Language bias in orthodontic systematic reviews: A meta-epidemiological study

BACKGROUND

Orthodontic systematic reviews (SRs) include studies published mostly in English than non-English languages. Including only English studies in SRs may result in a language bias. This meta-epidemiological study aimed to evaluate the language bias impact on orthodontic SRs.

DATA SOURCE

SRs published in high-impact orthodontic journals between 2017 and 2021 were retrieved through an electronic search of PubMed in June 2022. Additionally, Cochrane oral health group was searched for orthodontic systematic reviews published in the same period.

DATA COLLECTION AND ANALYSIS

Study selection and data extraction were performed by two authors. Multivariable logistic regression was implemented to explore the association of including non-English studies with the SRs characteristics. For the meta-epidemiological analysis, one meta-analysis from each SRs with at least three trials, including one non-English trial was extracted. The average difference in SMD was obtained using a random-effects meta-analysis.

RESULTS

174 SRs were included in this study. Almost one-quarter (n = 45/174, 26%) of these SRs included at least one non-English study. The association between SRs characteristics and including non-English studies was not statistically significant except for the restriction on language: the odds of including non-English studies reduced by 89% in SRs with a language restriction (OR: 0.11, 95%CI: 0.01 0.55, P< 0.01). Out of the sample, only fourteen meta-analyses were included in the meta-epidemiological analysis. The meta-epidemiological analysis revealed that non-English studies tended to overestimate the summary SMD by approximately 0.30, but this was not statistically significant when random-effects model was employed due to substantial statistical heterogeneity (ΔSMD = -0.29, 95%CI: -0.63 to 0.05, P = 0.37). As such, the overestimation of meta-analysis results by including non-English studies was statistically non-significant.

CONCLUSION

Language bias has non-negligible impact on the results of orthodontic SRs. Orthodontic systematic reviews should abstain from language restrictions and use sensitivity analysis to assess the impact of language on the conclusions, as non-English studies may have a lower quality.

"Over-reviewing" of research? An analysis of orthodontic reviews

INTRODUCTION

Research overviews may be undertaken to identify gaps in the literature, evaluate existing systematic reviews (SRs), and summarize evidence. This paper aims to profile overviews that have been conducted in orthodontics and related interventions since 2012 and to evaluate the degree of overlap among these overviews.

METHODS

Overviews published between January 1, 2012 and June 20, 2023 were identified using an electronic search involving Google Scholar and PubMed. A descriptive summary was produced, and citation matrices were used to evaluate the percentage of overlap between overviews using corrected covered area and covered area. This was classified as slight, moderate, high, or very high.

RESULTS

A total of 35 overviews were identified across a wide range of topics. Eight overviews included <10 SRs; 21 had 10-20 SRs; and 6 included >20 SRs (median no. of SRs per overview, 15; range, 3-62). Meta-analysis was conducted in only 5 overviews. Overlap between overviews on the same topic ranged from slight (2.7%) to very high (53.8%).

CONCLUSIONS

Almost all overview topics address treatments and their effects, with a wide variation in the number and quality of SRs included. There is considerable overlap in some orthodontic overviews, suggesting unnecessary duplication and research waste. Researchers should be encouraged to focus on primary data collection to add more high-quality data to SRs, which will ultimately enhance the yield from secondary and tertiary orthodontic research.

Do statistical heterogeneity methods impact the results of meta- analyses? A meta epidemiological study

BACKGROUND

Orthodontic systematic reviews (SRs) use different methods to pool the individual studies in a meta-analysis when indicated. However, the number of studies included in orthodontic meta-analyses is relatively small. This study aimed to evaluate the direction of estimate changes of orthodontic meta-analyses (MAs) using different between-study variance methods considering the level of heterogeneity when few trials were pooled.

METHODS

Search and study selection: Systematic reviews (SRs) published over the last three years, from the 1st of January 2020 to the 31st of December 2022, in six main orthodontic journals with at least one MA pooling five or lesser primary studies were identified. Data collection and analysis: Data were extracted from each eligible MA, which was replicated in a random effect model using DerSimonian and Laird (DL), Paule-Mandel (PM), Restricted maximum-likelihood (REML), Hartung Knapp and Sidik Jonkman (HKSJ) methods. The results were reported using median and interquartile range (IQR) for continuous data and frequencies for categorical data and analyzed using non-parametric tests. The Boruta algorithm was used to assess the significant predictors for the significant change in the confidence interval between the different methods compared to the DL method, which was only feasible using the HKSJ method.

RESULTS

146 MAs were included, most applying the random effect model (n = 111; 76%) and pooling continuous data using mean difference (n = 121; 83%). The median number of studies was three (range 2, 4), and the overall statistical heterogeneity (I2 ranged from 0 to 99% with a median of 68%). Close to 60% of the significant findings became non-significant when HKSJ was applied compared to the DL method and when the heterogeneity was present I2>0%. On the other hand, 30.43% of the non-significant meta-analyses using the DL method became significant when HKSJ was used when the heterogeneity was absent I2 = 0%.

