligible and analysed.

RESULTS

Almost a third of CSR (n=67) were excluded as a GRADE rating was not available. The most prevalent type of primary studies included in the CSR were randomized studies (93.4%) and the most used measure of effect was the risk ratio (67.3%). Overall, the certainty of the evidence according to the GRADE rating for all examined outcomes was very low/low (88%). The two most common reasons for downgrading the confidence in the evidence were study limitations (Risk of bias) and imprecision. The odds of moderate/high vs. low/very low-GRADE rating are higher for the primary compared to the secondary outcomes after adjusting for year and number of trials (OR 2.49; 95% CI: 1.09, 5.65; P=0.02). Per year (2010-2021 period) the odds of moderate/high vs. low/very low-GRADE rating decrease (OR 0.73; 95% CI: 0.60, 0.90; P=0.01), and as the number of trials per comparison increase the odds of moderate/high vs. low/very low GRADE rating increase (OR 1.13; 95% CI: 1.01, 1.25; P=0.001).

CONCLUSIONS

The certainty of the evidence in oral health when assessed with the GRADE rating remains predominantly low or very low.

Reporting of statistical sample size calculations in publications of trials on age-related macular degeneration, glaucoma and cataract

Background

Transparent and complete publications of randomised controlled trials (RCT) ought to comply with the guidelines of the CONSORT Statement, which stipulates sample size calculation as an important aspect of trial planning. The objective of this study was to analyse and compare the reporting of statistical sample size calculations in RCT papers on the treatment of age-related macular degeneration (AMD), glaucoma and cataract published in 2018.

Material and methods

This study comprises a total of 113 RCT papers (RCT-P) published in 2018 (AMD: 14, glaucoma: 28, cataract: 71), in English or German, and identified through an internet-based literature search in PubMed and EMBASE. The primary outcome measure of the study was the number of trials providing a complete description of the underlying sample case calculation on the basis of the variables required (significance level, expected outcomes, power, and resulting sample size).

Results

Of the RCTs reviewed, 64% (AMD), 61% (glaucoma) and 31% (cataract) provided a justification of the number of patients included. A complete description of the described studies’ sample size calculation including all the necessary values (primary outcome measure of this study) was described by 21% of the AMD, 29% of the cataract and 18% of the glaucoma RCT publications (in total: 24 of 113 (21%) at a confidence interval of 95%: [13%; 29%]).

Conclusion

All three treatment areas analysed lacked reporting quality regarding the justification of the number of patients included in a clinical trial based on a sample size calculation required for ethical reasons. More than half of all RCT publications reviewed did not provide all of the required information on statistical sample size calculation, and thus lacked transparency and completeness. It is therefore urgently required to involve methodologists in a study’s planning and publishing processes to ensure that methodology descriptions are transparent and of high quality.

Are treatment effect assumptions in orthodontic studies overoptimistic?

Background

At the clinical trial design stage, assumptions regarding the treatment effects to be detected should be appropriate so that the required sample size can be calculated. There is evidence in the medical literature that sample size assumption can be overoptimistic. The aim of this study was to compare the distribution of the assumed effects versus that of the observed effects as a proxy for overoptimistic treatment effect assumptions at the study design stage.

Materials and method

Systematic reviews (SRs) published between 1 January 2010 and 31 December 2019 containing at least one meta-analysis on continuous outcomes were identified electronically. SR and primary study level characteristics were extracted from the SRs and the individual trials. Details on the sample size calculation process and assumptions and the observed treatment effects were extracted.

Results

Eighty-five SRs with meta-analysis containing 347 primary trials were included. The median number of SR authors was 5 (interquartile range: 4–7). At the primary study level, the majority were single centre (78.1%), utilized a parallel design (52%), and rated as an unclear/moderate level of risk of bias (34.3%). A sample size was described in only 31.7% (110/347) of studies. From this cohort of 110 studies, in only 37 studies was the assumed clinical difference that the study was designed to detect reported (37/110). The assumed treatment effect was recalculated for the remaining 73 studies (73/110). The one-sided exact signed rank test showed a significant difference between the assumed and observed treatment effects (P < 0.001) suggesting greater values for the assumed effect sizes.

