A case study evaluating the effect of clustering, publication bias, and heterogeneity on the meta-analysis estimates in implant dentistry.

Meta-analyses may provide imprecise estimates when important meta-analysis parameters are not considered during the synthesis. The aim of this case study was to highlight the influence of meta-analysis parameters that can affect reported estimates using as an example pre-existing meta-analyses on the association between implant survival and sinus membrane perforation. PubMed was searched on 7 July 2021 for meta-analyses comparing implant failure in perforated and non-perforated sinus membranes. Primary studies identified in these meta-analyses were combined in a new random-effects model with odds ratios (ORs), confidence intervals (CIs), and prediction intervals reported. Using this new meta-analysis, further meta-analyses were then undertaken considering the clinical, methodological, and statistical heterogeneity of the primary studies, publication bias, and clustering effects. The meta-analyses with the greatest number and more homogeneous studies provided lower odds of implant failure in non-perforated sites (OR 0.49, 95 % CI = [0.26, 0.92]). However, when considering heterogeneity, publication bias, and clustering (number of implants), the confidence in these results was reduced. Interpretation of estimates reported in systematic reviews can vary depending on the assumptions made in the meta-analysis. Users of these analyses need to carefully consider the impact of heterogeneity, publication bias, and clustering, which can affect the size, direction, and interpretation of the reported estimates.

Clinical evaluation of marketed and non-marketed orthodontic products: are researchers now ahead of the times? A meta-epidemiological study.

BACKGROUND: The advertisement and adoption of untested orthodontic products is common. This study aimed to provide an update regarding the prevalence of clinical trials in orthodontics evaluating commercially marketed products. Associations between marketed/non-marketed products and study characteristics such as direction of effect, declaration of conflict of interest and industry sponsorship were evaluated. In addition, within the marketed products associations between direction of effect and study characteristics were explored. MATERIAL AND METHODS: Electronic searching of a single database (Medline via PubMed) was undertaken to identify Randomized controlled trials (RCTs) published over a 5-year period (1st January 2017 to 31st December 2021). Descriptive statistics and associations between trial characteristics were explored. RESULTS: 196 RCTs were analysed. RCTs were frequently published in Angle Orthodontist (18.4%), American Journal of Orthodontics and Dentofacial Orthopedics (14.8%) and European Journal of Orthodontics (13.3%). 65.3% (128/196) of trials assessed marketed products after their introduction. The majority of trials assessed interventions to improve treatment efficiency (33.7%). Growth modification appliances were typically analysed in non-marketed compared to marketed products. An association between the type of product (marketed vs non-marketed) and both the declaration of conflict of interest and industry sponsorship was detected. For individual RCTs assessing marketed products either a positive effect (45.3%) or equivalence between interventions or between intervention and untreated control (47.7%) was evident. In 27% of these trials either no conflict of interest or industry funding was not clearly declared. Within the marketed products, no association between the direction of the effect and conflict of interest or funding was detected. CONCLUSIONS: The analysis of marketed orthodontic products after their introduction is still common practice. To reduce research waste, collaboration prior to the licensing and marketing of orthodontic products between researchers, industry and manufacturers is recommended.

Clear aligner therapy practice among orthodontists in the United Kingdom and the Republic of Ireland: A cross-sectional survey of the British Orthodontic Society membership.

OBJECTIVE: To investigate clear aligner therapy (CAT) practice among orthodontists in the British Orthodontic Society (BOS). DESIGN: A cross-sectional online survey. METHODS: An electronic survey was distributed to members of the BOS in 2022. The survey comprised questions regarding respondent demographics, general use of CAT, the choice of proprietary CAT appliances, CAT planning, case selection, treatment protocols and orthodontist-reported CAT problems. RESULTS: Overall, 233 (19.5%) responses were received with the majority (n = 121, 53.1%) being female. Most respondents reported practising in England (n = 171, 74.7%). The majority (n = 177, 77.3%) indicated that they used CAT in their practice, with 48.1% (n = 81) treating 1-20 patients with CAT annually. The most frequently prescribed CAT system was Invisalign (n = 138, 81.2%). One to three changes to the initial digital treatment plan were made by 72.9% (n = 121) with final tooth positions being the most common reason for adjustment (64.4%). Most (n = 97, 60.3%) rarely or never performed premolar extractions with CAT. Of the respondents, 23 12.7%) reported that they always or mostly used a remote monitoring system in conjunction with CAT, with a wide range of aligner change protocols reported. The median number of months required to complete non-extraction CAT reported by the respondents was 12. Most respondents (n = 77, 51.7%) did not feel that CAT provides superior outcomes compared with fixed appliance therapy. CONCLUSION: CAT practice varied widely among the surveyed orthodontists. A predilection for the use of Invisalign and utility in less severe cases was noted.