CONCLUSION

Orthodontic MAs with few studies can produce different results based on the between-study variance method and the statistical heterogeneity level. Compared to DL, HKSJ method is overconservative when I2 is greater than 0% and may result in false positive findings when the heterogeneity is absent.

Effect of PRISMA 2009 on reporting quality in systematic reviews and meta-analyses in high-impact dental medicine journals between 1993-2018

INTRODUCTION

The PRISMA guidelines were published in 2009 to address inadequate reporting of key methodological details in systematic reviews and meta-analyses (SRs/MAs). This study sought to assess the impact of PRISMA on the quality of reporting in the full text of dental medicine journals.

METHODS

This study assessed the impact of PRISMA (2009) on thirteen methodological details in SRs/MAs published in the highest-impact dental medicine journals between 1993-2009 (n = 211) and 2012-2018 (n = 618). The study further examined the rate of described use of PRISMA in the abstract or full text of included studies published post- PRISMA and the impact of described use of PRISMA on level of reporting. This study also examined potential effects of inclusion of PRISMA in Instructions for Authors, along with study team characteristics.

RESULTS

The number of items reported in SRs/MAs increased following the publication of PRISMA (pre-PRISMA: M = 7.83, SD = 3.267; post-PRISMA: M = 10.55, SD = 1.4). Post-PRISMA, authors rarely mention PRISMA in abstracts (8.9%) and describe the use of PRISMA in the full text in 59.87% of SRs/MAs. The described use of PRISMA within the full text indicates that its intent (guidance for reporting) is not well understood, with over a third of SRs/MAs (35.6%) describing PRISMA as guiding the conduct of the review. However, any described use of PRISMA was associated with improved reporting. Among author team characteristics examined, only author team size had a positive relationship with improved reporting.

CONCLUSION

Following the 2009 publication of PRISMA, the level of reporting of key methodological details improved for systematic reviews/meta-analyses published in the highest-impact dental medicine journals. The positive relationship between reference to PRISMA in the full text and level of reporting provides further evidence of the impact of PRISMA on improving transparent reporting in dental medicine SRs/MAs.

Do pooled estimates from orthodontic meta-analyses change depending on the meta-analysis approach? A meta-epidemiological study

BACKGROUND

In meta-analyses involving a few trials, appropriate measures should be employed to assess between-study heterogeneity. When the number of studies is less than five and heterogeneity is evident, the Hartung and Knapp (HK) correction should be used. The aim of this study was to compare the reported estimates of published orthodontic meta-analyses with the pooled effect size estimates and prediction intervals (PI) calculated using eight heterogeneity estimators and corrected using the HK correction.

MATERIAL AND METHODS

Systematic reviews (SRs) published between 2017 and 2022 in four orthodontic journals and the Cochrane Database of Systematic Reviews with a meta-analysis of at least three studies were sourced. Study characteristics were extracted at the SR and the outcome/meta-analysis levels. All selected meta-analyses were re-analysed by fitting a random-effects model using eight different heterogeneity estimators, both with and without the HK correction. For each meta-analysis, the overall estimate, along with its standard error, the P-value, and the corresponding 95% confidence interval (CI), the between-study variance (tau2), the I2 statistic, and the PI were calculated.

RESULTS

One-hundred-six SRs were analysed. The most prevalent type of SR was non-Cochrane (95.3%), and the most used meta-analyses synthesis model was the random effect (83.0%). The median number of primary studies was 6 (interquartile range: 5, range: 3-45). The between-study variance was reported in most of the eligible meta-analyses (91.5%), but the type of heterogeneity estimator was reported in only one of them (0.9%). In 5 of 106 meta-analyses (4.7%), the HK correction was applied to adjust the CI of the pooled estimate. The percentage of statistically significant results, which became statistically non-significant, ranged from 16.7% to 25%, depending on the heterogeneity estimator. As the number of studies in a meta-analysis increased, the difference between corrected and uncorrected CIs reduced. Based on the PIs, more than half of the meta-analyses having statistically significant results are likely to change in the future, suggesting the result of the meta-analysis is not conclusive.

CONCLUSIONS

The statistical significance of pooled estimates from meta-analyses with at least three studies is sensitive to the HK correction, the heterogeneity variance estimator, and PIs. Clinicians should be aware of the clinical implications of not appropriately assessing the effect of the small number of studies and the between-study heterogeneity when interpreting results from meta-analyses.

Assessment of the efficacy of various maxillary molar intrusion therapies: a systematic review

AIMS

To systematically assess the efficacy of the various interventions used to intrude maxillary molars. Furthermore, to evaluate associated root resorption, stability of intrusion, subsequent vertical movement of mandibular molars, cost effectiveness, compliance, patient reported outcomes and adverse events.