Conclusions

Careful consideration of the assumptions at the design stage of orthodontic studies are necessary in order to reduce the unreliability of clinical study results and research waste.

A priori power considerations in Endodontic Research. Do we miss the timeline?

AIM

To record the prevalence of a priori power calculations in manuscripts published in three endodontic journals between 2018 and 2020 and detect further associations with a number of study characteristics including journal, publication year, study design, geographic region, number of centres and authors, whether the primary outcome pertained to a statistically significant effect and whether confidence intervals (CIs) were reported.

METHODOLOGY

The contents of the three leading endodontic journals with the highest impact factor (International Endodontic Journal, IEJ; Journal of Endodontics, JOE; and Australian Endodontic Journal, AEJ) were assessed from January 2018 to December 2020. The proportion of articles reporting a priori power calculations were recorded, and relevant associations as described above were assessed. Univariable and multivariable logistic regression were used to identify significant predictors, whilst interaction and linear trend effects were also considered.

RESULTS

A total of 716 original research articles were included. The vast majority were published in the JOE (417/716; 58.2%), followed by the IEJ (225/716; 31.4%) and the AEJ (74/716; 10.4%). Overall, a priori power considerations were reported in 243 out of 716 articles (33.9%). The IEJ presented 1.61 times higher odds for including a priori power considerations compared to JOE (adjusted odds ratio, OR = 1.61; 95%CI: 1.11, 2.34), whilst for the AEJ, the corresponding odds were 41% lower in comparison to JOE (adjusted OR = 0.59; 95%CI: 0.31, 1.14). For each additional year indicating more recent publication, the odds for adopting appropriate reporting practices for power considerations were increased by 64% (adjusted OR = 1.64; 95%CIs: 1.32, 2.04). There was strong evidence that interventional research was associated with 10.54 times higher odds for a priori considerations compared to observational study design (adjusted OR = 10.54; 95%CIs: 5.50, 20.19).

CONCLUSIONS

The high prevalence of failure to include a priori power considerations was indicative of suboptimal reporting in endodontic research, in the three endodontic journals analysed. Although the condition improved over time, efforts to incorporate a correct determination of the required sample size at the design stage for any future study should be endorsed by journal editors, authors and the scientific community.

The 50 most-cited articles on clear aligner treatment: A bibliometric and visualized analysis

INTRODUCTION

Research on clear aligner treatment (CAT) has increased in recent years. In this study, we aimed to perform a bibliometric and visualized analysis to identify and critically assess the 50 most highly cited articles on CAT.

METHODS

Web of Science was selected as a data source and consulted until March 2020 to identify all articles potentially relevant to the analysis. All the eligible articles were collected until 50 manuscripts were listed. Article-based parameters, journal-based parameters, and author-based parameters were registered to perform the bibliometric analysis. Keywords were automatically harvested from the selected articles to implement the visualized analysis.

RESULTS

The search identified a total of 378 articles; the total number of citations of the selected articles varied from 15 to 112. The average number of citations per year varied from 1.15 to 13.83. The predominant study design was clinical (31.7%). Over the 15 journals in which the most cited articles were published, the American Journal of Orthodontics and Dentofacial Orthopedics published the majority of those included in the list (14) and also received the greatest number of citations (671). A total of 195 authors contributed to the 50 most cited articles; a significant portion of them (26) were unaffiliated with academic institutions. A total of 184 keywords were gathered from the article list.

CONCLUSIONS

The number of citations on CAT is expected to grow steadily in parallel with the rising number of research projects. The present work identifies the most influential articles on CAT and their characteristics, placing emphasis on the journals, the authors, and the topics addressed.

The reporting quality of split-mouth trials in orthodontics according to CONSORT guidelines: 2015-19

OBJECTIVES

To assess the reporting quality of split-mouth trials (SMTs) in orthodontic journals, and to identify factors associated with better reporting.