Does the quality of orthodontic studies influence their Altmetric Attention Score?

Objective: The aim of this study was to determine whether an association between study quality, other study characteristics, and Altmetric Attention Scores (AASs) existed in orthodontic studies. Methods: The Scopus database was searched to identify orthodontic studies published between January 1, 2017, and December 31, 2019. Articles that satisfied the eligibility criteria were included in this study. Study characteristics, including study quality were extracted and entered into a pre-pilot data collection sheet. Descriptive statistics were calculated. On an exploratory basis, random forest and gradient boosting machine learning algorithms were used to examine the influence of article characteristics on AAS. Results: In total, 586 studies with an AAS were analyzed. Overall, the mean AAS of the samples was 5. Twitter was the most popular social media platform for publicizing studies, accounting for 53.7%. In terms of study quality, only 19.1% of the studies were rated as having a high level of quality, with 41.8% of the studies deemed moderate quality. The type of social media platform, number of citations, impact factor, and study type were among the most influential characteristics of AAS in both models. In contrast, study quality was one of the least influential characteristics on the AAS. Conclusions: Social media platforms contributed the most to the AAS for orthodontic studies, whereas study quality had little impact on the AAS.

Periodontal outcomes associated with impacted maxillary central incisor and canine teeth following surgical exposure and orthodontic alignment: a systematic review and meta-analysis.

BACKGROUND: Maxillary incisor and canine teeth are commonly impacted and require multidisciplinary treatment to accommodate them in the dental arch. OBJECTIVES: To assess the periodontal outcomes of impacted maxillary central incisor and canine teeth, which have been successfully aligned in the arch following surgical exposure and orthodontic traction with fixed appliance therapy. SEARCH METHODS: Systematic literature searches without restrictions were undertaken in eight databases. SELECTION CRITERIA: Studies reporting surgical interventions in combination with orthodontic traction with fixed appliance therapy to align impacted maxillary incisors or canines published up to January 2023. DATA COLLECTION: Duplicate independent study selection, data extraction, and risk of bias assessment. ANALYSIS: Random-effects meta-analyses of aggregate data. RESULTS: Twenty-three studies (21 retrospective and 2 prospective) were included in the final analysis. Three studies reported outcomes for maxillary central incisors and 20 reported outcomes for maxillary canines. For maxillary central incisors, all three studies were rated as being at moderate risk of bias. For maxillary canines, 17 studies and 1 study were rated at moderate and high risk of bias, respectively. Both prospective studies were rated at a low risk of bias. Meta-analyses comparing aligned impacted maxillary canines to their non-impacted contralateral counterparts found the former had increased Plaque Index scores (mean difference [MD] 0.19; 95% confidence interval [CI] 0.03, 0.35; P = 0.03), increased clinical attachment loss (MD 0.40 mm; 95% CI 0.17, 0.63; P = 0.01), increased pocket probing depth (MD 0.18 mm; 95% CI 0.07, 0.28; P = 0.001), increased bone loss (MD 0.51 mm; 95% CI 0.31, 0.72; P < 0.001), and reduced keratinized gingival width (MD -0.31 mm; 95% CI -0.61, -0.01; P = 0.04). CONCLUSIONS: Limited evidence suggests that surgical exposure and orthodontic alignment of impacted maxillary central incisor or canine teeth, results in modest adverse effects in the periodontium. These findings should be viewed with caution as our certainty for these outcomes is very low to low due to the bias and heterogeneity. Further well-conducted studies reporting patient centred outcomes are required. REGISTRATION: PROSPERO (CRD42020225639).

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.

The reporting of study limitations in randomized controlled trials published in the leading dental journals: Is it sufficient?