METHODS

A pre-registered and comprehensive literature search of published and unpublished trials until March 22nd 2023 with no language restriction applied in PubMed/Medline, Embase, Scopus, DOSS, CENTRAL, CINAHL Plus with Full Text, Web of Science, Global Index Medicus, Dissertation and Theses Global, ClinicalTrials.gov, and Trip (PROSPERO: CRD42022310562). Randomized controlled trials involving a comparative assessment of treatment modalities used to intrude maxillary molars were included. Pre-piloted data extraction forms were used. The Cochrane Risk of Bias tool was used for risk of bias assessment, and The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system was used for certainty of evidence appraisal.

RESULTS

A total of 3986 records were identified through the electronic data search, of which 24 reports were sought for retrieval. Of these, 7 trials were included. One trial was judged at high risk of bias, while the others had some concerns. Based on individual small sample studies, maxillary molar intrusion was achieved using temporary anchorage devices (TADs) and rapid molar intruder appliance (RMI). It was also observed to a lesser extent with the use of open bite bionator (OBB) and posterior bite blocks. The molar intruder appliance and the posterior bite blocks (spring-loaded or magnetic) also intruded the lower molars. Root resorption was reported in two studies involving TADs. None of the identified studies involved a comparison of conventional and TAD-based treatments for intrusion of molars. No studies reported outcomes concerning stability, cost-effectiveness, compliance and patient-reported outcomes. Insufficient homogeneity between the included trials precluded quantitative synthesis. The level of evidence was very low.

CONCLUSIONS

Maxillary molar intrusion can be attained with different appliances (removable and fixed) and with the use of temporary anchorage devices. Posterior bite blocks (spring-loaded or magnetic) and the RMI offer the additional advantage of intruding the mandibular molars. However, stability of the achieved maxillary molar intrusion long term is unclear. Further high-quality randomized controlled trials are needed.

Reporting completeness of scoping reviews in orthodontic literature up to 2022. An empirical study

AIM

To assess the quality of reporting of Scoping Reviews (ScRs) in Orthodontics according to the PRISMA Extension Checklist for Scoping Reviews (PRISMA-ScR). Our secondary aim was to identify publication characteristics, such as year of publication, journal, inclusion of a reporting guideline, and study registration, associated with ScRs reporting quality.

MATERIALS AND METHODS

Pubmed, Scopus, and Web of Science Core Collection were searched as of 1 August 2022 for identification of orthodontic ScRs. This was supplemented by electronic searches within the contents of eleven specialty journals. The item-specific and overall reporting quality score of the examined orthodontic ScRs, based on the PRISMA Extension Checklist for Scoping Reviews were recorded. Association of reporting quality score with publication characteristics was further examined.

RESULTS

A total of 40 ScRs were identified and included, with a mean reporting quality score of 73.0 per cent (standard deviation = 14). The majority of studies were published from 2020 onwards (32/40; 80.0%). Of the most adequately reported items were the summary of the evidence description in the Discussion (38/40; 95.0%) and the selection of the sources of evidence in the Results section (34/40; 85.0%). Protocol registration and reporting of limitations were missed in almost half of the ScRs (19/40; 47.5%), while less than half studies were adequately justified (18/40; 45.0%). According to the multivariable linear regression, adherence to appropriate reporting guidelines resulted in improved reporting quality score by 10 per cent (β-coefficient: 0.10; 95% CI: 0.002, 0.19; P = 0.04), conditional on year and journal of publication. Year, journal of publication, and registration practices did not appear as significant predictors (P > 0.05 in all instances).

CONCLUSIONS

The reporting quality of the examined orthodontic ScRs was suboptimal, with questionable justification for their conduct and certain items being mostly affected.

Scoping reviews in orthodontics: are they justified?

BACKGROUND

Scoping Reviews (ScRs) have emerged in the orthodontic literature as a new methodological perspective to collate and summarize scientific evidence. The aim of the present study was to identify and record the proportion of Scoping Reviews in orthodontics that have been clearly and adequately justified, based on the methodological framework of such types of reviews. Associations with a number of publication characteristics were also sought. Three major databases, namely PubMed, Scopus and Web of Science Core Collection, as well as 11 specialty orthodontic journals were electronically sought from inception until August 1, 2022, for ScRs. The primary outcome pertained to whether the published reports of the ScRs included an appropriate justification and explanation for the selection of this kind of knowledge synthesis methodology. Potential association with year, journal, continent of authorship, number of authors, methodologist involvement, appropriate reporting guidelines and registration practices followed were explored.

RESULTS

A total of 40 ScRs were eligible for inclusion, with the majority not being adequately justified (22/40; 55.0%). The majority of studies were published from 2020 onward (32/40; 80.0%). The regression model did not reveal any significant association between justification of ScRs and a number of publication characteristics (p > 0.05 at all levels).

CONCLUSIONS

Less than half of the included ScRs were adequately justified in terms of selection of the appropriate synthesis methodology. Awareness should be raised in the scientific community regarding the correctness of the use of this newly emerging type of study in orthodontics, to safeguard against any trace of research waste.

Comparing the Effect of Miniscrew-Supported and Conventional Maxillary Incisor Intrusion on the Inclination of Maxillary Incisors and Molars - A Systematic Review and Meta-Analysis

Objective

The objective of this study was to compare the effect of miniscrew-supported maxillary incisor intrusion and conventional intrusion mechanics on maxillary incisors and molar inclination.

