Skeletal Class III phenotype: Link between animal models and human genetics: A scoping review.

This study aimed to identify evidence from animal studies examining genetic variants underlying maxillomandibular discrepancies resulting in a skeletal Class III (SCIII) malocclusion phenotype. Following the Manual for Evidence Synthesis of the JBI and the PRISMA extension for scoping reviews, a participant, concept, context question was formulated and systematic searches were executed in the PubMed, Scopus, WOS, Scielo, Open Gray, and Mednar databases. Of the 779 identified studies, 13 met the selection criteria and were included in the data extraction. The SCIII malocclusion phenotype was described as mandibular prognathism in the Danio rerio, Dicentrarchus labrax, and Equus africanus asinus models; and as maxillary deficiency in the Felis silvestris catus, Canis familiaris, Salmo trutta, and Mus musculus models. The identified genetic variants highlight the significance of BMP and TGF-ß signaling. Their regulatory pathways and genetic interactions link them to cellular bone regulation events, particularly ossification regulation of postnatal cranial synchondroses. In conclusion, twenty genetic variants associated with the skeletal SCIII malocclusion phenotype were identified in animal models. Their interactions and regulatory pathways corroborate the role of these variants in bone growth, differentiation events, and ossification regulation of postnatal cranial synchondroses.

The association between malocclusion and health-related quality of life in adolescents: A mediation analysis.

This study investigated the role of oral health-related functional limitations and social well-being, self-perceived health, psychosocial factors, and social support in mediating the impact of malocclusion on health-related quality of life (HRQoL). A school-based 6-month cohort study was conducted with 376 12-year-old deprived adolescents. Measures at baseline included malocclusion (DAI score), dental caries, sociodemographic characteristics, psychosocial traits (self-esteem, sense of coherence, oral health beliefs), and social support. The oral health-related functional limitations and symptoms (social well-being) domains of the CPQ11-14 , self-perceived health, and HRQoL (Kiddo-KINDL) were evaluated at the 6-month follow-up. Associations between observed and latent variables (social support, psychosocial factors, and HRQoL) were evaluated using structural equation modelling, according to the Wilson and Cleary theoretical model. Malocclusion was indirectly associated with worse HRQoL, mediated by functional limitations, social well-being, and self-perceived health. Better psychosocial status was directly associated with better HRQoL, and higher social support was indirectly associated with better HRQoL via psychosocial factors. Dental caries experience, female sex, and lower family income were indirectly associated with worse HRQoL. The impact of malocclusion on HRQoL was mediated by oral health-related functional limitations, social well-being, and self-perceived health. Sociodemographic and psychosocial factors, and social support also impacted HRQoL.

Asymmetry in Class II subdivision malocclusion: Assessment based on 3D surface models.

INTRODUCTION: There is currently no consensus in the literature whether the aetiology of a Class II subdivision is dental, skeletal or both. The aim of this study was to identify and quantify skeletal and dental asymmetries in Class II subdivision malocclusions. METHODS: CBCTs from 33 Class II subdivision malocclusion patients were used to construct 3D volumetric label maps. Eighteen landmarks were identified. The original scan and associated 3D volumetric label map were mirrored. Registration of the original and mirrored images relative to the anterior cranial base, maxilla and mandible were performed. Surface models were generated, and 3D differences were quantified. Statistical analysis was performed. RESULTS: Anterior cranial base registration showed significant differences for fossa vertical difference, fossa roll, mandibular yaw, mandibular lateral displacement and lower midline displacement. Regional registrations showed significant differences for antero-posterior (A-P) mandibular length, maxillary roll, A-P maxillary first molar position, maxillary first molar yaw and maxillary first molar roll. Class II subdivision patients also show an asymmetric mandibular length as well as an asymmetric gonial angle. Moderate correlations were found between the A-P molar relationship and fossa A-P difference, mandibular first molar A-P difference, maxillary first molar A-P difference and maxillary first molar yaw. CONCLUSIONS: This study suggests that Class II subdivisions can result from both significant skeletal and dental factors. Skeletal factors include a shorter mandible as well as posterior and higher displacement of the fossa on the Class II side, resulting in mandibular yaw. Dental factors include maxillary and mandibular first molar antero-posterior asymmetry.