MATERIALS AND METHODS

Seven leading orthodontic journals were hand searched for SMTs published during 2015-19. The CONSORT 2010 guideline and CONSORT for within-person trial (WPT) extension were used to assess the trial reporting quality (TRQ) and WPT-specific reporting quality (WRQ) of included SMTs, respectively. A binary score (0 or 1) was given to each item of the guidelines, and total scores were calculated for TRQ (score range, 0-32) and WRQ (score range, 0-15). Univariable and multivariable linear regression analyses were performed to identify factors associated with TRQ and WRQ.

RESULTS

A total of 42 SMTs were included. The mean overall scores for TRQ and WRQ were 16.8 [standard deviation (SD) 7.1] and 5.6 (SD 2.3), respectively. Only 11 SMTs (26.2%) presented the rationale for using a split-mouth design. Key methodological items including random sequence generation (22/42, 52.4%), allocation concealment (9/42, 21.4%), and blinding (20/42, 47.6%) were poorly reported. Only six SMTs (14.3%) used a paired method for sample size calculation, and half (21/42, 50.0%) considered the dependent nature of data in statistical analysis. In multivariable analyses, higher TRQ and WRQ were both significantly associated with journal, reported use of CONSORT and funding status.

CONCLUSIONS

The reporting quality of SMTs in orthodontics has much room for improvement. Joint efforts from relevant stakeholders are needed to improve the reporting quality of SMTs and reduce relevant avoidable research waste.

A road map for designing and reporting clinical trials in paediatric dentistry

BACKGROUND

Unless clinical trials are well-designed, there is a risk that they will not be usable to improve patient care.

AIM

This paper discusses some factors important in designing clinical trials in paediatric dentistry. It uses the prevention and management of dental caries in children as the lens through which to look at these.

FINDINGS

Amongst the factors to consider are clear research questions and objectives; appropriate outcomes and outcome measures; sample size calculation and the level of randomisation; methods for random allocation; and operator/assessor training. Experts in trial design including statisticians and a trialist should be consulted early in the design process. The aspects of trial design unique to cariology trials such as 'clustering' of data items, mixed dentition issues and those related to trials involving children (communication, consent etc) should be considered. Comprehensive reporting of trial results is essential.

CONCLUSION

There are many readily available resources and tools to help the researcher design a trial of good quality that will yield results useful to the research community and beyond, to those who will implement the findings and ultimately those who will benefit from them.

Dental Research Waste in Design, Analysis, and Reporting: A Scoping Review

Research waste is highly prevalent across biomedical investigations. We aimed to assess the evidence on the extent of research waste in dental research. We performed a scoping review of empirical evaluations of dental studies assessing the prevalence and impact of limitations in design, conduct, analysis, and reporting of research. PubMed was searched using specific terms to retrieve studies dealing with design, conduct, analysis, and reporting of studies in dentistry, with no year or language restrictions. Of the 1,807 publications identified from the search and from manual searches, 71 were included in this review. The topic and article selection was based on the expert opinion of the authors. The existing evidence suggests that, although there are improvements over time, substantial deficiencies in all areas (design, conduct, analysis, reporting) were prevalent in dental research publications. Waste in research is a multifaceted problem without a simple solution. However, an appreciation of optimal research design and execution is a prerequisite and should be underpinned by policies that include appropriate training in research methods and properly aligned incentives.