Material and Methods

Search databases (PubMed, Scopus, Web of Science, Embase, EBSCOhost, and the Cochrane Library) were searched for randomized trials on intrusion of maxillary incisors via miniscrew-supported and conventional mechanics. The revised Cochrane risk-of-bias tool for randomized trials (RoB 2.0) was used. Five outcomes ([i] inclination change of upper incisors, [ii] inclination change of upper molars, [iii] intrusion of incisors, [iv] vertical change in upper first molars, and [v] overbite correction achieved) were statistically pooled using Review Manager 5.3. Subgroup analysis was conducted to receive sturdiness in meta-analysis. The quality of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation.

Results

Out of 1777 studies, 7 were finally subjected to quality assessment, and 6 were included in the meta-analysis. The incisor inclination following maxillary incisor intrusion increased in miniscrew-supported intrusion in comparison to Connecticut intrusion arch (CTA) subgroup with standard mean difference of 0.66 mm (95% confidence interval = 0.16, 1.03, I2 = 0%). All the included studies showed an increase in molar inclination (distal tipping) in the CTA subgroup compared to the micro-implant group. Of all the seven included studies, only one study was identified with some concerns for the risk of bias, and the other six were judged to have an overall high risk of bias.

Conclusion

The incisal proclination during deep-bite correction by miniscrew-supported incisal intrusion is more than that in the CTA subgroup; however, the difference may not be clinically very relevant. There is a very low quality of evidence in favor of miniscrew-supported intrusion as compared to conventional intrusion, necessitating the need for good-quality trials.

Reporting of the methodological quality of search strategies in orthodontic quantitative systematic reviews

BACKGROUND

This study aimed to assess the reporting of the methodological quality of search strategies undertaken in orthodontic quantitative systematic reviews (SRs) and hence their reproducibility.

MATERIALS AND METHODS

A search of a single electronic database (Medline via PubMed) was undertaken to identify interventional orthodontic SRs with meta-analysis published within a 10-year period. The Cochrane Library of Systematic Reviews was also sourced. Full articles were reviewed by two assessors against the eligibility criteria. The reporting quality of each search strategy was assessed using a previously validated checklist with a score of 1 or 2 given for each of the eight items. Cumulative totals were calculated. Guided by previous research, the authors agreed the following cut-offs to categorize the overall level of quality: 8-10 (poor), 10-12 (fair), and greater than 13 (good).

RESULTS

A total of 127 SRs were analysed. The overall median quality score for the reporting of the search strategy was 14 [interquartile range (IQR): 13-15]. Cochrane SRs and those originating in Europe received higher aggregate scores, whereas no difference was evident based on Prospero registration. The continent of the corresponding author predicated the overall score. Non-Cochrane reviews achieved lower overall scores compared to Cochrane reviews (-1.0, 95% confidence interval: -1.65, -0.34, P = 0.003). The most frequently searched database was EMBASE (N = 93) and the median number of authors was 5 (IQR 4-6). Authors of 26.8% of SRs searched the grey literature. Language restrictions were applied to the search strategies of 88 (69.3%) SRs.

CONCLUSIONS

The reporting quality of search strategies undertaken in orthodontic SRs is at a good level but differences between Cochrane and non-Cochrane reviews currently exist. The reporting of searching of the grey literature and application of no language restrictions can be improved.

Use of quality assessment tools within systematic reviews in orthodontics during the last decade: looking for a threshold?

OBJECTIVE

To record the prevalence and extent of use of quality assessment/ risk of bias tools in orthodontic systematic reviews and to identify whether systematic reviews authors stipulated a threshold during the evaluation process of the primary studies included in systematic reviews, published across the previous decade and until now. Associations with publication characteristics including the journal of publication, year, the inclusion of a meta-analysis, design of primary studies and others, were sought.

MATERIALS AND METHODS

Electronic search within 6 orthodontic journals and the Cochrane Database of Systematic Reviews was conducted to identify relevant systematic reviews from 1 January 2010 and 31 December 2020. The outcomes of interest pertained to the use, type and extent of quality appraisal/ risk of bias tools utilized as a standard process within the systematic reviews, and also whether a threshold had been stipulated by the systematic reviews authors. Predictor variables included journal, year of publication, geographic region, number of authors, involvement of a methodologist, type of systematic reviews, inclusion of meta-analysis, type/design of primary studies.

RESULTS

A total of 262 systematic reviews were eligible for inclusion, with 41 quality appraisal/ risk of bias sets of tools being described either jointly or in isolation. One-third of the systematic reviews of the present sample (88/262; 33.6%) included a threshold, while this was mostly represented by the stipulation of sensitivity analyses in this respect (64/88; 72.8%). Journal of publication (non-Cochrane systematic reviews versus Cochrane systematic reviews: adjusted odds ratio, OR: 0.04, 95%CI: 0.01, 0.16; P < 0.001) and inclusion of a meta-analysis (adjusted OR: 8.76; 95%CI: 4.18, 18.37; P < 0.001), were identified as significant predictors for preplanning of thresholds.