Malocclusion or laterorhinia: Which one impacts aesthetic facial perception the most?

INTRODUCTION: This study aimed to evaluate the perception of facial attractiveness when nose and teeth, together or isolated, present different degrees of disharmony. The secondary objective was to compare the perception of laypersons with that of dentists. MATERIALS AND METHODS: This cross-sectional observational study included 112 individuals (58 laypersons and 54 dentists) that evaluated 6 manipulated images of the face of the same model, scoring their attractiveness using 10 cm Visual Analogue Scales (VAS), with least and most attractive at the left and right anchors, respectively. The images contained manipulations performed only on the nose (laterorhinia) and mouth (misaligned teeth), as follows: (1) standard photograph, with symmetrical nose + aligned teeth; (2) 2 mm nasal deviation + aligned teeth; (3) 4 mm nasal deviation + aligned teeth; (4) symmetrical nose + misaligned teeth; (5) 2 mm nasal deviation + misaligned teeth and (6) 4 mm nasal deviation + misaligned teeth. We used the repeated measures ANOVA test and Tukey's post-test for intra-group comparison of the images. The independent t-test was used for inter-group comparison of each image. RESULTS: In the laypersons' group, the highest grades were given to images with aligned teeth and the lowest to misaligned teeth (smallest mean difference = 2.88 cm). For this group, there was no statistically significant difference (P-values ranged from .988 to 1.000) between scores of the three images in which teeth were aligned (range of 7.70-7.78 cm). In the group of dentists, highest grades were given to images with aligned teeth and the lowest to misaligned teeth. Difference between images 3 and 4 was not statistically significant (P = .204). All other differences between any image of straight teeth and any image with misaligned teeth were significant and the smallest mean difference between the two groups of images was 1.87 (P = .039). However, in the images with aligned teeth, there was also a statistically significant difference with higher scores to the images with symmetrical nose in contrast with those with significant laterorhinia (mean difference = 1.03 cm). CONCLUSION: Teeth disharmonies had a more negative impact on the aesthetic perception of the face than did nose deviations, for both dentists and laypersons.

Comparison of the efficiency of initial dental alignment with Invisalign® aligners changed every 7 or 14 days in mature adults: Randomized clinical trial.

OBJECTIVE: To compare the anterior crowding correction after sequential use of the first 5 aligners between two aligner exchange protocols (7 and 14 days) in mature adult patients. MATERIALS AND METHODS: Thirty-six patients over 35 years who received orthodontic treatment with Invisalign® were randomly allocated to two different aligner replacement sequence protocols: Group 1: exchange every 7 days (n = 18); and Group 2: exchange every 14 days (n = 18). All patients were scanned with iTero Element 5D® (Align Technology) in two treatment times: at pre-treatment (T1) and after using the first five aligners (T2). Little's Irregularity Index (LII) and arch widths were evaluated with OrthoCAD software. Intra and intergroup comparisons were performed with the dependent and independent t-tests. The results were considered significant for P < .05. RESULTS: Thirty-five patients completed the study. Both groups' maxillary and mandibular Irregularity Indexesi were significantly lower at T2. There was no significant difference in inter-canine, inter-premolar, and intermolar distances. G2 (14 days) presented a greater decrease in mandibular irregularity than G1 (7 days). CONCLUSION: Both exchange protocols (7 and 14 days) effectively correct anterior crowding in the initial phase of orthodontic treatment with aligners in mature adult patients. However, the 14-day exchange protocol provided a greater correction in mandibular anterior crowding in the evaluated period than the 7-day exchange protocol.

Evaluation of modified clear Twin Block aligner in treating adolescents with skeletal class II malocclusion: A two-centre cephalometric study.