Quality of Split-Mouth Trials in Dentistry: 1998, 2008, and 2018

The objectives of this study were to assess the reporting quality and methodological quality of split-mouth trials (SMTs) published during the past 2 decades and to determine whether there has been an improvement in their quality over time. We searched the MEDLINE database via PubMed to identify SMTs published in 1998, 2008, and 2018. For each included SMT, we used the CONsolidated Standards Of Reporting Trials (CONSORT) 2010 guideline, CONSORT for within-person trial (WPT) extension, and a new 3-item checklist to assess its trial reporting quality (TRQ), WPT-specific reporting quality (WRQ), and SMT-specific methodological quality (SMQ), respectively. Multivariable generalized linear models were performed to analyze the quality of SMTs over time, adjusting for potential confounding factors. A total of 119 SMTs were included. The mean overall score for the TRQ (score range, 0 to 32), WRQ (0 to 15), and SMQ (0 to 3) was 15.77 (SD 4.51), 6.06 (2.06), and 1.12 (0.70), respectively. The primary outcome was clearly defined in only 28 SMTs (23.5%), and only 27 (22.7%) presented a replicable sample size calculation. Only 45 SMTs (37.8%) provided the rationale for using a split-mouth design. The correlation between body sites was reported in only 5 studies (4.2%) for sample size calculation and 4 studies (3.4%) for statistical results. Only 2 studies (1.7%) performed an appropriate sample size calculation, and 46 (38.7%) chose appropriate statistical methods, both accounting for the correlation among treatment groups and the clustering/multiplicity of measurements within an individual. Results of regression analyses suggested that the TRQ of SMTs improved significantly with time ( P < 0.001), while there was no evidence of improvement in WRQ or SMQ. Both the reporting quality and methodological quality of SMTs still have much room for improvement. Concerted efforts are needed to improve the execution and reporting of SMTs.

[Influence of impact factor on reporting sample size calculations in publications on studies exemplified by AMD treatment : Cross-sectional investigation on the presence of sample size calculations in publications of RCTs on AMD treatment in journals with low and high impact factors]

BACKGROUND

For scientific and ethical reasons randomized controlled clinical trials (RCTs) should be based on a sample size calculation. The CONSORT statement, an established publication guideline for transparent study reporting, requires a sample size calculation in every study publication.

OBJECTIVE

The availability of sample size calculations in RCT publications on treatment of age-related macular degeneration (AMD) was investigated. The primary hypothesis of this investigation compared the prevalence of reported sample size calculations between journals with higher (≥5) versus lower (<5) impact factors (IF).

MATERIAL AND METHODS

It was examined whether information on sample size calculation was available in a series of 97 publications of RTCs on AMD treatment published between 2004 and 2014.

RESULTS

Only 46 out of 97 (47%) study publications provided information on the reason for the number of patients enrolled. The comparison of publications from journals with an IF ≥ 5 (63%, 30) and from journals with an IF < 5 (40%, 67) showed a statistically significant difference of 23% in the frequencies of available sample size calculations (95% confidence interval, CI 2%; 44%). Of the publications published before 2010, 43% reported a sample size calculation versus 51% of the publications afterwards.

CONCLUSION

Publications in journals with higher IF more frequently reported a sample size calculation. More than 50% of the publications did not report any sample size calculation. Authors and reviewers of publications should pay more attention to the explicit reporting of sample size calculations.

Validity of sample sizes in publications of randomised controlled trials on the treatment of age-related macular degeneration: cross-sectional evaluation

OBJECTIVE

The aim of this cross-sectional study was to examine the completeness and accuracy of the reporting of sample size calculations in randomised controlled trial (RCT) publications on the treatment of age-related macular degeneration (AMD).

METHODS

A sample of 97 RCTs published between 2004 and 2014 was reviewed for the calculation of their sample size. It was examined whether a (complete) description of the sample size calculation was presented. Furthermore, the sample size was recalculated, whenever possible based on the published details, in order to verify the reported number of patients.

PRIMARY OUTCOME MEASURE

The primary endpoint of this cross-sectional investigation was a described sample size calculation that was reproducible, complete and correct (maximum tolerated deviation between reported and replicated sample size ±2 participants per trial arm).

RESULTS

A total of 50 publications (52%) did not provide any information on the justification of the number of patients included. Only 17 publications (18%) provided all the necessary parameters for recalculation; 8 of 97 (8%, 95%-CI: 4% to 16%) publications achieved the primary endpoint. The median relative deviation between reported and recalculated sample sizes was 1%, with a range from -43% to +66%.

