Orthodontic retention: Rationale and periodontal implications.

Post-treatment change in the form of true relapse and physiological and maturational effects is common following orthodontics. The unpredictable nature of these manifestations dictates a conservative, near-universal approach to retention. Both fixed and removable forms of retention are popular with the latter constrained by variable levels of adherence particularly in the medium- to long-term. Fixed retention may offer a more predictable means of preservation of orthodontic outcomes; however, this advantage is offset by the requirement for prolonged supervision and the potential for adverse changes including periodontal breakdown. Nevertheless, while examples of severe complications are common, a clear causal relationship between intact, passive retainers and periodontal issues does not appear to exist. Nevertheless, the importance of diligent maintenance and careful supervision during fixed retention, in particular, cannot be disregarded.

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.

Mandibular second molar extraction: A retrospective cohort study of spontaneous occlusal changes in adolescent patients.

OBJECTIVES: Evaluate long-term spontaneous occlusal changes following L7 extraction in adolescent patients. MATERIALS AND METHODS: Study models of 144 participants (63 males, 81 females) retrospectively assessed prior to L7 extraction (9-16 years old; T1) and following L8 eruption (14-25 years old; T2). All received upper fixed appliances. A sub-group (n = 86) received no lower fixed appliances and acted as controls. Occlusal changes were compared between treatment (lower fixed appliance) and control (no lower fixed appliance) groups using PAR index. At T2, L8 occlusal outcome was assessed using ABO grading system. RESULTS: Mean follow-up period 6 (SD 2) years. At T1, lower scores observed in control group for Lower Anterior (P < .001), Midline (P = .033) and Lateral Segments (P = .040) components. At T2, lower scores continued being observed in control group for Midline (P < .001) and Lateral segment (P = .019) components. Higher decrease in Lower Anterior PAR scores observed in treatment group (<.001) with comparable scores between groups at T2 (P = .057). Similar PAR score changes between groups for Lateral Segments, Overjet and Overbite components. At T2, no significant difference observed in Total PAR score reduction between control (83%) and treatment (82%) groups. Good-to-acceptable occlusal outcome of the L8 observed in 81.55% of cases at T2 with no difference between groups. CONCLUSION: In growing patients with mild mandibular crowding, extraction of L7 followed by upper fixed appliance therapy, leads to favourable occlusal changes over a 6-year follow-up period, with or without lower fixed appliance therapy, being an alternative extraction protocol where lower fixed appliance therapy is not recommended.

Assessment of wear characteristics, longevity and stiffness of Essix-type retainers.

OBJECTIVE: To compare four commercially available Essix-type retainers in terms of longevity, wear characteristics, stiffness and their range of rigidity. MATERIALS AND METHODS: An in vitro study was conducted at Queen Mary University of London. Four groups of thermoplastic materials were included: Duran (PETG), Essix C + (Polypropylene), Vivera and Zendura (Polyurethane). A working typodont was fabricated to evaluate surface wear characteristics using a wear machine with a customized jig. Retainers were measured for tensile test, and water absorption was measured at five different time points up to 6 months after initial immersion in two different physical states and two different solutions. Hydrolytic degradation was also evaluated using FTIR spectroscopy. RESULTS: Essix C + was the most flexible retainer with Vivera the stiffest material. Zendura and Essix C + had the most surface wear (413 µm ± 80 and 652 µm ± 12, respectively) with absorption rates of up to 15 wt% in artificial saliva occurring with Zendura. Only Essix C + displayed signs of degradation following water absorption. CONCLUSIONS: All materials had characteristic levels of flexibility and were susceptible to water absorption. Duran 1.5 mm performed similarly to Vivera in relation to stiffness and wear properties. While Zendura and Vivera have similar chemical structures, they exhibited differences concerning wear resistance and water absorption. Further clinical research evaluating the clinical relevance of these laboratory findings is required. CLINICAL RELEVANCE: Characteristic patterns of wear and rigidity of four commercially available Essix-type retainers were observed. This information should help in the tailoring of retainer material on a case-by-case basis considering treatment-related factors and patient characteristics including parafunctional habits.

Repeated local delivery of hyaluronic acid gel as adjunctive treatment of residual pockets in periodontitis patients undergoing supportive periodontal care. A randomized controlled clinical trial.

