European journal of orthodontics最新文献

Objectives: To examine the effects of orthodontic treatment with fixed appliances on masseter muscle thickness in growing children.

Subjects and method: Forty children with a mean pre-treatment age of 12.9 ± 1.19 years with mild to moderate malocclusions were treated with fixed appliances. Forty untreated children served as the control group, with a mean age of 9.14 ± 0.91 years at the start of the study. Masseter muscle thickness was measured by ultrasonography at treatment start and 1 year later in the patient group, and at equivalent times in the control group. Differences within and between the groups were evaluated using paired and independent sample t-tests, respectively. Multiple regression analysis was conducted to examine associations between different variables, including age, gender, and treatment.

Results: Masseter thickness at the beginning of the study was smaller (P = .004) in the control group (10.57 ± 1.04 mm) than in the treatment group (11.26 ± 1.03 mm), an observation that can be partly explained by the initial age difference between the groups. One year later, masseter muscle thickness increased in the control group (0.38 ± 0.50 mm, P < .001) while no statistically significant changes were found in the treatment group (-0.08 ± 0.55 mm, P = .37). The observed change in masseter muscle thickness in the two groups presented statistically significant differences (0.46 ± 0.11 mm, P < .001).

Conclusions: Masseter muscles in growing children normally increase in thickness annually. Fixed appliance treatment seems to hinder this growth during a 1-year treatment period. This information should be considered when assessing the progress and stability of the orthodontic treatment of certain malocclusions.

Aim: To investigate whether the functional capacity of elevator masticatory muscles, estimated by masseter muscle thickness, is associated with malocclusions in the sagittal, vertical, and transverse axes.

Materials and methods: 670 consecutive cases were evaluated. Pre-treatment dental casts were examined for malocclusion characteristics (overjet, sagittal molar relationships, overbite, posterior crossbite), and ultrasonographic measurements of the masseter muscles were used for thickness measurements. Gender, age, and BMI were also recorded. A multiple linear regression analysis was conducted to investigate the association of masseter thickness with age, gender, BMI, and malocclusions. A subgroup analysis across age groups explored whether age and gender had a different impact on their association with masseter muscle thickness, and a paired t-test examined possible asymmetry in masseter muscle thickness between the crossbite and non-crossbite sides.

Results: Males showed thicker masseter muscles than females by 0.8 mm. Older-growing individuals presented thicker muscles, with a 1-year age increase resulting in a 0.1 mm increase in mean thickness, and patients with increased values of BMI presented thicker muscles. A 1mm overbite increase was associated with 0.1mm thicker masseter muscle. Patients with unilateral posterior crossbite showed thinner muscles on their crossbite (11.15 mm) than the non-crossbite side (11.42 mm) with a mean difference of 0.27 mm (P = 0.002).

Conclusions: Masseter muscle thickness was greater in males, subjects with increased values of BMI, and older-growing individuals, showing age-related growth that plateaued in adulthood. Patients with deep bite had thicker muscles, while patients with unilateral posterior crossbite showed thinner muscles on their crossbite side than on the non-crossbite side.

Background: Cerebral palsy (CP) results from developmental abnormalities or brain lesions that impair movement, posture, and motor function, thereby affecting skeletal development, including craniofacial structures.

Objectives: This study aimed to evaluate occlusal characteristics in individuals with and without CP.

Search methods: This systematic review followed Meta-Analysis of Observational Studies in Epidemiology guidelines. A comprehensive search was conducted in Embase, PubMed, Web of Science, Ovid, and Scopus, with additional screening of Google Scholar and OpenGrey.

Selection criteria: Observational studies were included, and the risk of bias was assessed using Newcastle-Ottawa Scale.

Data collection and analysis: Meta-analyses were performed to estimate odds ratios (ORs) with 95% confidence intervals (CIs) and prediction intervals. The GRADE approach was used to evaluate the certainty of the evidence.

Results: Of the 584 records identified, 24 cross-sectional studies met the inclusion criteria. Risk-of-bias assessment revealed concerns related to exposure appraisal, nonrespondent characterization, and study comparability. The meta-analysis indicated that individuals with CP had a higher likelihood of Class II malocclusion (OR = 2.56, 95% CI: 1.49-4.38, k = 18) and open bite (OR = 4.27, 95% CI: 1.95-9.37, k = 9).

Conclusions: Individuals with CP are at increased risk of developing Class II malocclusion and open bite, possibly due to neuromuscular dysfunctions and extrinsic factors. Effective management requires a multidisciplinary approach that addresses both biological and behavioral determinants.

Registration: PROSPERO CRD42024551180.

Objectives: To evaluate the prevalence and manifestations of selective outcome reporting (SOR) among randomized controlled trials (RCTs) in leading orthodontic journals, and to explore factors that may be potentially related to the presence of SOR.

Methods: A manual search was conducted to identify eligible RCTs published in eight leading orthodontic journals between 2018 and 2024. Only RCTs with defined primary outcomes (POs) in both publications and corresponding registrations were included. Discrepancies between publications and registrations were compared with respect to the PO. Logistic regression analysis was performed to assess the association between study characteristics and the presence of SOR.