CONCLUSION

Although a transparent sample size legitimation is a crucial determinant of an RCT's methodological validity, more than half of the RCT publications considered failed to report them. Furthermore, reported sample size legitimations were often incomplete or incorrect. In summary, clinical authors should pay more attention to the transparent reporting of sample size calculation, and clinical journal reviewers may opt to reproduce reported sample size calculations.

SYNOPSIS

More than half of the analysed RCT publications on the treatment of AMD did not report a transparent sample size calculation. Only 8% reported a complete and correct sample size calculation.

A priori power considerations in orthodontic research: a 3 year meta-epidemiologic study

Aim

To assess the prevalence of a priori power calculations in orthodontic literature and to identify potential associations with a number of study characteristics, including journal, year of publication and statistical significance of the outcome.

Materials and methods

The electronic archives of four leading orthodontic journals with the highest impact factor (American Journal of Orthodontics and Dentofacial Orthopedics, AJODO; European Journal of Orthodontics, EJO; Angle Orthodontist, ANGLE; Orthodontics and Craniofacial Research, OCR) were assessed over a 3 year period until December 2018. The proportion of articles reporting a priori power calculations were recorded, and the association with journal, year of publication, study design, continent of authorship, number of centres and researchers, statistical significance of results and reporting of confidence intervals (CIs) was assessed. Univariable and multivariable regression were used to identify significant predictors.

Results

Overall, 654 eligible articles were retrieved, with the majority published in the AJODO (n = 246, 37.6%), followed by ANGLE (n = 222, 33.9%) and EJO (n = 139, 21.3%). A total of 233 studies (35.6%) presented power considerations a priori along with sample size calculations. Study design was a very strong predictor with interventional design presenting 3.02 times higher odds for a priori power assumptions compared to observational research [odds ratio (OR): 3.02; 95% CIs: 2.06, 4.42; P &lt; 0.001].

Conclusions

Presentation of a priori power considerations for sample size calculations was not universal in contemporary orthodontic literature, while specific study designs such as observational or animal and in vitro studies were less likely to report such considerations.

CONSORT 2010 statement: extension checklist for reporting within person randomised trials

Evidence shows that the quality of reporting of randomised controlled trials (RCTs) is not optimal. The lack of transparent reporting impedes readers from judging the reliability and validity of trial findings and researchers from extracting information for systematic reviews and results in research waste. The Consolidated Standards of Reporting Trials (CONSORT) statement was developed to improve the reporting of RCTs. Within person trials are used for conditions that can affect two or more body sites, and are a useful and efficient tool because the comparisons between interventions are within people. Such trials are most commonly conducted in ophthalmology, dentistry, and dermatology. The reporting of within person trials has, however, been variable and incomplete, hindering their use in clinical decision making and by future researchers. This document presents the CONSORT extension to within person trials. It aims to facilitate the reporting of these trials. It extends 16 items of the CONSORT 2010 checklist and introduces a modified flowchart and baseline table to enhance transparency. Examples of good reporting and evidence based rationale for CONSORT within person checklist items are provided.

Comparison of nuisance parameters in pediatric versus adult randomized trials: a meta-epidemiologic empirical evaluation

Background

We wished to compare the nuisance parameters of pediatric vs. adult randomized-trials (RCTs) and determine if the latter can be used in sample size computations of the former.

Methods

In this meta-epidemiologic empirical evaluation we examined meta-analyses from the Cochrane Database of Systematic-Reviews, with at least one pediatric-RCT and at least one adult-RCT. Within each meta-analysis of binary efficacy-outcomes, we calculated the pooled-control-group event-rate (CER) across separately all pediatric and adult-trials, using random-effect models and subsequently calculated the control-group event-rate risk-ratio (CER-RR) of the pooled-pediatric-CERs vs. adult-CERs. Within each meta-analysis with continuous outcomes we calculated the pooled-control-group effect standard deviation (CE-SD) across separately all pediatric and adult-trials and subsequently calculated the CE-SD-ratio of the pooled-pediatric-CE-SDs vs. adult-CE-SDs. We then calculated across all meta-analyses the pooled-CER-RRs and pooled-CE-SD-ratios (primary endpoints) and the pooled-magnitude of effect-sizes of CER-RRs and CE-SD-ratios using REMs. A ratio < 1 indicates that pediatric trials have smaller nuisance parameters than adult trials.