OBJECTIVES: Adequate reporting of limitations is crucial to enable clinicians to accurately interpret the clinical trial findings. This meta-epidemiological study aimed to evaluate whether study limitations are reported in full-text articles of randomized controlled trials (RCTs) published in the leading dental journals. Associations between the trial characteristics and the reporting of limitations were also explored. METHODS: RCTs published between 1st January and 31st December in the years 2011, 2016 and 2021 were identified from the 12 high impact factor dental journals (general and specialty). RCT characteristics were extracted, and reporting of limitations was recorded for the selected studies. Descriptive statistics were calculated for trial and limitations related characteristics. Univariable ordinal logistic regression models were fit to explore univariable associations between trial characteristics and reporting of limitations. RESULTS: Two hundred and sixty-seven trials were included and analyzed. Most RCTs were published in 2021 (40.8%), had authors based in Europe (50.2%), did not have a statistician involved (88.8%) and assessed a procedure/method intervention type (40.5%). The reporting of trial limitations was generally sub-optimal. More recent trials and studies with a published protocol were associated with better reporting of limitations. The type of journal was a significant predictor for limitation reporting. CONCLUSIONS: Within this study, the clear reporting of study limitations in the manuscripts of dental RCTs is sub-optimal and requires improvement. CLINICAL SIGNIFICANCE: The reporting of limitations should not be viewed as a weakness of a trial but due diligence, so clinicians can fully interpret the impact of these limitations on both the validity and generalisability of the results.

The quality and content of websites in the UK advertising aligner therapy: are standards being met?

Aims To evaluate the quality of information and compliance with General Dental Council (GDC) ethical advertising guidelines for English-language orthodontic websites providing orthodontic treatment with aligners in the United Kingdom (UK).Materials and methods The term 'orthodontic aligners or braces' was entered into the Google online search engine. The first 100 English language orthodontic websites (practice or company) were pooled. Both the quality (DISCERN instrument) and compliance with GDC ethical advertising guidelines were assessed. Frequency distributions and the overall summative DISCERN score for each website were calculated.Results The overall mean DISCERN score was 42.9 (SD = 9.4). The quality of information was only rated as good-excellent for 16% of websites and only 11% of websites showed full compliance with GDC guidelines on ethical advertising. A link to the GDC/authority website (75%), the date when the website was last updated (72%), and the practice complaints policy (66%) were not commonly provided. The country of qualification, a statement of whether practices provide NHS or private treatment or a combination of both, and the date when the website was last updated, were significant predictors for the overall quality based on DISCERN score.Conclusions The quality of information provided on websites providing aligner therapy and their compliance with GDC guidelines on ethical advertising was suboptimal. An improvement in both areas is required.

Reporting of flow diagrams in randomised controlled trials published in periodontology and implantology: a survey.

BACKGROUND: Item 13 of the CONSORT guidelines recommends documentation of the participant flow in randomised clinical trials (RCTs) using a diagram. In the medical literature, the reporting of the flow of participants in RCTs has been assessed to be inadequate. The quality of reporting flow diagrams in periodontology and implantology remains unknown. The aim of this study was to assess the reporting of flow diagrams in RCTs published in periodontology and implantology journals. MATERIALS AND METHODS: RCTs published between 15th January 2018 and 15th January 2022 in twelve high-ranked periodontology and implantology journals were identified. Trial characteristics at the RCT level were extracted. The flow diagram included in each RCT was assessed for completeness of reporting in relation to published criteria and the CONSORT flow diagram template. RESULTS: From the 544 eligible articles, 85% were single-centre, 82% of parallel-group design and 79% investigated surgical interventions. Three-hundred and fifteen (58%) articles were published in CONSORT endorsing journals. A flow diagram was reported in 317 (58%) trials and reporting was more common in periodontology (73.1%). Overall, 56% of publications with a flow diagram reported a complete CONSORT flow diagram, while in 44% of flow diagrams, at least one point from the CONSORT reporting template was missing. Reasons for loss to follow-up (69.7%) and exclusions from the RCT analysis (86.4%) were poorly reported. CONCLUSION: The reporting of flow diagrams in periodontology and implantology RCTs was sub-optimal. Greater awareness of the importance of fully completing the participant CONSORT flow diagram is required.

Interventions to facilitate the successful eruption of impacted maxillary incisor teeth due to the presence of a supernumerary: A systematic review and meta-analysis.

