Clear aligner technique has been revolutionizing the paradigm of contemporary orthodontic practice. However, protraction of mandibular molars is deemed as one of the most challenging tooth movements with clear aligners. This study aimed to evaluate the clinical effectiveness of cantilever arms in protracting mandibular molars with clear aligners. A total of 37 orthodontic aligner patients requiring molar protraction (>4 mm) were enrolled in this prospective study. These participants were allocated into either the control group (N = 19) or the cantilever group (N = 18), resulting in 25 mandibular molars in the control group and 22 molars in the cantilever group. Superimposition of pre- and post-treatment data was performed based on cone-beam computed tomography and intraoral scanning. The differences between the predicted and achieved tooth movements (mesiodistal angulation, buccolingual inclination, and molar protraction distance) were compared. The discrepancies between the predicted and achieved tooth movements (DPA) were determined. Predicted and achieved tooth movements (mesiodistal angulation, buccolingual inclination and protraction distance) were significantly different for both groups (all P < 0.001), and DPAs of mesiodistal angulation (11.7 ± 4.5 vs. 19.9 ± 4.7; P < 0.0001), buccolingual inclination (21.0 ± 7.2 vs. 33.9 ± 8.9; P < 0.0001) and molar protraction distance (0.8 ± 0.4 vs. 3.6 ± 1.5; P < 0.0001) were significantly smaller in the cantilever group than in the control group. The predictability of molar protraction was significantly higher in the cantilever group (87%) than in the control group (43%) (P < 0.0001). Integrating the cantilever system into clear aligners can mitigate mesial and lingual tipping of mandibular molars and enhance the predictability of mandibular molar protraction.

Rapid maxillary expansion (RME) is a common orthopedic intervention in mixed dentition. Evaluating facial soft tissue changes is important to understand its functional and esthetic implications. To compare facial soft tissue changes following RME using the Expander with Differential Opening (EDO) and the Hyrax-type (HT). This single- center, two-arm parallel randomized clinical involved twenty-two patients aged 6-11 years with posterior crossbites, who were randomly assigned to two treatment groups. In the EDO group, anterior and posterior screws were activated ½ turn twice a day reaching 10.4 and 7.2 mm, respectively. In the HT group, conventional Hyrax was activated ½ turn twice daily until reaching 7.2 mm. Both appliances were maintained for 6 months. The primary outcome was the change in the nasal base width. Secondary outcomes included five additional facial measurements. Stereophotogrammetry was performed at pre-expansion (T1), immediately post-expansion (T2), and 6 months post-expansion (T3) for both treatment groups. Randomization used a computer-generated 1:1 allocation with sealed opaque envelopes. Although double blinding was not possible, image analyses were blinded to timepoints. Intergroup and interphase changes were analyzed using two-way ANOVA with repeated measures. The comparison of RME groups and the control group was performed using ANOVA and Tukey tests (P < 0.05). The EDO group consisted of 11 patients (3 males, 8 females), with a mean age of 9.45 years. The HT group included 11 patients (4 males, 7 females) with a mean age of 9.35 years. Both type of expanders increased the nasal base width, with no significant difference between groups. A partial relapse of nasal width was observed during retention in the EDO group. The EDO group showed an increase in intercanthal width after RME. Both expanders showed a similar increase in labial intercommissural width and facial heights after expansion, with stability in the retention period. Both expanders increased the nasal base width and the labial intercommissural width. The EDO showed a partial relapse of nasal base width during retention. Soft tissues changes after RME in children were negligible with both types of expanders. No harms were observed. This trial protocol was registered by the Brazilian Clinical Trials Registry (ReBEC) under the number: RBR-2pd4s4q.