Results

We analyzed 208 meta-analyses (135 for binary-outcomes, 73 for continuous-outcomes). For binary outcomes, pediatric-RCTs had on average 10% smaller CERs than adult-RCTs (summary-CE-RR: 0.90; 95% CI: 0.83, 0.98). For mortality outcomes the summary-CE-RR was 0.48 (95% CIs: 0.31, 0.74). For continuous outcomes, pediatric-RCTs had on average 26% smaller CE-SDs than adult-RCTs (summary-CE-SD-ratio: 0.74).

Conclusions

Clinically relevant differences in nuisance parameters between pediatric and adult trials were detected. These differences have implications for design of future studies. Extrapolation of nuisance parameters for sample-sizes calculations from adult-trials to pediatric-trials should be cautiously done.

The Impact of a Customized Tray on In-Office Bleaching Tooth Sensitivity: A Randomized Clinical Trial

Objective

It was recently demonstrated that using a tray over a bleaching agent reduces its pulpal chamber penetration, which can reduce tooth sensitivity. This study evaluated the effect of the sealed technique on the presence and level of sensitivity reported by patients during and after the bleaching procedure performed in office.

Methods

Forty-six patients underwent a bleaching procedure with 35% hydrogen peroxide used in a single application of 45 minutes for two sessions with an interval of seven days. A customized tray was maintained over the bleaching agent during the entire procedure in half of the patients. The sensitivity level was evaluated during and immediately after the bleaching using verbal and visual analogue scales. The shade alteration was evaluated with a bleach guide scale. The peak sensitivity after 24 hours and the presence/level at 24 hours were also evaluated using a verbal rating scale. Relative risks were calculated for all time assessments. Data on the sensitivity level for both scales were subjected to Friedman and Mann-Whitney tests (α=0.05). Data on the shades were analyzed by two-way repeated-measures analysis of variance and Tukey's test (α=0.05).

Results

The use of a customized tray increased the relative risks to the tooth measured 24 hours after each bleaching session. The sealed technique also increased the level of tooth sensitivity only at 24 hours after the first session. No difference was observed between the bleaching techniques regarding the shade evaluation.

Conclusion

Using a tray over the bleaching agent can increase the level and risk of tooth sensitivity for the first 24 hours after in-office bleaching.

Risk of bias and magnitude of effect in orthodontic randomized controlled trials: a meta-epidemiological review

AIM

To assess the risk of bias (RoB) in a subset of randomized controlled trials (RCTs) published in orthodontic journals using the Cochrane RoB tool and to identify associations between domain RoB assessment and treatment effect estimates.

MATERIALS AND METHODS

Fifty consecutive issues of four major orthodontic journals were electronically searched to identify RCTs. The quality of the included studies was assessed using the Cochrane RoB tool, which involves seven domains rated as 'low', 'unclear' or 'high': random sequence generation, allocation concealment, blinding of participants and personnel, blinding of outcome assessment, incomplete outcome data, and selective outcome reporting, and other threats to internal validity. Estimates and confidence intervals (CIs) were recorded or calculated where possible for binary and continuous outcome measures. Meta-regression models were employed to assess the impact of RoB per domain on the magnitude of treatment effect.

RESULTS

One hundred and one eligible studies involving 128 pair-wise comparisons were retrieved. Blinding of outcome assessors and incomplete outcome data were frequently judged as 'high' for RoB both for studies with binary and continuous outcome (42.9 and 48.8 per cent, respectively). For binary outcomes, high RoB regarding random sequence generation [odds ratio (OR): 5.97, 95% CI: 2.03, 17.63, P-value: 0.002] and incomplete outcome data (OR: 4.07, 95% CI: 1.03, 16.15, P-value: 0.05) were more likely to provide exaggerated effect estimates.