INTRODUCTION: The purpose of this study was to evaluate the therapeutic effect of modified clear Twin Block (CTB) aligner and traditional twin block (TB) appliance from skeletal, dentoalveolar and soft tissue changes in adolescents with skeletal class II malocclusion. METHODS: A total of 80 adolescents, included in this study from two medical centres, were distributed into CTB group, TB group and control group based on the treatment they received. Lateral cephalograms at pre-treatment (T1) and post-treatment (T2) were measured by modified Pancherz's cephalometric analysis, and dentoskeletal and soft tissue changes were analysed by independent-sample t-test, paired-sample t-test, ANOVA test and Scheffe's Post Hoc test. RESULTS: Seventy-five adolescents completed the study, including 32 in the CTB group, 32 in the TB group and 11 in the control group. Both CTB and TB treatment showed significant differences in most dentoskeletal and soft tissue measurements. Compared with the control group, improvements were observed in class II molar relationship through significant different in S Vert/Ms-S Vert/Mi in the CTB group (P < .01) and the TB group (P < .001), as well as deep overjet through significant different in S Vert/Is-S Vert/Ii in the CTB group (P < .001) and the TB group (P < .001). Besides, the CTB group also showed less protrusion of lower incisors and resulted in a more significant improvement in profile with fewer adverse effects on speaking, eating and social activities. CONCLUSIONS: For adolescents with skeletal class II malocclusion, CTB appliance was as effective as TB on improving dentoskeletal and soft tissue measurements, featuring more reliable teeth control and patient acceptance.

A comparison of maxillary posterior changes following facemask therapy: Skeletal anchorage versus tooth-borne anchorage.

OBJECTIVE: To compare changes in the maxillary posterior structure as seen in cone-beam computed tomography (CBCT) images resulting from facemask therapy using skeletal (miniplate/FM) anchorage versus tooth-borne anchorage (RME/FM). MATERIALS AND METHODS: A retrospective study was conducted on 20 patients divided into the miniplate/FM group (nine patients aged 9.5 ± 1.4 years) and the RME/FM group (11 patients aged 9.2 ± 1.4 years). CBCT images before and after facemask therapy were evaluated to assess changes in the maxillary posterior structure. RESULTS: The miniplate/FM group had greater advancement of the maxilla and midface compared to the RME/FM group (p < .05). Specifically, there was about three times more advancement of the pterygomaxillary suture in the miniplate/FM group than in the RME/FM group (p < .05). Moreover, the advancement of the pterygomaxillary suture was about half the advancement of A point in the miniplate/FM group, while only about 25% in the RME/FM group. Finally, the miniplate/FM group showed an increase in the transverse dimension of the posterior and superior parts of the maxilla (p < .05). CONCLUSION: There was greater forward movement of the pterygomaxillary suture with facemask therapy using the skeletal anchorage compared to tooth-borne anchorage, leading to a more significant advancement of the maxilla and midface.

Temporomandibular joint disc position and shape in patients submitted to two protocols of rapid maxillary expansion and face mask therapy: A randomized clinical trial.

OBJECTIVE: The objective of this prospective study was to assess possible changes in the position and shape of the temporomandibular joint (TMJ) articular disc in patients treated with two protocols of rapid maxillary expansion (RME) and face mask (FM) therapy. METHODS: A sample of 88 patients with Class III or Class III subdivision malocclusions, aged between 6 and 13 years, were consecutively selected and divided into three groups (G): G1-34 patients were treated with RME, followed by FM therapy; G2-34 patients were treated using RME according to modified alternate rapid maxillary expansion and constriction (ALT-RAMEC) protocol, followed by FM therapy. These treated groups were randomly (1:1 allocation ratio) distributed according to the two treatment protocols. G3 - Control Group - 20 untreated patients were followed. Magnetic resonance imaging (MRI) TMJs were obtained before (T1) and after (T2) a treatment period or follow-up. McNemar test, Fisher's exact test and intra- and inter-observer concordance (K) were performed (p ≤ .05). RESULTS: There were no statistically significant differences in the baseline cephalometric variables at T1 between the groups. There were statistically significant differences between the groups (p < .001) in relation to the disc shape in T1, since G1 (8 TMJs -11.76%) presented higher occurrences of altered forms in comparison with G2 (no changes). No significant differences were observed in disc position CM and OM (G1 - p > .999; G2 - p = .063; G3 - p = .500) and shape (G1 - p > 0.999; G2 - p = .250; G3 - not calculable), between T1 × T2, in any of the groups studied. CONCLUSION: The two treatment protocols did not have adverse effects on the position and shape of the TMJ disc, in a short-term evaluation.