To evaluate the scope and short-term outcomes of interceptive orthodontic treatment delivered by general dental practitioners (GDPs) under the supervision of specialist orthodontists within a publicly funded healthcare system. This retrospective cohort study included all patients aged ≤18 years who received publicly funded interceptive orthodontic treatment in Region Västra Götaland, Sweden, during 2020-2024; the pediatric population (0-18 years) was approximately 400 000. In total, 22 000 cases were identified from electronic records. Analyses focused on four appliances: Activator, Extraoral Traction, Quad Helix, and Removable Plate. Detailed outcome assessment was performed for all cases from year 2020 (n = 4400), with extraction of age, sex, treatment indication, treatment duration, number of visits, and appliance-specific outcomes. In total, 21 946 treatments were registered over 5 years. The most common appliances were Removable Plates (n = 10 511), Activators (n = 6455), Quad Helix (n = 3164), and Extraoral Traction (n = 1816). On average, 4389 interceptive treatments were delivered annually, accounting for nearly 100 000 visits. Treatments were typically initiated in the late mixed dentition (mean age, 10.2-11.2 years; range, 8-13 years), with equal gender distribution. Mean treatment duration ranged from 11 months (Quad Helix) to 20 months (Activator). Success rates were highest for Quad Helix (82%) and Removable Plates (65%), while lower rates were recorded for Extraoral Traction (57%) and Activators (56%). Failures were mainly linked to poor compliance. The results from this large cohort study on interceptive orthodontics provide real-world evidence that although success rates were lower than in randomized trials, the outcomes reflect routine care conditions. The findings highlight the importance of compliance, appliance selection, and treatment timing. The dataset offers a foundation for future longitudinal evaluations of long-term outcomes and cost-effectiveness.

Obstructive sleep apnea (OSA) is characterized by recurrent collapses of the upper airway during sleep. Although nasal obstruction has been identified as an independent risk factor for OSA and extensively studied, the relationship between nasal anatomical structures and OSA remains poorly understood. The objective of this study was to determine the relationship between the nasal cross-sectional area (CSA), as measured by magnetic resonance imaging in the supine position, and the presence of OSA, as well as to investigate its correlation with OSA severity. In this cross-sectional study, a total of 111 participants were enrolled, comprising 88 patients with OSA and 23 healthy controls. All participants underwent polysomnography to determine their apnea-hypopnea index (AHI). Subsequently, MRI scans were performed in the supine position to measure CSA at distances of 1.5, 2, 2.5, 3, 4, 5, and 6 cm posterior to the most anterior point of the nasal cavity. Participants were stratified into groups based on AHI severity, and statistical analyses were conducted to determine the correlation between CSA measurements and the AHI. Significant intergroup differences were observed in the minimum CSA at the 2.5 and 4.0 cm levels. No difference was found in the sum of nasal CSA at any level. Furthermore, no group differences were found in either nasal cavity volume or surface area. A comparison between healthy individuals and OSA patients revealed that advanced age, a higher body mass index, male sex, and a reduced total minimum nasal cross-sectional area (TMCA) were independent and significant predictors of OSA. TMCA was identified as a predisposing factor for OSA, but it was not found to be associated with the severity of the condition. Furthermore, long-term, severe OSA may contribute to an enlargement of the CSA.

This study aimed to comparatively evaluate the effects of three different expansion methods [rapid palatal expansion (RPE), modified alternate rapid maxillary expansion and constriction (Alt-RAMEC), and skeletal anchorage (SA)] combined with maxillary protraction (MP) on the soft tissue profile using 3D stereophotogrammetry. A total of 51 patients aged between 8 and 12 years with Class III malocclusion who were in the growth and development period were included in the study. The patients were divided into three groups according to the expansion technique applied. Pre- and post-treatment soft tissue changes were analyzed using 3D stereophotogrammetric images. Soft tissue measurements revealed significant changes across all groups. Post-treatment volumetric analysis showed significant increases in midface, nasal, and upper lip volumes, alongside reductions in lower lip and chin volumes across all protocols (P < .01). The SA group achieved the highest significant increases in midface (2754 ± 246 mm3), nasal (1156 ± 143 mm3), and upper lip volumes (611 ± 82 mm3) compared with the RPE and Alt-RAMEC groups (P < .01). While alar base width increase was most significant in the RPE group (P < .001), nasal tip protrusion and the greatest decrease in upper lip length and angle were most pronounced in the SA group (P < .05). SA-supported MP offers the potential to more effectively control soft tissue aesthetics by minimizing undesirable dental and vertical skeletal side effects. This method is superior to other traditional approaches in providing predictable and aesthetically pleasing soft tissue changes.