OBJECTIVES: To assess the effect of hyaluronic acid (HyA) application as adjunct to re-instrumentation of residual pockets in patients undergoing regular supportive periodontal care (SPC). METHODS: Chronic periodontitis patients (stage III and IV, grade B and C) with 4 interproximal residual pockets were randomly assigned to the test (HyA gel) or control (saline) group. After subgingival instrumentation, test or control substance was applied subgingivally, then daily supragingivally for 3 months, and if required a second time after subgingival re-instrumentation after 3 months. Clinical and patient reported outcome parameters were recorded every 3 months for 12 months. Pocket closure [probing pocket depth (PPD) ≤ 4mm with absence of bleeding on probing (BoP) at PPD = 4mm] was the main outcome parameter. RESULTS: Fifty-six patients (221 experimental sites) were analysed. Pocket closure was achieved in 56.8 and 46.6% of the experimental sites in the test and control group, respectively (p > 0.05), while median PPD and PPD distribution (< 5mm/5mm/ > 5mm) differed significantly between groups in favour of the test group, at 12 months. Further, significantly fewer sites in the HyA group required re-instrumentation at 3 months, and sites in the HyA group showed a tendency for lower odds to remain diseased compared to the control group (OR 0.48, 95%CI 0.22-1.06). The odds for a site to remain diseased after 12 months increased significantly in the presence of plaque (OR 7.94, 95%CI 4.12-15.28), but in general, decreased significantly over time (OR 0.48, 95%CI 0.28-0.81). CONCLUSION: Re-instrumentation of residual pockets in SPC patients, per se, leads to a significant increase in pocket closure over time; this was impeded by poor plaque control. Repeated local application of HyA results in fewer sites requiring re-instrumentation and might slightly improve the rate of pocket closure. (clinicaltrials.gov registration nr. NCT04792541). CLINICAL RELEVANCE: HyA gel is easy to apply, well accepted by patients, and may have some positive effect in terms of fewer sites requiring re-instrumentation at 3 months and higher pocket closure rate at 12 months.

Midpalatal miniscrew insertion: The accuracy of digital planning and surgical placement.

INTRODUCTION: The objective of this study was to investigate the accuracy of palatal miniscrew insertion, evaluating the effect of guide fabrication and surgical placement. METHODS: Guided insertion of bilateral paramedian palatal miniscrews was undertaken using Appliance Designer software (3Shape, Copenhagen, Denmark). A resin surgical guide (P Pro Surgical Guide; Straumann AG, Basel, Switzerland) was used. Superimposition of the miniscrew position relative to the digital design was undertaken using bespoke software (Inspect 3D module, OnyxCeph; Image Instruments GmbH, Chemnitz, Germany) to assess surgical inaccuracy. Miniscrew position relative to the surgical guide was also assessed to isolate the effect of planning inaccuracies. Both horizontal and vertical discrepancies were evaluated at both implant locations. RESULTS: Twenty-seven patients having bilateral palatal insertions were examined. Mean discrepancies were <0.5 mm, both in the horizontal and vertical planes. The mean overall horizontal and vertical discrepancy between the digital design and final miniscrew position on the left side was 0.32 ± 0.15 mm and 0.34 ± 0.17 mm, respectively. The maximum horizontal discrepancy observed was 0.72 mm. No significant differences were observed in relation to the accuracy of mini-implant positioning on the basis of sidedness, either for horizontal (P = 0.29) or vertical (P = 0.86) discrepancy. CONCLUSIONS: High levels of accuracy associated with guided insertion of paramedian palatal implants were recorded with mean discrepancies of less than 0.5 mm both in the horizontal and vertical planes. No difference in accuracy was noted between the left and right sides. Very minor levels of inaccuracy associated both with surgical techniques and surgical guide fabrication were recorded.

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.

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.

Health-related quality of life aspects of the 'Periodontitis prevalence in ulcerative colitis and Crohn's disease' (PPCC) cohort.