Headgear therapy in children with Class II malocclusion and the role of compliance on treatment outcome: A nine-month randomized controlled trial.

OBJECTIVES: To evaluate three-dimensional movements of maxillary teeth during headgear treatment in Class II growing children, using digital analytical tools, and to determine the effects of compliance on these movements. MATERIALS AND METHODS: A 9-month parallel-group randomized controlled trial was carried out on 40 children with Class II malocclusion, aged 8-12 years, half assigned to receive a cervical headgear and half to a no-treatment group, using block randomization. Subjects in the treatment group were instructed to wear the headgear for 12 hours daily and monitored using an electronic module. After 9 months, the following dental outcomes were measured: first maxillary molar distalisation, rotation, tip and torque, arch depth, and interpremolar and intermolar distances. Caregivers and participants were not blinded to group assignments, but those assessing outcomes were. Linear regression models were used to detect differences between groups and correlation coefficients to find correlations between compliance and dental outcomes. RESULTS: All 40 included patients were analysed. A significant difference in molar distalisation was observed between the treatment (1.2 mm) and control groups (-0.2 mm). Arch depth change was also increased to a larger extent in the treatment groups (1.3 mm vs 0.1 mm), as was the interpremolar distance (1.9 mm vs 0.4 mm). In contrast, no significant differences in molar rotation or torque change were observed. With regard to compliance, average compliance was 55%. A significant correlation was found between molar distalisation and compliance in the treatment group. CONCLUSIONS: Headgear therapy has significant effects on molar distalisation, arch depth, and arch width. Compliance has a significant positive effect on molar distalisation.

Three-dimensional evaluation of mandibular lingula: Comparisons of skeletal angle classifications and growth patterns.

OBJECTIVES: This study aimed to evaluate the position of the mandibular lingula (ML) in adult patients (aged between 18 and 35 years old) with different skeletal and growth patterns using cone-beam computed tomography (CBCT). DESIGN: Cross-sectional. SETTING: Dentistry department of University. SUBJECTS: Subjects comprised CBCT images of 150 adult patients, including 300 rami. METHODS AND MATERIALS: In total, 150 CBCT aged between 18 and 35 were selected and divided into three main groups of 50 samples based on their skeletal relationships (classes I, II and III). Patients were subdivided based on their growth pattern (vertical vs. horizontal), resulting in 25 samples per subgroup. Distances between the mandibular lingula and occlusal plane (ML-OP), sigmoid notch (ML-SN), external oblique ridge (ML-EOR), internal oblique ridge (ML-IOR), posterior border of the ramus (ML-PBR), inferior border of the ramus (ML-IBR), and horizontal and vertical distances to the mandibular foramen (ML-hMF and ML-vMF). One-way ANOVA variance analysis was employed to compare different angle classifications, and Bonferroni analysis was used for multiple comparisons. The Student's t-test was also used to compare growth patterns within each main group and genders within the subgroup. RESULTS: The study revealed statistically significant differences in the position of the mandibular lingula between different angle classifications, growth patterns, and genders. Class II samples showed a more anterior position of the ML, whereas Class III samples displayed a more posterior position of the ML. Patients with horizontal growth patterns and Angle Class III had a more posteriorly positioned ML. Gender differences were observed, particularly in Class I and Class III classifications, suggesting that gender may influence the variability of ML position in these specific classifications. CONCLUSION: The position of the mandibular lingula showed high variability among individuals with different angle classifications, growth patterns and genders.

Impact of protraction or orthognathic surgery for class III malocclusion on longitudinal quality of life in patients with cleft lip and palate.