Quantification of the effect of orthodontic treatment on the gingival mircroaesthetics is lacking. The aim of this exploratory investigation was to investigate the effect of fixed orthodontic appliance therapy on gingival aesthetics associated with the anterior maxillary dentition. A bespoke gingival aesthetic criterion was used to assess 150 sets of pre- and post-treatment intra-oral photographs from a consecutively treated patient sample who had completed fixed appliance therapy. Five assessors rated the images assigning a score per criterion. Reliability of the method was assessed with concordance correlation coefficient (CCC) and Bland-Altman limits of agreement (LOA). Differences by timepoint, assessors, and treatment characteristics were assessed with statistical tests or generalized linear models at α = 5%. In the sample of 150 cases, the most common pre-treatment incisor classification was Class III (n = 57) followed by Class II Div 1 (n = 52). The majority of cases were treated on a nonextraction basis (n = 95) and involved orthodontic appliances only (n = 134). The CCC and LOA values for the aesthetic gingival criterion ranged from good-excellent. Average aesthetic summary scores differed from before pre-treatment [median = 33.9; interquartile range (IQR) = 24.5-45.2] and post-treatment (median = 75.8; IQR = 65.2-85.3) to a significant degree (mean difference = 38.5; standard deviation = 17.8; P < 0.001). No difference in aesthetic criterion points score was evident for treatment plan (nonextraction vs extraction) (P = 1.00) and treatment type (orthodontic only or orthognathic) (P = 0.52). Considerable variation in summary scores among assessors with different specialty/grades was seen (P < 0.001). Gingival aesthetic ratings were undertaken in isolation without the assessment of specific contributions made by soft and hard tissues, and changes in tooth position. Orthodontic treatment with fixed appliances can have a positive effect on the gingival margin, gingival zenith, gingival embrasure, connector area, and overall rating of gingival symmetry of the anterior maxillary teeth. However, aesthetic ratings depend on the assessor.

Skeletal Class II malocclusion is commonly treated with functional appliances, but bulkiness and discomfort usually affect the compliance. Modifications of these appliances using clear thermoplastic materials could improve comfort and esthetics; though clinical evidence remains limited. To assess the clinical effectiveness of a Modified Twin Block (MTB) appliance, fabricated from 2 mm biocompatible polyethylene terephthalate modified with Glycol (PETG) thermoplastic material, in comparison with the Conventional Twin Block (CTB), for treatment of skeletal Class II due to mandibular retrognathism. This multicenter, single-blinded randomized clinical trial included 50 adolescents, at the peak of pubertal growth (CS -3). Patients were randomly assigned to two parallel groups treated with either a CTB or MTB appliance, both incorporating a midline screw for maxillary expansion. Appliances were worn full-time and the expander was activated twice weekly. The records including cephalograms were taken pre- and post-treatment to evaluate skeletal (sagittal and vertical) and soft tissue changes. Dental arch expansion was assessed using standardized 3D digital model superimposition on palatal landmarks, and overjet/overbite changes were clinically recorded. Patient perception was evaluated using a validated questionnaire. Data were analyzed using paired and independent t-tests. All patients completed the trial without dropout. Baseline characteristics were comparable between groups, with no significant differences in 20 out of 24 variables. Both the CTB and MTB groups showed significant improvements in skeletal, soft tissue, and dental parameters post-treatment (P < 0.05). Between-group comparison revealed a statistically significant improvement in ANB angle favoring the MTB group (P = 0.004), while vertical skeletal and soft tissue changes showed no significant differences (P > 0.05). The MTB group also demonstrated a significantly greater overbite reduction (P = 0.005) and higher dental arch expansion (P = 0.001), particularly in the molar region. No significant difference was found in active treatment duration. Patient perception data showed significantly more favorable experiences with the MTB appliance in 13 out of 36 questionnaire items, particularly regarding comfort, hygiene, function, and psychosocial impact. Double blinding was not feasible due to clear visual differences between the appliances. The MTB appliance is effective in treating growing patients with skeletal Class II due to mandibular retrognathism and is comparable with slight advantageous results to CTB appliance. NCT06116500.

To assess the effect of smile shape on self-perceived smile attractiveness in young adults. The study included 601 participants (393 females, 208 males). Three-dimensional smiling facial images were captured using the 3dMD stereophotogrammetry system (3dMD, Atlanta, USA). Participants rated their smile attractiveness using a visual analogue scale (0-100). Smile shape was described with 62 landmarks, which were aligned using Generalized Procrustes Superimposition to extract shape coordinates. Principal component analysis (PCA) was used to reduce dimensionality and derive shape PCs. The association between smile shape and self-perceived smile attractiveness was examined using multivariate regression models, performed separately for females and males. Allometric effects were assessed using standardized residuals of shape PCs. Statistical significance was set at P < .05. In males, no statistically significant association was found between smile shape and self-perceived smile attractiveness (P = .6; η2 = 0.065). In females, a significant association was observed (P = .001; η2 = 0.093), with more attractive smiles displaying greater width, height, and curvature. Allometric analysis revealed a strong effect of size on shape (η2 = 0.468; P < .001). After controlling for this effect, the association in females was no longer statistically significant (P = .08), although a moderate effect size persisted (η2 = 0.069), indicating that the effect remained but was statistically less robust. Smile shape significantly affects self-perceived attractiveness, particularly in females, with effects related to proportionally larger smiles. This finding highlights known sex-based differences in aesthetic self-perceptions, as well as the preference for broader smiles.