AIM: To assess whether oral health problems affect disease-specific quality of life (QoL) of inflammatory bowel disease (IBD) patients, and vice versa, whether IBD affects oral-health-related QoL. MATERIALS AND METHODS: Individuals reporting IBD and matched controls were surveyed on general anamnestic information, oral-health-related questions and the Oral Health Impact Profile (OHIP)-5. IBD patients were additionally surveyed on years since diagnosis, disease activity and severity as well as health-related QoL (Short Inflammatory Bowel Disease Questionnaire, sIBDQ). OHIP-5 and sIBDQ were defined as primary outcome parameters, and several predictors and confounders were used in adjusted univariable and multivariable regression analyses. RESULTS: Answers from 1108 IBD patients and 3429 controls were analysed. Compared with controls, IBD patients reported significantly more frequently an oral impact on daily life and worse oral-health-related QoL, with Crohn's disease (CD) patients being more severely affected than ulcerative colitis (UC) patients. The diagnosis of UC and CD, having <20 teeth, severe periodontitis and stressful daily-life experience were associated with a higher prevalence of poor oral-health-related QoL. Among IBD patients, an impaired IBD-specific, health-related QoL was significantly associated with the diagnosis of CD and depression, IBD activity and severity, having <20 teeth, presence of oral lesions and stressful daily-life experience, while a longer time since diagnosis was significantly associated with an improved IBD-specific, health-related QoL. CONCLUSIONS: The results of the present study indicate, for the first time, that oral health problems are associated with an impairment of IBD-specific health-related QoL, and vice versa, IBD is associated with an impaired oral health-related QoL. This emphasizes the potential advantages of including dental professionals in the multi-disciplinary treatment teams of IBD patients.

Hyaluronic acid in tooth extraction: a systematic review and meta-analysis of preclinical and clinical trials.

OBJECTIVES: To assess whether in animals or patients with ≥ 1 tooth extracted, hyaluronic acid (HyA) application results in superior healing and/or improved complication management compared to any other treatment or no treatment. MATERIALS AND METHODS: Three databases were searched until April 2022. The most relevant eligibility criteria were (1) local application of HyA as adjunct to tooth extraction or as treatment of alveolar osteitis, and (2) reporting of clinical, radiographic, histological, or patient-reported data. New bone formation and/or quality were considered main outcome parameters in preclinical studies, while pain, swelling, and trismus were defined as main outcome parameters in clinical studies. RESULTS: Five preclinical and 22 clinical studies (1062 patients at final evaluation) were included. In preclinical trials, HyA was applied into the extraction socket. Although a positive effect of HyA was seen in all individual studies on bone formation, this effect was not confirmed by meta-analysis. In clinical studies, HyA was applied into the extraction socket or used as spray or mouthwash. HyA application after non-surgical extraction of normally erupted teeth may have a positive effect on soft tissue healing. Based on meta-analyses, HyA application after surgical removal of lower third molars (LM3) resulted in significant reduction in pain perception 7 days postoperatively compared to either no additional wound manipulation or the application of a placebo/carrier. Early post-operative pain, trismus, and extent of swelling were unaffected. CONCLUSIONS: HyA application may have a positive effect in pain reduction after LM3 removal, but not after extraction of normally erupted teeth. CLINICAL RELEVANCE: HyA application may have a positive effect in pain reduction after surgical LM3 removal, but it does not seem to have any impact on other complications or after extraction of normally erupted teeth. Furthermore, it seems not to reduce post-extraction alveolar ridge modeling, even though preclinical studies show enhanced bone formation.

Dietary and metabolic effects on the oral status of patients with phenylketonuria: a nation-based cross-sectional study.

OBJECTIVES: The aim of this study was to compare the prevalence of oral diseases (caries, periodontal disease, enamel defects) between patients with phenylketonuria (PKU), their siblings, and a matched control group. MATERIALS AND METHODS: A total of 109 patients with PKU, 14 siblings of PKU patients, and 100 healthy individuals aged 6 to 68 years were recruited. All participants completed a questionnaire based on their health status. The patients' decayed/missing/filled teeth index (dmft/DMFT), gingival bleeding index (GBI), plaque control record (PCR), periodontal screening and recording index (PSR), and developmental enamel defects index (DDE) were recorded. Descriptive statistics and regression modeling were used to examine potential associations between the exposure and the outcomes of interest. RESULTS: Patients with PKU had 1.6 times more caries (95% confidence interval (CI) 1.22 to 2.20; p = 0.001), seven times more enamel defects (95% CI 3.94 to 14.21; p < 0.001), and four times higher PSR values (95% CI 2.26 to 7.15; p < 0.001) than the control group. The siblings had significantly fewer enamel defects but no significant differences in caries and periodontal parameters compared to the PKU patients. CONCLUSIONS: The results showed a higher risk for the development of caries, periodontitis, and enamel defects in PKU patients. CLINICAL RELEVANCE: Implementation of preventive measures and regular dental care is necessary for patients with PKU.