OBJECTIVES: This study assessed overall quality of life (QoL) over time in youth with cleft lip and palate (CLP) undergoing maxillary protraction treatment or orthognathic surgery for class III malocclusion to identify any differences in QoL based on treatment group and outcome success. MATERIALS AND METHODS: A prospective longitudinal cohort study was conducted in two pediatric hospitals. The Short Form Health Survey (SF-12) measured physical and mental QoL prior to treatment, at maximal correction, at treatment completion, and at 1-year post treatment. Analyses included one-sample, two-sample, and paired t-tests and analyses of variance and covariance. RESULTS: Participants (N = 91) either completed protraction (n = 53) at age 11-14 or surgery (n = 38) at age 16-21. Participants were mostly Latinx (67%) males (55%) born with unilateral CLP (81%) and there were no demographic differences between the two groups other than age. The total sample's QoL was in the average range and significantly higher than national norms. No significant differences were found in QoL-based outcome success; however, the protraction group showed a gradual physical QoL improvement over time, while the surgery group experienced a temporary drop in physical QoL postoperatively. At treatment completion, higher physical QoL was associated with higher socioeconomic status. At a year post treatment, mental QoL was significantly higher for males. CONCLUSION: Both protraction and surgery appear to be acceptable treatment options in terms of overall QoL for youth with CLP. While treatment success did not impact QoL, there were some differences in physical QoL coinciding with the treatment phase as well as individual factors.

A finite element study comparing Advansync® and Twin Block in mandibular anterior repositioning.

OBJECTIVE: This study aims to utilize the finite element method (FEM) to compare the dentoalveolar and mandibular effects associated with anterior mandibular repositioning using AdvanSync® (ADV) and Twin Block (TB). METHODS: A patient with Class II skeletal malocclusion and mandibular retrognathism was selected. A TB appliance was subsequently applied. Computed Tomography (CT) scans were acquired at the beginning of treatment (T1) and 8 months later (T2). Concurrently, a numerical TB model was validated through FEM simulations, which were compared with the T2 results. The ADV appliance was virtually simulated to evaluate stress and deformation on the condyle, symphysis, first lower molar and lower central incisors. RESULTS: Both simulations demonstrated significant mandibular advancement. However, ADV led to less incisor proclination and more molar intrusion compared to TB. ADV exhibited increased stress in the lower molar area, while TB had higher stress in the lower incisor region. Stress and deformations in the condyle and mandibular symphysis were similar in both simulations, with the highest stress observed at the condylar neck and the lowest at the upper pole of the condylar head. CONCLUSIONS: Both appliances achieved similar levels of mandibular advancement, with greater proclination of the lower central incisors and more widespread distribution of stress and molar intrusion when using ADV compared to TB.

Mapping the evolving trend of research on Class III malocclusion: a bibliometric analysis.

OBJECTIVES: This study aimed to provide visualized knowledge maps to show the evolving trends and key focal points of Class III malocclusion research through a comprehensive bibliometric analysis. MATERIALS AND METHODS: Class III malocclusion research published between 2000 and 2023 was retrieved from the Web of Science Core Collection. VOSviewer was utilized to count the citation and publication number of authors, institutions, countries and journals. Co-occurrence, co-citation, and cluster analyses and burst detection were conducted using CiteSpace. RESULTS: A total of 3,682 publications on Class III malocclusion were included in the bibliometric analysis. During 2000-2023, both the annual publication count and citation frequency exhibited a gradual upward trajectory, with a noticeable surge in recent years. In terms of production and citation counts of Class III malocclusion research, the core journal is the American Journal of Orthodontics and Dentofacial Orthopedics. Furthermore, apart from the primary keyword 'Class III malocclusion', 'orthognathic surgery' was identified as keyword with the most frequency. The cluster analysis of cited references reveals that the research focal points have shifted to 'skeletal anchorage' and 'surgery-first approach'. Furthermore, the burst detection identified 'quality of life' as a potential research hotspot since it has recently gained increasing scholarly attention. CONCLUSIONS: The current study provides scholars with the knowledge maps of evolving trends and prominent topics of Class III malocclusion research and a summary of research progress on various priorities during different periods. These findings are expected to provide a valuable guidance to facilitate the future research on Class III malocclusion.