INTRODUCTION: A failure of maxillary incisor eruption is commonly attributed to the presence of a supernumerary tooth. This systematic review aimed to assess the percentage of impacted maxillary incisors that successfully erupt after surgical removal of supernumerary teeth with or without other interventions. METHODS: Systematic literature searches without restrictions were undertaken in 8 databases for studies reporting any intervention aimed at facilitating incisor eruption, including surgical removal of the supernumerary alone or in conjunction with additional interventions published up to September 2022. After duplicate study selection, data extraction, and risk of bias assessment according to the risk of bias in nonrandomized studies of interventions and Newcastle-Ottawa scale, random-effects meta-analyses of aggregate data were conducted. RESULTS: Fifteen studies (14 retrospective and 1 prospective) were included with 1058 participants (68.9% male; mean age, 9.1 years). The pooled eruption prevalence for removal of the supernumerary tooth with space creation or removal of the supernumerary tooth with orthodontic traction was significantly higher at 82.4% (95% confidence interval [CI], 65.5-93.2) and 96.9% (95% CI, 83.8-99.9) respectively, compared with removal of an associated supernumerary only (57.6%; 95% CI, 47.8-67.0). The odds of successful eruption of an impacted maxillary incisor after removal of a supernumerary were more favorable if the obstruction was removed in the deciduous dentition (odds ratio [OR], 0.42; 95% CI, 0.20-0.90; P = 0.02); if the supernumeraries were conical (OR, 2.91; 95% CI, 1.98-4.28; P <0.001); if the incisor was in the correct position (OR, 2.19; 95% CI, 1.14-4.20; P = 0.02), at the level of the gingival third (OR 0.07; 95% CI, <0.01-0.97; P = 0.04) and had incomplete root formation (OR, 9.02; 95% CI, 2.04-39.78; P = 0.004). Delaying removal of the supernumerary tooth 12 months after the expected eruption time of the maxillary incisor (OR, 0.33; 95% CI, 0.10-1.03; P = 0.05) and waiting >6 months for spontaneous eruption after removal of the obstacle (OR, 0.13; 95% CI, 0.03-0.50; P = 0.003) was associated with worse odds for eruption. CONCLUSIONS: Limited evidence indicated that the adjunctive use of orthodontic measures and removal of supernumerary teeth might be associated with greater odds of successfull impacted incisor eruption than removal of the supernumerary tooth alone. Certain characteristics related to supernumerary type and the position or developmental stage of the incisor may also influence successful eruption after removal of the supernumerary. However, these findings should be viewed with caution as our certainty is very low to low because of bias and heterogeneity. Further well-conducted and reported studies are required. The results of this systematic review have been used to inform and justify the iMAC Trial.

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.

The prevalence of and factors influencing statistical testing of baseline characteristics in randomized controlled trials published in high-impact orthodontic journals.

INTRODUCTION: When proper randomization has been undertaken, statistical testing of baseline characteristics between participants in trial arms in randomized controlled trials (RCTs) is not required. This investigation aimed to assess the prevalence of statistical testing of baseline differences in orthodontic RCTs. Factors influencing the undertaking of this analysis were explored. METHODS: Orthodontic RCTs published between January 1, 2017 and December 31, 2021 in 5 orthodontic journals were identified. To determine if statistical testing of baseline differences had been undertaken, each article was reviewed in detail to identify the reporting of P values and the term "significant difference" in the table of characteristics, the table legends, and the results section of each included RCT. Trial characteristics at the RCT level were extracted. Frequency distributions were calculated for the included trial characteristics. Significant predictors from the univariate analysis were used to construct a multivariable Bayesian logistic regression model. RESULTS: One hundred and thirty-two RCTs were analyzed. Significance testing of baseline characteristics was undertaken in 50% (66/132) of RCTs. At a journal level, significance testing at baseline was infrequently undertaken in RCTs published in the American Journal of Orthodontics and Dentofacial Orthopedics (AJODO). Compared with 2017, RCTs published in 2018 (odds ratio [OR], 5.57; 95% credible interval [CrI], 1.33-25.69), 2019 (OR, 17.82; 95% CrI, 4.41-82.11), 2020 (OR, 6.48; 95% CrI, 1.72-27.12), and 2021 (OR, 3.24, 95% CrI, 0.81-14.01) had higher odds of significance testing at baseline. RCTs published in the European Journal of Orthodontics (OR, 5.31; 95% CrI, 1.79-17.04), Progress in Orthodontics (OR, 5.00; 95% CrI, 0.97-28.43), Orthodontics and Craniofacial Research (OR, 6.49; 95% CrI, 1.04-46.10), and Angle Orthodontist (OR, 12.30; 95% CrI, 3.27-51.44) had higher odds of significant testing at baseline testing compared with AJODO. CONCLUSIONS: Statistical testing of baseline differences is common in orthodontic RCTs. Trials published in AJODO had the lowest incidence of statistical testing of baseline differences. RCTs published between 2018-2021 had higher odds of significance testing at baseline than in 2017. Per the consolidated standards of reporting trials guidelines, this practice should be discouraged as it can be misleading and unnecessary.