CONCLUSIONS AND IMPLICATIONS

Quality assessment tools for primary studies are largely used and varied in orthodontic systematic reviews, while a threshold-level has been stipulated in only one third. Additional efforts should be endorsed by the scientific community, to embrace more straightforward adoption of the most rigorous reporting guidelines in this respect.

Published evidence regarding association between malocclusion and orthodontic treatment on oral health is inconclusive

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION

Macey R, Thiruvenkatachari B, O'Brien K, Batista KBSL. Do malocclusion and orthodontic treatment impact oral health? A systematic review and meta-analysis. Am J Orthod Dentofacial Orthop. 2020;157(6):738-744.e10. doi:10.1016/j.ajodo.2020.01.015.

SOURCE OF FUNDING

Government: Public Health England or the National Health Service.

TYPE OF STUDY/DESIGN

Systematic review with meta-analysis of data.

Reporting, interpretation, and extrapolation issues (SPIN) in abstracts of orthodontic meta-analyses published from 2000 to 2020

AIM

To assess the prevalence of and identify factors associated with SPIN in abstracts of orthodontic meta-analyses.

MATERIALS AND METHODS

Electronic search was performed within the contents of five orthodontic journals and the Cochrane Database of Systematic Reviews (CDSR) to identify meta-analyses of studies involving humans, from 1 January 2000 until 31 August 2020. Inclusion of SPIN in the abstract of meta-analyses, defined as misleading reporting, misleading interpretation, and inappropriate extrapolation of the findings, was documented. Extent of SPIN and associations with journal and year of publication, type of study, number of authors, continent of authorship, methodologist involvement, funding, and significance of the primary outcome were investigated.

RESULTS

One hundred and nine meta-analyses were identified, with the highest proportion being published in the European Journal of Orthodontics (EJO: 31/109; 28.4%). Inclusion of SPIN, in at least one domain, was recorded in nearly half (53/109; 48.6%) of the studies, of which 30 (56.6%) included 2 or more domains of SPIN. Meta-analyses of observational studies presented 1.66 times higher risk for including SPIN in their abstracts compared with interventional ones [95% confidence intervals (CIs): 1.14, 2.40; P = 0.007], after adjusting for a number of predictors. Studies with a large number of authors (≥6) presented 1.76 times higher risk of SPIN (≥6 versus 1-3: 95% CIs: 1.04, 2.97; Wald test, P = 0.021), conditional on the pre-defined predictors.

CONCLUSIONS

Flaws in the reporting and interpretation of the findings of abstracts of meta-analyses, as framed by inclusion of SPIN are persistent in orthodontic research, being more prevalent in meta-analyses of observational studies. Consistent, multidirectional efforts should be endorsed to improve the quality of the disseminated research findings.

Outcome reporting discrepancies between trial entries and published final reports of orthodontic randomized controlled trials

BACKGROUND/OBJECTIVES

The aim of this study was to identify outcome-related discrepancies between registry trial entries and final published reports in orthodontic randomized controlled trials (RCTs). The percentage of registered orthodontic RCTs was also recorded.

MATERIALS/METHOD

Five trial registries, ClinicalTrials.gov (https://clinicaltrials.gov/), International Standard Randomised Controlled Trial Number registry (http://www.isrctn.com/), European Union Clinical Trials Register (https://www.clinicaltrialsregister.eu/), Australia New Zealand Clinical Trials Registry (http://www.anzctr.org.au/) and Clinical Trials Registry of India (www.ctri.nic.in/) were searched up to April 2018 in order to identify completed orthodontic RCTs. The unique trial identifier, the title and authors name were used to search for publications based on entries within Google (https://www.google.com), Google Scholar (https://scholar.google.gr/) and MEDLINE via PubMed (https://www.ncbi.nlm.nih.gov/pubmed/). Outcome reporting discrepancies and a number of other entry/publication characteristics were recorded including timing of registration, type of journal/publication, significance of the primary outcome in the final report. The number of trials registered among the total number of published RCTs in orthodontics was recorded within the time span assessed.

RESULTS

One hundred and twenty-four entries were identified for completed orthodontic RCTs, whereas 53 of those were related to published final reports. Outcome reporting discrepancies were ascertained for 47 per cent of publications (n = 2 5); discrepancies were more prevalent for non-primary outcomes (n = 21, 40 per cent). Only 16 per cent of the published orthodontic RCTs had been registered.

LIMITATIONS

Only a subset of trial entries were assessed as these were related to publication records.

CONCLUSIONS/IMPLICATIONS

Registration of clinical trials in orthodontics remains far from universal. A significant level of outcome reporting discrepancy was observed within this subset of registered trials.

Evaluation of the effectiveness of a tailored mobile application in increasing the duration of wear of thermoplastic retainers: a randomized controlled trial

Background

The ‘My Retainers’ mobile application is a patient-informed intervention designed to enhance removable retainer wear and associated patient experiences during the retention phase.