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.

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.

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.

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.

The effect of mastic mouthwash on halitosis and oral hygiene in orthodontic patients: a randomized clinical trial.

BACKGROUND/OBJECTIVES: The aim of this trial was to investigate the effect of mastic mouthwash on halitosis using as a proxy the levels of the Volatile Sulfur Compounds (VSCs), and the effect on plaque and gingival indices in adolescents undergoing orthodontic treatment with fixed conventional labial appliances. SUBJECTS/METHODS: The study was a double-blinded, placebo-controlled, parallel-group, randomized clinical trial. Thirty patients with fixed orthodontic appliances were randomly allocated at a 1:1 ratio, to either the mastic-mouthwash or the placebo-mouthwash group. Eligibility criteria included ages between 13 and 18, active orthodontic treatment with fixed appliances, good general health, and total initial VSCs levels above 150 ppb. The primary outcome was the objective hydrogen sulfide (H2S) level, measured with the Oral ChromaTM device. The secondary outcomes were (1.) the methyl-mercaptan (CH3SH) and (2.) dimethyl sulfide [(CH3)2S] levels, measured with the same device, (3.) the subjective perception of the own malodour via questionnaires, and (4.) the oral hygiene assessed with the use of the Modified Silness and Löe Plaque Index (PI-M) and the Silness and Löe Gingival Index (GI) at baseline (T0) and after 2 weeks (T1). Stratified randomization by gender was used, and allocation was concealed with opaque numbered sealed envelopes. RESULTS: H2S level dropped from 221.00 ppb (T0) to 125.00 ppb (T1), and the difference between treatment groups was statistically significant in favour of the mastic group (coef: 72.34, 95% CI: 8.48, 136.27, P = 0.03). The levels of the other VSCs, the subjective measurements of oral malodour, and the oral hygiene indices did not differ between treatment arms. LIMITATIONS: The objective organoleptic assessment by a calibrated examiner was not performed. CONCLUSIONS/IMPLICATIONS: Mastic mouthwashes could be an alternative treatment for adolescent patients suffering from halitosis during orthodontic treatment with fixed appliances. REGISTRATION: The trial was registered at ClinicalTrials.gov (identifier: NCT05647369).

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.

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.

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.

Public interest in Invisalign in developed and developing countries: A Google Trends analysis.

OBJECTIVE: To investigate long-term changes and possible seasonal variations in Google search volumes related to Invisalign in developed and developing countries. DESIGN: Cross-sectional, Google search-based study. METHODS: Google Trends (GT) was accessed to retrieve the Relative Search Volume (RSV) of Google queries related to the search term 'Invisalign' in 10 countries selected on the basis of population size, Internet usage and socioeconomic criteria between 1 January 2004 and 30 June 2021. The countries examined were the following: Australia, Brazil, Italy, Mexico, Philippines, Saudi Arabia, Spain, Thailand, UK and USA. By applying the time series decomposition method, the trend component and the seasonal variation were identified. RESULTS: Overall, RSVs regarding Invisalign have increased significantly in all countries with the developed countries outperforming developing countries throughout most of the observation period. There was no meaningful pattern when the trends were compared either on a monthly or quarterly basis. Similar peaks and valleys were found in Australia - Brazil, UK - USA, Italy - Spain and Saudi Arabia - Philippines - Thailand. CONCLUSIONS: Public interest in online information for Invisalign has grown significantly over the years across countries of diverse socioeconomic and cultural backgrounds while seasonal patterns were observed in the related Google searches. Seasonal fluctuations seemed to follow the academic calendar. The study results may have direct implications on practice management and professional development.