Studies with statistically significant effect estimates are more frequently published compared to non-significant estimates in oral health journals.

BACKGROUND: Studies reporting statistically significant effect estimates tend to be more frequently published compared to studies reporting non-significant or equivalent estimates. Consequently, this may lead to distortion of the literature. The aim of this study is to assess the prevalence of reporting statistically significant effect estimates in leading oral health journals and to explore associations between the effect estimates and record characteristics. METHODS: An electronic database search was undertaken of a selection of leading oral health journals including general oral health journals to identify primary oral health records published in 2019. Descriptive statistics and population average GEE logistic regression model was used to assess associations between articles reporting a statistically significant effect estimate and the record characteristics. RESULTS: In 1335 records, 82.4% records reported a statistically significant effect estimate. All speciality journals compared to general oral health journals were less likely to publish a record with significant effect estimates. Authors based in Asia or other (OR 1.49; 95% CI :1.02,2.19; p = 0.037) were more likely to report significant effect estimates compared to those based in Europe. Interventional (OR 0.35; 0.22,0.58; p < 0.001) and observational (OR 0.56; 0.36, 0.89; p = 0.013) records were less likely to report significant effect estimates compared to in-vitro studies. Registered records were less likely to report significant effect estimates when compared to non-registered studies (OR 0.22; 95% CI :0.14,0.32; p < 0.001). CONCLUSION: The publishing of records with significant effect estimates is prevalent within the oral health literature. To reduce dissemination bias and overestimation of effect sizes in systematic reviews, the publishing of studies with non-significant or equivalent effect estimates should be encouraged.

Orthodontic clinicians' attitudes and knowledge of dentogingival aesthetics: A cross-sectional survey of BOS members.

OBJECTIVE: To assess orthodontic clinicians' knowledge and attitudes towards dentogingival aesthetics and to explore characteristics that predict the knowledge of dentogingival aesthetics. DESIGN: Cross-sectional questionnaire. SETTING: On-line survey of members of the British Orthdontic Society. MATERIALS AND METHODS: An 11-item online questionnaire was sent to orthodontic practitioners for completion. The questionnaire covered respondent demographics and questions relating to both knowledge and attitudes towards dentogingival aesthetics (six parameters). Descriptive statistics were calculated for study characteristics and summary values for the survey items. Responses to the eight knowledge-based questions were converted to a binary outcome (correct and incorrect answer). The maximum score that could be achieved was eight. Multivariable modelling was used in order to examine associations between the study characteristics and the aggregate score. RESULTS: A total of 252 responses were obtained resulting in a response rate of 17%. Within this cohort, the respondents were primarily women (52.8%) and aged 30-40 years (35.7%). The mean score for the eight knowledge-based questions was 3.8 ± 1.8 (range = 0-8). Knowledge of the ideal gingival margin position of the anterior teeth was high (92.4%). Knowledge of the other five dentogingival aesthetic parameters was variable. In the multivariable analysis, lower knowledge scores were predicated by respondents who did not have a special interest in dental aesthetics (-0.54; 95% confidence interval [CI] = -1.01 to -0.07; P = 0.02), who could not recall attending courses, lectures or seminars on dental aesthetics in the past five years (-0.80; 95% CI = -1.43 to -0.17; P = 0.01) and with increasing age (-0.43; 95% CI = -0.62 to -0.23; P < 0.001). CONCLUSION: Knowledge of ideal dentogingival parameters is generally suboptimal among orthodontists in the UK. The reported lack of knowledge of the ideal dentogingival parameters may also influence respondents' attitudes towards the importance of dentogingival aesthetics. Further teaching or courses related to dentogingival aesthetics is desired by orthodontic clinicians.

Survival of conventionally bonded mandibular retainers with or without enamel sandblasting in orthodontic patients over a 12-month period. A single-centre, split-mouth randomized clinical trial.