Objectives

To evaluate the effect of receiving the ‘My Retainers’ application on objectively assessed thermoplastic retainer (TPR) wear time, stability, periodontal outcomes, patient experiences, and knowledge related to retainers.

Materials and methods

Eighty-four participants planned for removable retention with TPRs were assigned either to receive the ‘My Retainers’ application or to control not receiving electronic reminders during the 3-month period. Randomization was based on computer-generated random numbers and allocation was concealed using opaque, sealed envelopes. The primary outcome was objectively assessed retainer wear recorded using an embedded TheraMon® micro-electronic sensor. Secondary outcomes, including irregularity of the maxillary and mandibular incisors, plaque levels, bleeding on probing and probing depth, were assessed at baseline and 3-month follow-up; and analysed using a series of mixed models. Experiences and knowledge related to orthodontic retainers were recorded using questionnaires. The outcome assessor was blinded when possible.

Results

Receipt of the mobile application resulted in slightly higher median wear time (0.91 hours/day); however, this difference was not statistically significant (P = 0.56; 95% confidence interval [CI]: −2.19, 4.01). No significant differences were found between the treatment groups in terms of stability (P = 0.92; 95% CI: −0.03, 0.04), plaque levels (P = 0.44; 95% CI: −0.07, 0.03), bleeding on probing (P = 0.61; 95% CI: −0.05, 0.03) and probing depth (P = 0.79; 95% CI: −0.09, 0.07). Furthermore, similar levels of patient experiences (P = 0.94) and knowledge related to retainers (P = 0.26) were found. However, marginally better levels of knowledge were identified in the intervention group. No harms were observed.

Limitations

A relatively short follow-up period with the study confined to a single-center in a university-based hospital.

Conclusions

Provision of the bespoke ‘My Retainers’ application did not lead to an improvement in adherence with TPR wear over a 3-month follow-up period. Further refinement and research are required to develop and investigate means of enhancing adherence levels.

Clinical registration

NCT03224481.

Systematic reviews in orthodontics: Impact of the PRISMA for Abstracts checklist on completeness of reporting

INTRODUCTION

This study evaluated and compared the completeness of reporting of abstracts of orthodontics systematic reviews before and after the publication of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for Abstracts Checklist (PRISMA-A).

METHODS

Abstracts of systematic reviews and meta-analyses in orthodontics published in PubMed, Latin American and Caribbean Health Sciences Literature, and the Cochrane Database of Systematic Reviews databases before March 23, 2018, that met the predefined inclusion and exclusion criteria, were evaluated using the 12 items of PRISMA-A, scoring each item from 0 to 2. Abstracts were classified into 2 groups: before and after publication of the PRISMA-A checklist. Three calibrated evaluators (intraclass correlation coefficient and kappa > 0.8) assessed the scores for compliance with the checklist. The number of authors, country of affiliation of the first author, performance of meta-analysis, and topic of the article were recorded. A regression analysis was performed to assess the associations between abstract characteristics and the PRISMA-A scores.

RESULTS

Of 1034 abstracts evaluated, 389 were included in the analysis. The mean PRISMA-A score was 53.39 (95% CI, 51.83-54.96). The overall score for studies published after the publication of the checklist was significantly higher than for studies published before (P ≤ 0.0001). The components returning significantly higher scores after publication of PRISMA-A were title (P = 0.024), information from databases (P = 0.026), risk of bias (P ≤ 0.0001), included studies (P ≤ 0.0001), synthesis of results (P ≤ 0.0001), interpretation of results (P = 0.035), financing and conflict of interest (P ≤ 0.0001), and registration (P ≤ 0.0001). These results showed the positive effect of PRISMA-A had on the quality of reporting of orthodontics systematic reviews. Nevertheless, the poor adherence revealed that there is still need for improvement in the quality of abstract reporting.

CONCLUSIONS

The quality of reporting of abstracts of orthodontic systematic reviews and meta-analyses increased after the introduction of PRISMA-A.

Three-dimensional stereophotogrammetric analysis of nasolabial soft tissue effects of rapid maxillary expansion: a systematic review of clinical trials

The aim of this systematic review is to analyse the quality and clinical evidence in the literature analysing, through 3D stereophotogrammetry, the nasolabial soft tissue modifications that may occur after rapid maxillary expansion (RME). This systematic literature review was based on the PRISMA-P statement and was registered in the PROSPERO database with the following protocol ID: CRD42017079875. Pubmed, Cochrane, EBSCO, Scopus, Web of Science databases were searched with no restriction of year or publication status. Selection criteria were: randomised clinical trials, controlled clinical trials, cohort studies, cross-sectional studies, case-control studies on patients with unilateral/bilateral crossbite, transverse maxillary deficiency and crowding, treated with RME and monitored by 3D stereophotogrammetry. 652 articles were retrieved in the initial search. After the review process, 11 full-text articles met inclusion criteria. After the evaluation process, 4 publications were included for the present literature review. Due to the heterogeneous methodology meta-analysis was not possible; consequently, a systematic assessment of the studies and summary of the findings from the available evidence were used to answer the research question. The maximum widening of the alar cartilage is 1.41 ± 0.95 mm, whose clinical significance is open to question. The effect of RME on the mouth width remains controversial. In Altindis et al., the difference between pre-treatment and post-treatment mouth width (1.80 mm increment in the banded RME group) was statistically significant, while in Baysal 1.86 mm was considered a non-significant value. Inconsistencies and limitations in the study population and measurement protocols were detected between studies. These data underline the necessity for updated guidelines that allow to standardise, for this type of study, sample selection, measurement methods and collection of results.