Evaluation of the impact of orthodontists' smile with malocclusions on social media and professional credibility.

OBJECTIVES: This study assessed laypeople's perceptions of orthodontist credibility based on malocclusions and whether these views affect their choice to seek treatment. Eye-tracking technology and questionnaires were utilized. MATERIALS AND METHODS: Ninety-five lay raters, through eye tracking and a questionnaire, assessed 12 images of orthodontists with malocclusions. Malocclusions were categorized by the Index Of Treatment Need (IOTN) as grade 1 (near ideal), 3 (anterior crowding), and 5 (with diastemas). Fixation points were recorded, and credibility was gauged via questionnaires. A Mentimeter word cloud was generated. RESULTS: IOTN 1 orthodontists were viewed as more credible than IOTN 3 (p < 0.001) and 5 (p < 0.001). Raters were more willing to receive treatment from IOTN 1 orthodontists. The focus for IOTN 1 was between eyes and mouth, while IOTN 3 and 5 were on the mouth. "Crooked teeth" and "spacing" were predominant in word clouds for IOTN 3 and 5. CONCLUSION: Orthodontists with an IOTN grade 1 rating were perceived as more competent, reliable, and professional, thus making it more likely for laypeople to choose them as their preferred providers. CLINICAL RELEVANCE: The smiles of professionals play a significant role in laypeople's decision to choose them as their orthodontist, and strategic utilization of social media can effectively deliver health information to a larger audience in a faster and more direct manner.

Does malocclusion affect ingestion: a systematic review.

OBJECTIVES: The multifactorial aspect of malocclusions and their consequences on ingestion function is rarely described in the literature. The aims of this review are (i) to investigate the relationship between oral ingestion and malocclusion and (ii) to gather malocclusion tools that could help screen subjects at risk of malocclusion-related ingestion disorders. MATERIAL AND METHODS: A systematic review was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocol (PRISMA-P 2015) guidelines. The analysis methods and inclusion criteria have been documented in a protocol published in the Prospective International Register of Systematic Reviews (PROSPERO) under the registration number CRD42023395840. The bibliographic search involved the PubMed®, Cochrane and PROSPERO databases. RESULTS: A total of 29 articles published between 2007 and 2023 were retained by the search criteria for the qualitative synthesis. Twenty of the studies found that the severity of malocclusion has a negative impact on oral ingestion. This review highlights that malocclusion and ingestion impairments are associated but it is not possible to determine causality due to the observational approach of many of the studies. CONCLUSION: Malocclusion has a negative impact on ingestion function. During orthodontic consultations, particular interest should be directed towards chewing, biting, and swallowing disorders, which can affect patients' nutritional status. This review offers arguments for designing further studies assessing the extent to which malocclusions may affect nutritional status. CLINICAL RELEVANCE: Orthodontic treatment should focus on improving patients' ingestion.

Site and severity of facial asymmetry after bimaxillary surgery for class III deformity: a case-control study.

OBJECTIVES: The study aimed (1) to evaluate the site and severity of facial asymmetry in Class III patients before and after bimaxillary surgery, and (2) to identify the influence of initial severity and positional jaw asymmetry on residual facial asymmetry. MATERIALS AND METHODS: Preoperative and postoperative cone-beam computed tomography of 65 patients with Class III facial asymmetry who underwent bimaxillary surgery were evaluated. Five midline and 14 paramedian facial soft tissue landmarks were identified to assess facial asymmetry. The outcomes were compared to a control group consisting of 30 age- and gender-matched Class I subjects. The postoperative positional jaw asymmetry (i.e., shift, roll, yaw) of each osteotomy segment (maxilla, mandible, chin, ramus) was also measured. RESULTS: Before surgery, the asymmetry was more severe at the chin, middle and lower contour. Bimaxillary surgery effectively corrected facial asymmetry, particularly in achieving normalization of chin deviation. However, significant asymmetry persisted postoperatively in the middle and lower contour (p < 0.001 and p < 0.01, respectively), which was affected by the positional ramus asymmetry in the roll and shift. CONCLUSIONS: Deviation of the chin, middle and lower contour contributed significantly to overall facial asymmetry in Class III asymmetry. Despite normalization of the chin deviation after bimaxillary surgery, asymmetry persisted at the middle and lower contour, primarily as the result of insufficient correction of the positional ramus asymmetry. CLINICAL RELEVANCE: Understanding the residual asymmetry after bimaxillary surgery is important for minimizing deviation and optimizing the surgical planning for its correction.