BACKGROUND: The aim of this trial was to assess the effect of enamel sandblasting in addition to the acid-etch technique in reducing first-time failures of fixed mandibular retainers placed over a 12-month period. MATERIALS AND METHODS: Ethical approval was obtained. Participants were recruited in a single private practice. The primary outcome of this study was any first-time failure of the mandibular fixed retainer assessed at three timepoints over a 12-month period. Three consecutive teeth either on the left or right side (from lower canine-lower central incisor) were randomly allocated to the intervention (sandblasting) and the control (non-sandblasted). Randomization was performed using a centralized randomization service. The patients were randomized in blocks of four and eight with allocation concealment secured by contacting the sequence generator for group assignment. Blinding of either the patient or clinicians was not possible at time of placement of the mandibular retainer. RESULTS: One hundred and ninety-seven participants were randomized to receive enamel sandblasting (intervention) and non-sandblasting (control) in the region of the six anterior mandibular teeth in a split-mouth fashion. Participants were recruited between December 2018 to October 2020. The data for all participants were analysed resulting in 394 observations. Overall, the risk of first-time failure was 11.4%. No difference in first-time failures was observed between the intervention (sandblasting) and control (non-sandblasting) groups [hazard ratio (HR), 1.05; 95% confidence interval (CI), 0.59, 1.88, P = 0.88]. Males had a higher instant probability of first-time failures (HR, 3.18; 95% CI, 1.65-6.14; P < 0.01). Participants with a fair level of co-operation had a lower instant probability of first-time failures (HR, 0.37; 95% CI, 0.16-0.86; P = 0.02). There were no harms reported to either the participant or their dentition. CONCLUSIONS: No difference in the first-time failures of mandibular bonded retainers placed with conventional etch-bond technique with or without enamel sandblasting was observed. The overall risk of first-time failure was 11.4%. REGISTRATION: This trial was not registered prior to trial commencement.

Not enough SPIRIT shown in the registration and reporting of orthodontic trial protocols.

BACKGROUND: To reduce bias associated with selective reporting, the registration and publication of clinical trial protocols before or at the time of patient enrolment has been advocated. The aim of this investigation was to assess the frequency of registration and reporting adherence of orthodontic trial protocols pre- and post-introduction of the Standard Protocol Items Recommendations for Interventional Trials (SPIRIT) Statement. MATERIALS AND METHOD: Trial protocols registered in four online registries were sourced at two time periods: (1 January 2010-1 January 2013) and (1 January 2017-1 January 2021). Protocols were screened and data extracted, in duplicate and independently. The reporting adherence of each protocol was assessed in relation to the thirty-three item SPIRIT statement. Fisher's exact test was used to determine associations between time periods and trial protocol characteristics. Median regression was implemented to assess potential associations between the percent score per protocol and protocol characteristics. RESULTS: A total of 100 protocols were analysed. Thirty-three and sixty-seven protocols were registered in the first and second time periods, respectively. An association between period and the timing of registration (prospectively or retrospectively) (P < 0.001) and funding source (University or Company) (P < 0.001) was evident. Overall, 25 of the 33 (75.5%) SPIRIT statement items were not reported in either timeframe. The median percent reporting quality score was 26.9 (IQR 6.9). The type of registry was associated with percent scores and published studies received better percent scores compared to unpublished studies and academic or private protocol submissions. CONCLUSIONS: There is a general lack of awareness of the importance and relevance of the SPIRIT statement. Registration of orthodontic trial protocols has apparently improved; however, 75.5% SPIRIT statement items were not reported in either study time period. The registration and reporting of orthodontic trial protocols should be advocated to circumvent issues relating to selective reporting and outcome reporting bias.

Accounting for clustering is still not routinely undertaken in orthodontic studies.

BACKGROUND: The aim of this study was to identify studies with clustering effects published in orthodontic journals and to assess the frequency by which clustered designs are correctly accounted for in the statistical analysis. Factors associated with appropriate management of clustering effects during the statistical analysis were explored. MATERIALS AND METHOD: A search of three leading orthodontic journals was undertaken to identify studies with clustering effects published between 1 January 2019 and 31 December 2021. Descriptive statistics and frequency distributions were calculated. Associations between the correct statistical handling of clustering effects and study characteristics were explored via univariable and multivariable analyses. RESULTS: Three hundred and sixty-two studies were considered to have clustering effects. Only 22.4 per cent of studies correctly accounted for clustering effects in the statistical analysis with no improvement compared to a previous study in 2012 using the same journals. An association between the use of the correct analysis to account for clustering and the following study characteristics was detected: involvement of statistician, study type, significance of the results, and accounting for clustering in the sample size calculations. In the univariable analysis, interventional studies, non-significant results, and the involvement of a statistician were associated with higher odds of the use of the correct analysis. Of the studies correctly accounting for clustering, the most used tests were repeated measures ANOVA (43.3 per cent) and mixed models (40.7 per cent). CONCLUSIONS: Compared to previous research, there appears to be no improvement in accounting for clustering effects in studies published in orthodontic journals. To prevent incorrect inferences being drawn, clustering effects need to be recognised and accounted for in orthodontic studies. Recommendations to improve the accounting of clustering effects, at both the study level and during the statistical analysis are suggested.