Increasing the Value of Orthodontic Research Through the Use of Dental Patient-Reported Outcomes

Ten years ago, Chalmers and Glasziou pointed out in the Lancet that 85% of all biomedical research was being avoidably wasted because of imbalanced research question/outcome selection, as well as poor study design, execution, and reporting. According to findings of recent "research on research" studies, a high level of such kind of avoidable waste should also exist in orthodontic research. This warrants efforts to improve each stage of the research production and reporting process. Nowadays, patients' psychosocial function is considered a core element of oral health. Also, their treatment needs and preferences have formed a main component of evidence-based dentistry. Therefore, to achieve shared decision-making, orthodontists need to have an adequate understanding of each patient's values and perceptions. In this context, orthodontic research should be patient-centered so that the knowledge and perception gaps between clinicians and patients can be reduced, and research evidence that is suitable for patients to understand can be provided. In addition, patient-centered outcomes that can reflect patients' perceptions and psychosocial status should be widely used. However, recent scoping reviews have shown that during the past decade, patient-centered outcomes including those regarding adverse effects, health service resource utilization, and quality of life have remained under-represented in orthodontic trials. Thus, the use of dental patient-reported outcomes and dental patient-reported outcome measures should be promoted to facilitate the provision of a patient-centered evidence base, reduce the avoidable waste related to research question/outcome selection, and thereby increase the value of orthodontic research.

Heterogeneity in Cochrane and non-Cochrane meta-analyses in orthodontics

OBJECTIVES

Heterogeneity describes the percentage of variability across the study effects that can be attributed to between-study differences in a meta-analysis. The aim of this project was to explore the magnitude of heterogeneity in Cochrane and non-Cochrane meta-analyses in orthodontic research and to identify possible associations between heterogeneity (I²) and a number of study characteristics including number of studies, type of outcome and type of analysis.

METHODS

The contents of five major orthodontic journals and the Cochrane Database of Systematic Reviews were electronically searched from January 2000 to December 2017 to identify Systematic Reviews (SRs) with at least one meta-analysis. Included records were screened for reporting of I² classified into four categories: 0%, 1-29%, 30-59%, 60-100%. Associations between I² and review-level and synthesis-level characteristics were tested. Univariable and multivariable mixed effects ordinal logistic regression was used to identify significant predictors for statistical heterogeneity.

RESULTS

A total of 72 SRs comprising 391 meta-analyses were included with the majority based on non-Cochrane reviews (n = 54, 75%). Overall, 125 meta-analyses (32%) reported heterogeneity explained by chance (I² = 0%), whereas high values of I² (∼60-100%) were seen in 152 syntheses (39%). In the multivariable analysis, inclusion of each additional study within the synthesis presented 20% higher odds for substantial/considerable heterogeneity compared to lower heterogeneity categories (OR = 1.20; 95%CIs: 1.09, 1.31; p < 0.001). Use of fixed effect analysis (OR = 0.25; 95%CIs: 0.12, 0.55; p = 0.001) was associated with significantly lower odds. Cochrane versus non-Cochrane meta-analyses were not associated with higher odds for substantial/considerable heterogeneity (OR = 2.81; 95%CIs: 0.53, 14.91; p = 0.22).

CONCLUSIONS

Substantial statistical heterogeneity is present within a considerable number of orthodontic meta-analyses. Further efforts should be made to improve understanding of decisions to undertake meta-analyses and selection of studies eligible for inclusion.

CLINICAL SIGNIFICANCE

The consistency of meta-analyses could be improved with more careful consideration of individual study characteristics. Reduced heterogeneity in meta-analyses will ensue more solid evidence based decisions for clinical practice.

Clinical evaluation of marketed orthodontic products: are researchers behind the times? A meta-epidemiological study

BACKGROUND

The role of marketing and industry in the treatment decisions of orthodontists has received increasing attention in recent years with clinical research typically undertaken subsequent to established use of these devices and often failing to confirm the promise of manufacturers' claims. This meta-epidemiological study was undertaken to assess the proportion of clinical trials in orthodontics evaluating commercially marketed products and to evaluate the direction of the results of these studies.

METHODS

Electronic searching was undertaken to identify randomized controlled trials (RCTs) published over a 5-year period (1 January 2012 to 31 December 2016). Data obtained included the type of marketed intervention, direction of effect and declaration of both industry sponsorship and conflict of interest.