Functional appliances are widely used for Class II correction in growing patients, and their potential influence on upper-airway dimensions has been examined in several systematic reviews. However, methodological quality, overlap of primary studies, and credibility of evidence remain uncertain. To synthesize evidence from published systematic reviews and meta-analyses on functional appliances and airway dimensions in growing Class II patients, and to evaluate methodological quality, overlap, and credibility of evidence. Comprehensive electronic searches of PubMed, Embase, Cochrane Library, Scopus, Web of Science, and supplementary sources identified eligible systematic reviews up to August 2025. Systematic reviews or meta-analyses assessing airway changes after functional-appliance therapy in normal growing Class II patients with true external or growth-matched controls were included. Four systematic reviews encompassing 39 unique primary studies were retained. Methodological quality was assessed using the Joanna Briggs Institute (JBI) checklist and the Risk of Bias in Systematic Reviews (ROBIS) tool; study overlap was quantified by the Corrected Covered Area (CCA); credibility was evaluated using Ioannidis' classification; and evidence certainty was graded with the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) tool. Meta-analyses revealed significant oropharyngeal enlargement: superior pharyngeal space + 1.73 mm (95% CI 1.13-2.32), middle + 1.52 mm (95% CI 1.09-1.96), and inferior + 1.25 mm (95% CI 0.66-1.84). Oropharyngeal airway volume increased by 2356 mm³ (95% CI 1276-3436) and nasopharyngeal volume by 382 mm³ (95% CI 141-623). Changes in posterior airway space (+0.52 mm, 95% CI -0.20 to 1.24) and upper-airway thickness were not significant. ROBIS classified four reviews as low-risk and two as high-risk. Study overlap was moderate (CCA = 6.8%). By Ioannidis' criteria, most outcomes were weak (Class IV) or non-significant. GRADE certainty was low to very low, mainly due to risk of bias, heterogeneity (I² up to 90%), and imprecision. Functional appliances yield modest yet statistically significant enlargement of oropharyngeal airway dimensions in growing Class II patients, with the effect being more pronounced with removable appliances. Nevertheless, evidence credibility remains weak, and overall certainty is low. Results should be interpreted with caution, and future studies should employ prospective, volumetric, growth-controlled, and standardized protocols. This umbrella review was registered with PROSPERO (CRD42023408859).

This study aims to evaluate postoperative craniocervical changes after bilateral sagittal split ramus osteotomy (BSSRO), to test mandibular translation and rotation as predictors, and to explore their coupling with tongue and hyoid adaptations. A total of 210 patients (88 males, 122 females; 18-58 years) were equally divided into skeletal Classes I-III. Cephalograms in natural head posture were obtained pre- and postoperatively. Craniocervical change (ΔNSL/OPT) was the primary outcome. Mandibular translation (ΔGo-Me) and rotation (ΔFH-MP) served as predictors, with tongue and hyoid variables as secondary outcomes. Reliability was assessed using intraclass correlation coefficients (ICCs). Statistical analyses included analysis of variance (ANOVA), correlation, and multivariable regression. Measurement reproducibility was excellent (ICC > 0.92). Mandibular advancement (Class II) and setback (Class III) produced class-specific changes in ΔGo-Me and ΔFH-MP. Postoperatively, Class II showed cervical flexion (-3.09° ± 7.12°) whereas Class III showed cervical extension (+2.92° ± 5.48°, P < .001). ΔNSL/OPT correlated with ΔFH-MP (r = 0.25, P = .002) and ΔGo-Me (r = 0.17, P = .017), though only ΔFH-MP remained significant in regression (β ≈ 0.47° per 1° rotation). ΔNSL/OPT was most strongly correlated with ΔSNH (r = 0.62, P < .001), indicating coordinated craniocervical-hyoid adaptation. Tongue showed modest lengthening, flattening, and anterior shift across both advancement and setback groups. Cervical extension after BSSRO is primarily driven by mandibular rotation rather than translation, underscoring the clinical importance of incorporating rotational vectors into surgical planning. Coupled tongue-hyoid adaptations reflect early neuromuscular compensation, with potential implications for long-term stability and functional outcomes.