The reporting adherence of observational studies published in orthodontic journals in relation to STROBE guidelines: a meta-epidemiological assessment.

BACKGROUND: To facilitate clear and transparent reporting of observational studies the STROBE guidelines were developed. The aim of this investigation was to assess the reporting adherence of observational studies published in orthodontic journals in relation to STROBE guidelines. Associations between the reporting quality and study characteristics were explored. MATERIALS AND METHOD: A search of five leading orthodontic journals was undertaken to identify observational studies published between 1st January 2021 and 31st June 2021. Data extraction was performed in duplicate and independently. Descriptive statistics and frequency distributions for the responses to each checklist item were calculated. Proportional odds ordinal logistic regression for clustered data was implemented to assess potential associations between the three-level categorical outcome (not reported, inadequate reporting, adequate reporting) and study characteristics and individual checklist items. RESULTS: One hundred and thirty-five studies were analysed. The majority of studies were cohort designs (54.0%). Variability in the reporting of the STROBE guideline items was evident. In particular, a clear description of outcomes, exposures, predictors, potential confounders, and effect modifiers, statistical methods and participants were inadequately reported. In the multivariable analysis, the overall score test indicated that only item was a significant predictor of reporting quality (P < 0.001). CONCLUSIONS: The findings of this study have highlighted that the reporting of observational studies published in orthodontic journals in relation to the STROBE guidelines is sub-optimal. Key areas of inadequate reporting relate to methodology and results. Key determinant of reporting quality was the STROBE item.

Duration of canine retraction with fixed appliances: A systematic review and meta-analysis.

INTRODUCTION: Space closure is a challenging and time-consuming phase of orthodontic treatment with fixed appliances. This systematic review evaluated canine retraction duration using fixed appliances after maxillary first premolar extraction. METHODS: Unrestricted systematic literature searches were conducted in 8 databases for randomized clinical trials, assessing the duration and rate of maxillary canine retraction using fixed appliances with or without treatment adjuncts published up to July 2021. Study selection, data extraction, and risk of bias evaluation were conducted independently and in duplicate. Random-effects meta-analyses of average rates or mean differences (MD) and 95% confidence intervals (CI) were conducted at α = 5%, followed by sensitivity and Grading of Recommendations Assessment, Development, and Evaluation analysis. RESULTS: Fifty randomized clinical trials (6 parallel and 44 split-mouth designs) covering 811 participants (mean age 19.9 years; 34% male) were included. The estimated average pooled duration to achieve complete canine retraction was 4.98 months (2 trials; 95% CI, -2.9 to 12.88 months). Pooled average canine retraction was 0.97 mm at months 0-1 (23 trials; 95% CI, 0.79-1.16), 1.83 mm at months 0-2 (20 trials; 95% CI, 1.52-2.14), 2.44 mm at months 0-3 (23 trials; 95% CI, 2.10-2.79), 3.49 mm at months 0-4 (6 trials; 95% CI, 1.81-5.17) and 4.25 mm at months 0-5 (2 trials; 95% CI, 0.36-8.14). Surgically-assisted orthodontics was associated with greater canine retraction at all time points: months 0-1 (10 trials; MD, 0.52 mm; P = 0.004), months 0-2 (8 trials; MD, 0.53 mm; P = 0.04), months 0-3 (8 trials; MD, 0.67 mm; P = 0.01), and months 0-4 (3 trials; MD, 1.13 mm; P = 0.01), whereas subgroup analyses indicated significant effects of anchorage reinforcement method and bracket slot size on canine retraction. CONCLUSIONS: The average time to achieve complete retraction of the maxillary canine using fixed appliances was around 5.0 months. Most studies used split-mouth randomization to investigate canine retraction for around 1-3 months, with substantial heterogeneity across studies. At 3 months of treatment, high-quality evidence supported greater canine retraction with surgically-assisted orthodontics.