CONCLUSIONS

There is a need for improved clinical trial methodology and reporting, in order to avoid inflated associations and erroneous conclusions.

The CONSORT Statement: Application within and adaptations for orthodontic trials

High-quality randomized controlled trials (RCTs) are an integral part of evidence-based medicine. RCTs are the bricks and mortar of high-quality systematic reviews, which are important determinants of health care policy and clinical practice. For published research to be used most effectively, investigators and authors should follow the guidelines for accurate and transparent reporting of RCTs. The consolidated standards of reporting trials (CONSORT) statement and its extensions are among the most widely used reporting guidelines in biomedical research. CONSORT was adopted by the American Journal of Orthodontics and Dentofacial Orthopedics in 2004. Since 2011, this Journal has been actively implementing compliance with the CONSORT reporting guidelines. The objective of this explanatory article is to highlight the relevance and implications of the various CONSORT items to help authors to achieve CONSORT compliance in their research submissions of RCTs to this and other orthodontic journals.

Outcome discrepancies and selective reporting: impacting the leading journals?

Background

Selective outcome reporting of either interesting or positive research findings is problematic, running the risk of poorly-informed treatment decisions. We aimed to assess the extent of outcome and other discrepancies and possible selective reporting between registry entries and published reports among leading medical journals.

Methods

Randomized controlled trials published over a 6-month period from July to December 31^st, 2013, were identified in five high impact medical journals: The Lancet, British Medical Journal, New England Journal of Medicine, Annals of Internal Medicine and Journal of American Medical Association were obtained. Discrepancies between published studies and registry entries were identified and related to factors including registration timing, source of funding and presence of statistically significant results.

Results

Over the 6-month period, 137 RCTs were found. Of these, 18% (n = 25) had discrepancies related to primary outcomes with the primary outcome changed in 15% (n = 20). Moreover, differences relating to non-primary outcomes were found in 64% (n = 87) with both omission of pre-specified non-primary outcomes (39%) and introduction of new non-primary outcomes (44%) common. No relationship between primary or non-primary outcome change and registration timing (prospective or retrospective; P = 0.11), source of funding (P = 0.92) and presence of statistically significant results (P = 0.92) was found.

Conclusions

Discrepancies between registry entries and published articles for primary and non-primary outcomes were common among trials published in leading medical journals. Novel approaches are required to address this problem.

Overview of registered studies in orthodontics: Evaluation of the ClinicalTrials.gov registry

INTRODUCTION

The Food and Drug Administration Modernization Act of 1997 made it mandatory for all phase II through IV trials regulated by this Act to be registered. After this, the National Institutes of Health created ClinicalTrials.gov, which is a registry of publicly and privately supported clinical studies of human participants. The objective of this study was to examine the characteristics of registered studies in orthodontics.

METHODS

The ClinicalTrials.gov Web site was used to query all registered orthodontic studies. The search term used was "orthodontics." No limitations were placed for the time period. All registered studies regardless of their recruitment status, study results, and study type were selected for analysis.

RESULTS

A total of 64 orthodontic studies were registered as of January 1, 2014. Of these, 52 were interventional, and 12 were observational. Close to 60% of the interventional studies and 66.7% of the observational studies had sample sizes of 50 or fewer subjects. About 21.2% of the interventional studies and 16.7% of the observational studies had sample sizes greater than 100. Only 1 study was funded by the National Institutes of Health, and the rest were funded by "other" or "industry" sources. Close to 87.7% of the interventional studies were randomized. Interventional model assignments included factorial assignment (3.9%), parallel assignments (74.5%), crossover assignment (7.8%), and single-group assignment (13.7%). Most studies were treatment oriented (80.4%). The types of masking used by the interventional studies included open label (28.9%), single blind (44.2%), and double blind (26.9%). Outcome assessors were blinded in only 6 studies.

CONCLUSIONS

Orthodontic studies registered in ClinicalTrials.gov are dominated by small single-center studies. There are wide variations with regard to treatment allocation approaches and randomization methods in the studies. These results also indicate the need for multicenter clinical studies in orthodontics.