Results: A total of 139 eligible RCTs were included for analysis, of which 99 (71.2%) were retrospectively registered. SOR was identified in 70 (50.4%) RCTs. The most frequent type of SOR was the omission of registered PO in the corresponding publication (n = 27, 19.4%), followed by the downgrade of registered PO (n = 25, 18.0%) and the introduction of new PO in the publications (n = 23, 16.5%). According to the logistic regression analysis, the prevalence of SOR was significantly correlated with statistician involvement (OR: 0.349, 95% CI: 0.127-0.961, P = .042), and the number of POs reported in the registration (OR: 5.581, 95% CI: 2.126-14.647, P < .001).

Conclusion: The prevalence of SOR was high among RCTs in leading orthodontic journals. Clinicians, editors along with other stakeholders are expected to make joint efforts to address this issue and improve the transparent reporting of outcomes.

Background: Photodynamic therapy is an alternative to chlorhexidine and fluoride products in controlling oral health during fixed orthodontic treatment.

Objectives: The primary aim was to evaluate the influence of toluidine blue-based dye and 660 nm diode laser on the accumulation of supragingival plaque and its bacterial composition in subjects undergoing fixed orthodontic treatment. The secondary outcomes were bacterial composition of the subgingival plaque, the gingival index, and evaluation of white spot lesions (WSL).

Trial design: Four-arm parallel randomized controlled trial.

Methods: In this single-blind study, 48 orthodontic patients were randomly allocated to four groups: photodynamic therapy (PDT), 1% chlorhexidine (CHX) varnish, tricalcium phosphate (TCP) varnish containing 5% NaF, and negative control. The interventions were performed immediately after bonding (T0), 6 weeks (T1), and 12 weeks (T2) later. Plaque index, total bacteria count in the supragingival plaque, and the gingival index were determined at T0 (before bonding), T1, T2, and T3 (18 weeks). Quantitative PCR of the bacteria in the subgingival plaque and evaluation of the WSL on intraoral photographs were performed at T0 (before bonding) and T3.

Results: Forty participants were included in the analysis. At T2 and T3, in the PDT and CHX groups, a significantly lower plaque index was noted compared with the control group (T2: P = 0.002, P < 0.001; T3: P = 0.005, P < 0.001). The total bacteria count significantly decreased in the PDT, CHX, and TCP-5% NaF groups during the study period (P = 0.023, P < 0.001). PDT, CHX, and TCP-5% NaF did not significantly decrease the number of bacteria in the subgingival plaque compared with that in the control group. A significant decrease in gingival scores between T1 and T2 was noted in the PDT group (P = 0.016). No new WSLs were noticed in the PDT or CHX groups. The least number of advanced lesions was diagnosed in the PDT group. No harms were encountered.

Conclusion: The effects of PDT on oral health were mostly comparable to those produced by CHX and TCP-5% NaF varnish and significantly different from those observed in the control group.

Trial registration: ClinicalTrials.gov NCT06331442.

Background/objectives: Recently, advancements have been made in the application and development of artificial intelligence (AI) tools in dentistry. This study aims to assess the diagnostic accuracy of an AI-driven platform in identifying impacted teeth using panoramic radiographs.

Materials/methods: A total of four sets of 50 orthopantomograms were examined: one set featured impacted canines, another included impacted third molars, a third contained impacted incisors, premolars, and both first and second molars, and the final set had no impacted teeth. Two human observers and the Diagnocat™ 1.0 software independently evaluated the images. The level of agreement was measured using Cohen's Kappa, and calculations for sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), along with the corresponding 95% Confidence Intervals, were also conducted. The number of impacted teeth identified by both methods was compared using the Wilcoxon signed-rank test, and McNemar's tests were performed to identify any differences in the proportions of identified impacted teeth between the two methods. Analyses were carried out using IBM SPSS version 29.0.

Results: The evaluation of the AI software's diagnostic performance in recognizing impacted teeth compared with expert clinicians showed that Diagnocat performed exceptionally well in terms of specificity and positive predictive value (PPV), demonstrating a highly reliable identification of impacted teeth with no false positives. The sensitivity for identifying third molars was also good. However, there were significant limitations in sensitivity for other impacted teeth, suggesting that negative results might require further consideration. Cohen's Kappa indicated almost perfect agreement between Diagnocat™ and expert assessments for identifying impacted third molars, but only fair agreement for impacted canines and other teeth. Significant differences were observed in the average number and the proportions of impacted teeth detected by the two methods.

Limitations: Employing a retrospective design and convenience sampling may limit the study's generalizability and clinical relevance.

Conclusion: While the AI-based platform shows promise in detecting impacted third molars, it is still insufficient to replace human evaluation as the standard for assessing impacted teeth in panoramic radiographs.

Objectives: Short root anomaly (SRA) is a risk factor for root resorption, complicating orthodontic treatment. Familial occurrences of SRA suggest a genetic component in its pathogenesis; however, the specific gene responsible remains unidentified. This study aimed to identify the genes involved in the development of SRA using exome sequencing in Japanese individuals with SRA.