Influence of malocclusion on sleep bruxism and orofacial pain: data from a study in school children.

OBJECTIVES: This cross-sectional school-based study explored the influence of malocclusion on temporomandibular disorders (TMD) pain complaints, and whether this association would be mediated by sleep bruxism in a representative sample of 7- to 8-year-old children. METHODS: Path analysis estimated direct, indirect, and total effects of occlusal features on sleep bruxism and TMD pain in 7- to 8-year-old children. Occlusal features were assessed with Dental Aesthetic Index (DAI), orofacial pain complaints using the TMD pain screener, possible sleep bruxism based on self-reports, and probable sleep bruxism based on self-reports combined with clinical findings. Structural equation modeling analyzed data with confounding factors. RESULTS: From 580 participants, possible sleep bruxism was observed in 136 children (31.5%), probable sleep bruxism in 30 children (6.7%), and TMD pain complaints in 78 children (13.8%). Malocclusion had no direct effect on either possible sleep bruxism [standardized coefficient (SC) 0.000; p = 0.992], or TMD pain complaints (SC - 0.01; p = 0.740). When probable sleep bruxism was set as the mediator of interest, malocclusion did not directly affect probable sleep bruxism (SC 0.01; p = 0.766), nor TMD pain complaints (SC - 0.02; p = 0.515). A direct effect of probable sleep bruxism on TMD pain complaints was observed with an SC of 0.60 (p < 0.001). However, in neither case, malocclusion indirectly affected TMD pain complaints via bruxism. CONCLUSION: Malocclusion in 7- to 8-year-old children did not directly influence possible or probable sleep bruxism or TMD pain complaints. Instead, probable sleep bruxism was strongly associated with TMD pain complaints. CLINICAL SIGNIFICANCE: The impact of occlusal features on TMD pain complaints and bruxism has been a long-standing controversy in dentistry. However, the scientific literature linking this association may be inconsistent, mainly due to biased sample selection methods with inadequate consideration of confounders. Further research should try to identify additional risk factors for TMD pain in addition to probable sleep bruxism in children.

Autistic individuals have worse oral status than neurotypical controls: a systematic review and meta-analysis of observational studies.

OBJECTIVE: To compare dental caries, oral hygiene, periodontal status, bruxism, malocclusion, tooth loss, and salivary alterations between autistic and typical developing individuals. MATERIAL AND METHODS: Observational studies presenting clinical measures of oral outcomes between autism spectrum disorder (ASD) individuals and controls. EMBASE, LILACS, PubMed, PsycINFO, Scopus, Web of Science, Google Scholar, and ProQuest were searched up to June 26, 2023. Pairs of reviewers independently conducted study selection, data extraction, and assessments of methodological quality and certainty of evidence. Meta-analyses of standardized mean differences (SMD) and risk ratio (RR) were performed. RESULTS: A total of 47 studies comprising 6885 autistic individuals were included in the review. Autistic individuals had significantly higher severity of dental-caries experience in primary teeth (SMD 0.29, 95%CI 0.02, 0.56), of dental plaque presence (SMD 0.59, 95%CI 0.24, 0.94), and of gingivitis (SMD 0.45, 95%CI 0.02, 0.88). Autistic individuals showed higher probability of occurrence of gingivitis (RR 1.34, 95%CI 1.08, 1.66,), bruxism (RR 4.23, 95%CI 2.32, 7.74), overjet (RR 2.16, 95%CI 1.28, 3.64), overbite (RR 1.62, 95%CI 1.02, 2.59), crossbite (RR 1.48, 95%CI 1.02, 2.13), and openbite (RR 2.37, 95%CI 1.46, 3.85), when compared to neurotypical individuals. Most estimates showed a small effect size with very low certainty of evidence. CONCLUSION: Autistic individuals show worse oral health status than controls. CLINICAL RELEVANCE: The findings reported herein can help to build health policies to better serve autistic individuals including prevention actions and access to specialized dental care.