RESULTS

Eighty-four RCTs published in 23 scientific journals were included with the highest percentage in the American Journal of Dentofacial Orthopedics (AJO-DO) (23.8%), followed by the European Journal of Orthodontics (EJO) (14.3%), Journal of Orthodontics (JO) (10.7%) and Angle Orthodontist (AO) (10.7%). Overall, 45% (38/84) of clinical trials assessed involved analysis of marketed products after their introduction. Interventions to improve oral health or circumvent the risk of iatrogenic damage, such as white spot lesions, were most commonly assessed (15.8%), with the relative merits of non-surgical adjuncts (14.1%) and other orthodontic auxiliaries (13.1%) also frequently evaluated. In 44% of RCTs, a positive effect of the marketed intervention was not reported. Industry sponsorship of the research was declared in 9.5% RCTs. No significant associations between the direction of the effect and both declaration of industry sponsorship (p = 0.56) and conflict of interest (p = 0.96) were detected. Moreover, for marketed and non-marketed products, no significant associations for both declaration of industry sponsorship (p = 0.44) and conflict of interest (p = 0.28) were found.

CONCLUSIONS

Almost half of orthodontic clinical trials over the past 5 years involve analysis of marketed products after their introduction. The results highlight a potential source of waste in orthodontic research emanating from existing approaches to licensing and marketing of orthodontic products.

The effect of bracket ligation on the periodontal status of adolescents undergoing orthodontic treatment. A systematic review and meta-analysis

INTRODUCTION/OBJECTIVES

This systematic review aimed to critically appraise the evidence regarding the effect of bracket ligation type on the periodontal conditions of adolescents undergoing orthodontic treatment.

DATA

Search terms included randomized controlled trial (RCTs), controlled clinical trials, ligation, bracket, periodontal, inflammation. Risk of bias assessment was made using the Cochrane risk of bias tool and the quality of evidence was assessed with GRADE.

SOURCES

Electronic Database search of published and unpublished literature was performed without language restriction in May 25, 2016 (MEDLINE via Pubmed, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Clinical Trials.gov and National Research Register).

STUDY SELECTION

Of 140 articles initially retrieved, 8 were eligible for inclusion in the systematic review, while 4 RCTs with unclear risk of bias were included in the quantitative synthesis, all comparing self-ligating to conventional steel ligated brackets. Random effects meta-analyses were implemented. At 4-6 weeks after bracket placement there was no evidence to support the use of either type of bracket for achieving improved plaque- (PI) and gingival index (GI). At 3-6 months, there was scarce evidence of greater PI increase for conventional brackets. GI and pocket depth pooled estimates did not reveal significant differences between the two systems. The quality of the evidence was moderate according to GRADE for all outcomes.

CONCLUSIONS

Overall, non-significant differences on the periodontal status of adolescents undergoing orthodontic treatment with either conventional or self-ligating brackets were detected.

CLINICAL SIGNIFICANCE

The periodontal status of adolescents undergoing orthodontic treatment is of considerable importance. The synthesis of the available evidence on oral hygiene related factors will provide insights to best clinical practice during the course of orthodontic treatment.

The effects of fixed and removable orthodontic retainers: a systematic review

OBJECTIVE

In the view of the widespread acceptance of indefinite retention, it is important to determine the effects of fixed and removable orthodontic retainers on periodontal health, survival and failure rates of retainers, cost-effectiveness, and impact of orthodontic retainers on patient-reported outcomes.

METHODS

A comprehensive literature search was undertaken based on a defined electronic and gray literature search strategy (

PROSPERO

CRD42015029169). The following databases were searched (up to October 2015); MEDLINE via OVID, PubMed, the Cochrane Central Register of Controlled Trials, LILACS, BBO, ClinicalTrials.gov, the National Research Register, and ProQuest Dissertation and Thesis database. Randomized and non-randomized controlled clinical trials, prospective cohort studies, and case series (minimum sample size of 20) with minimum follow-up periods of 6 months reporting periodontal health, survival and failure rates of retainers, cost-effectiveness, and impact of orthodontic retainers on patient-reported outcomes were identified. The Cochrane Collaboration's Risk of Bias tool and Newcastle-Ottawa Scale were used to assess the quality of included trials.

RESULTS

Twenty-four studies were identified, 18 randomized controlled trials and 6 prospective cohort studies. Of these, only 16 were deemed to be of high quality. Meta-analysis was unfeasible due to considerable clinical heterogeneity and variations in outcome measures. The mean failure risk for mandibular stainless steel fixed retainers bonded from canine to canine was 0.29 (95 % confidence interval [CI] 0.26, 0.33) and for those bonded to canines only was 0.25 (95 % CI: 0.16, 0.33). A meta-regression suggested that failure of fixed stainless steel mandibular retainers was not directly related to the period elapsed since placement (P = 0.938).

CONCLUSION

Further well-designed prospective studies are needed to elucidate the benefits and potential harms associated with orthodontic retainers.

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.