Methods: To identify the genes responsible for SRA in the Japanese population, we enrolled 433 patients and measured their root-to-crown (R/C) ratio of the maxillary central incisors using orthopantomograms to establish the phenotypic definition of SRA. Patients with teeth exhibiting R/C ratio measurements <-2 standard deviations (SD) were diagnosed as having an extreme SRA phenotype. Exome sequencing was conducted on 17 patients with extreme phenotypes, and the findings were validated through Sanger sequencing.

Results: The average R/C ratio of the maxillary central incisors <-2 SD was 0.87. We identified four missense variants in five cases within the protocadherin alpha (PCDHA) gene cluster, associated with calcium-dependent cell adhesion. The variants were as follows: PCDHA3 (c.79G>C, p.Gly27Arg), PCDHA6 (c.2279C>T, p.Ser760Phe), PCDHA9 (c.1490G>A, p.Arg497Gln), and PCDHA13 (c.1185C>A, p.Phe395Leu). Their pathogenicity was investigated via in silico analyses.

Limitations: Our study was a hospital-based study rather than a community-based one, and measurements of the maxillary central incisors were taken using orthopantomograms, which might have introduced bias.

Conclusions: Our findings suggest that the PCDHA gene cluster may be one of the genetic factors involved in the onset of SRA and that variants in this gene cluster could potentially affect tooth root development.

Background: The duration of fixed orthodontic appliance treatment is a major concern for both patients and clinicians. A lengthy treatment increases the likelihood of iatrogenic effects and burdens patient compliance.

Objectives: The primary aim of this review is to compare the duration of orthodontic treatment between 0.018-inch and 0.022-inch slot brackets. Furthermore, the quality of treatment, iatrogenic effects, and patient perception will be explored as secondary outcomes.

Search methods: An unrestricted comprehensive search was undertaken on six electronic databases updated up to May 2025. Moreover, ongoing and unpublished studies were searched on relevant sources. The reference lists of retrieved studies were screened for potential studies.

Selection criteria: Only randomized clinical trials (RCTs) and prospective non-randomized studies (NRS) with parallel-arm design were selected for inclusion.

Data collection and analysis: Study selection, bias assessment, and data extraction were performed independently by two reviewers, and inconsistencies were resolved by a third reviewer. Quantitative analyses were undertaken for comparable studies presented as a random-effects model along with its 95% confidence intervals (CI). Additional sensitivity and subgroup analyses were performed. The generated summary effect was evaluated using the GRADE approach.

Results: Twelve articles involving nine unique studies (six RCTs and three NRS: 832 patients) met the inclusion criteria. The total duration of treatment did not differ between the bracket slot systems (standardized mean difference: -0.23; 95% CI: -0.68 to 0.23; I2: 24%; 4 studies; low level of evidence). Qualitative analysis revealed no significant differences between the 0.018-inch and 0.022-inch slot brackets regarding the quality of treatment outcomes, iatrogenic treatment effects, or patient-related outcomes.

Limitations: Differences in reporting and clinical heterogeneity precluded meta-analysis for the secondary review outcomes.

Conclusions and implications: Within the limitations of this systematic review, there is some low-quality evidence suggesting that bracket slot size does not significantly impact orthodontic treatment in terms of duration, treatment outcomes, or patient-centred variables.

Registration: PROSPERO CRD42019121569.

Objective: This study evaluated the stability of anterior open bite (AOB) treatment with bonded spurs (BS) after 4 years of follow-up.

Methods: The BS group included 26 patients (9 male, 17 female) in the mixed dentition with Class I or Class II malocclusion and AOB, treated with BS for 1 year. Lateral cephalograms were taken at pretreatment (T1, 8.06 years), post-treatment (T2, 9.11 years) and 4-year post-treatment (T3, 13.3 years). The control group comprised 20 untreated subjects (7 male, 13 female) with AOB. The primary outcome was the overbite change. Interphase cephalometric comparisons in the BS group were performed with repeated measures ANOVA followed by Tukey or Friedman test (P < 0.05). Intergroup comparisons were performed with t-tests, Mann-Whitney, and Chi-square tests (P < 0.05). Multiple linear regression analysis evaluated the influence of initial AOB severity and facial growth pattern on long-term overbite changes.

Results: During the follow-up, the BS group showed a slightly increase in overbite (0.87 ± 1.17 mm). Two patients (7.69%) demonstrated relapse with negative overbite (mean: -2.75 mm) at T3. During treatment, the BS group showed greater overbite increase (4.53 ± 1.55 mm), incisor extrusion (2.72 1.25 mm), and lingual tip of upper (2.72 ± 1.25°) and lower incisors (-2.24±3.61°) compared to the control group. Neither initial AOB severity nor facial growth pattern significantly influenced long-term overbite changes (P = 0.831).

Limitation: Ethnic heterogeneity between the BS and control groups, and the use of a historical control group, which made randomization impossible. Another limitation is the absence of data on the etiological habits in the control group.

Conclusions: Bonded spurs are effective for anterior open bite treatment in the mixed dentition, providing a high rate of long-term stability (92.31%).