Three-dimensional positioning of the maxilla using novel intermediate splints in maxilla-first orthognathic surgery for correction of skeletal class III deformity.

OBJECTIVES: Successful orthognathic surgery requires accurate transfer of the intraoperative surgical plan. This study aimed to (1) evaluate the surgical error of a novel intermediate splint in positioning the maxilla during maxilla-first orthognathic surgery and (2) determine factors influencing surgical error. MATERIALS AND METHODS: This prospective study examined 83 patients who consecutively underwent Le Fort I osteotomy for correction of skeletal class III deformity using a novel intermediate splint and a bilateral sagittal split osteotomy. Surgical error was the outcome variable, measured as the difference in postoperative translational and rotational maxillary position from the virtual plan. Measures included asymmetry, need and amount for mandibular opening during fabrication of intermediate splints, and planned and achieved skeletal movement. RESULTS: Mean errors in translation for vertical, sagittal, and transversal dimensions were 1.0 ± 0.7 mm, 1.0 ± 0.6 mm, and 0.7 ± 0.6 mm, respectively; degrees in rotation for yaw, roll, and pitch were 0.8 ± 0.6, 0.6 ± 0.4, and 1.6 ± 1.1, respectively. The transverse error was smaller than sagittal and vertical errors; error for pitch was larger than roll and yaw (both p < 0.001). Error for sagittal, transverse, and roll positioning was affected by the achieved skeletal movement (roll, p < 0.05; pitch and yaw, p < 0.001). Surgical error of pitch positioning was affected by planned and achieved skeletal movement (both p < 0.001). CONCLUSIONS: Using the novel intermediate splint when performing Le Fort I osteotomy allowed for accurate positioning of the maxilla. CLINICAL RELEVANCE: The novel intermediate splint for maxillary positioning can be reliably used in clinical routines.

East Asian and Southern European craniofacial class III phenotype: two sides of the same coin?

OBJECTIVES: The skeletal class III phenotype is a heterogeneous condition in populations of different ethnicities. This study aimed to analyse the joint and ethnicity-specific clustering of morphological features in skeletal class III patients of Asian and European origins. MATERIALS AND METHODS: This cross-sectional study involved South Korean and Spanish participants who fulfilled the cephalometric, clinical, and ethnic-related selection criteria. Radiographic records were standardised, calibrated, and measured. A total of 54 skeletal variables were selected for varimax factorial analysis (VFA). Subsequently, a cluster analysis (CA) was performed (mixed method: k-means and hierarchical clustering). Method error and precision were assessed using ICC, Student's t-test, and the Dahlberg formula. RESULTS: A total of 285 Korean and Spanish participants with skeletal class III malocclusions were analysed. After performing VFA and CA, the joint sample revealed three global clusters, and ethnicity-specific analysis revealed four Korean and five Spanish clusters. Cluster_1_global was predominantly Spanish (79.2%) and male (83.01%) and was characterised by a predominantly mesobrachycephalic pattern and a larger cranial base, maxilla, and mandible. Cluster_2_global and Cluster_3_global were mainly South Korean (73.9% and 75.6%, respectively) and depicted opposite phenotypes of mandibular projection and craniofacial pattern. CONCLUSIONS: A distinct distribution of Spanish and South Korean participants was observed in the global analysis. Interethnic and interethnic differences were observed, primarily in the cranial base and maxilla size, mandible projection, and craniofacial pattern. CLINICAL RELEVANCE: Accurate phenotyping, reflecting the complexity of skeletal class III phenotype across diverse populations, is critical for improving diagnostic predictability and future personalised treatment protocols.