Despite established links between masticatory dysfunction and cognitive impairment, cognitive function in dentofacial deformity patients remains unexplored. This study represents the first comprehensive cognitive assessment in mandibular prognathism (MP) patients. Brain blood flow (BBF) during chewing was measured using functional near-infrared spectroscopy in MP patients versus normal occlusion controls (NORM, n = 17). Cognitive function using eye-tracking technology (Mirudake) in MP patients (n = 44) was compared to healthy controls (HC, n = 59), with assessing six cognitive domains. MP patients demonstrated significantly reduced chewing-induced BBF in bilateral inferior frontal gyrus compared to NORM. Global cognitive performance showed no significant difference between MP and HC groups (p = 0.48). However, positive correlations existed between BBF and cognitive performance domains including global performance and memory. ROC analysis using pooled bilateral BBF data (n = 88) revealed modest diagnostic potential for cognitive assessment (AUC = 0.657, 95% CI 0.431-0.865). The optimal threshold yielded 62.5% sensitivity, 73.8% specificity, and 72.7% overall accuracy for detecting cognitive impairment. This first systematic cognitive evaluation of MP patients revealed no significant global cognitive impairment despite confirmed reductions in masticatory-induced brain activation. The observed BBF-cognition correlations suggest BBF measurements may have potential utility as an adjunct measure in cognitive screening, warranting further investigation through longitudinal studies examining orthognathic surgery's potential cognitive effects.

Mandibular prognathism (Class III malocclusion) is a craniofacial anomaly characterized by an anteriorly positioned mandible, a concave facial profile and impaired mastication, and appears unusually frequently in Dolang sheep (Ovis aries). We combined clinical phenotyping and three-dimensional (3D) genome profiling to investigate this trait in a Dolang sheep flock. We examined 959 animals using standardized criteria, estimated a local prevalence of 10.3%, and assembled a 200 affected/200 unaffected case-control cohort for genomic analyses. As an exploratory pilot study of 3D genome architecture, we generated in situ Hi-C datasets from mandibular bone of two affected and two control sheep. At 40 kb resolution, global topologically associating domain (TAD) organization and boundary strength were broadly conserved between groups, but sliding-window analyses identified a small number of 1 Mb hotspots where affected animals showed increased TAD-boundary density and strengthened insulation. These UNDER-enriched windows lay near genes with plausible roles in craniofacial development, including ROBO2, COL27A1, VRK2 and a cytokine cluster (IL22/IL26/IFNG with MDM1). Together, our data indicate that mandibular prognathism in Dolang sheep is associated with localized remodeling of chromatin insulation at a restricted set of gene-proximal loci and highlight candidate regions and mechanisms for integration with whole-genome sequencing, association and transcriptomic data.

Spontaneous changes in ramal inclination and their impact on condylar head and joint space in patients with deviated mandibular prognathism: a three-dimensional comparative analysis.

To estimate the prevalence of skeletal anteroposterior malocclusions and their associated components in orthodontic patients living in Puerto Rico. A cross-sectional study was conducted with 50 normodivergent patients (cervical vertebral maturation stages 4-6) from the Orthodontic Graduate Program (2012-2014) of the University of Puerto Rico, Medical Sciences Campus. A calibrated examiner obtained five measurements (Frankfort Horizontal-Sella-Nasion, Sella-Nasion-Gonion-Gnathion, Sella-Nasion-A point, Sella-Nasion-B point, and A point-Nasion-B point) from patients' initial cephalometric x-rays using Dolphin Imaging software, version 11.7, to determine the presence and distribution of skeletal jaw discrepancies. Sex-based differences were explored using the Mann-Whitney and Fisher's exact tests. P < .05 was considered statistically significant. The prevalence of skeletal discrepancies was 78%. The most common skeletal malocclusion was Class II (54%), followed by Class I (34%) and Class III (12%). Class II malocclusions were associated with maxillary prognathism (59%), whereas Class III malocclusions were attributed to mandibular prognathism (83%). Most Class I patients did not present a discrepancy (65%); however, we observed bimaxillary prognathism in 24% of Class I patients, and a low position of Sella was detected in 54% of the sample. No significant sex-based differences were observed in the five cephalometric x-ray measurements (P > .05). A high percentage of patients presented with a skeletal malocclusion. Class II skeletal malocclusions due to maxillary prognathism predominated; no sex-based differences were found for skeletal jaw discrepancies; a low Sella position was frequently observed.

262 - Combined orthodontic and surgical treatment of mandibular prognathism – case report

To evaluate the effects of different subtypes of tonsillar hypertrophy on dentofacial and craniofacial development in children during the mixed dentition stage, and to preliminarily explore associated craniofacial growth trends. A total of 275 children in the mixed dentition stage were retrospectively recruited from two hospitals between August 2023 and July 2024. Tonsillar hypertrophy was assessed using the Brodsky and Baroni methods, and patients were categorized by airway obstruction type: mild (Group A), transverse (Group B), anteroposterior (Group C), or combined (Group D). Anterior occlusion, sagittal skeletal classification, and lateral cephalometric parameters (Jarabak analysis) were recorded and compared across groups. Groups C and D were found to have significantly higher rates of anterior crossbite (16.67% and 21.77%) and skeletal Class III malocclusion (30.95% and 34.01%) compared to Groups A (0.00%, 2.78%) and B (0.00%, 6.00%) (p < 0.05). Subgroup D2 (severe combined obstruction) demonstrated the most pronounced skeletal Class III features, as evidenced by a higher mean SNB angle (78.75° ± 3.92), a lower ANB angle (- 0.03° ± 3.65), and pronounced mandibular prognathism. Both dental and skeletal compensatory changes were most evident in the combined obstruction group, indicating a significant degree of craniofacial imbalance (p < 0.05). Anteroposterior tonsillar hypertrophy is strongly associated with anterior crossbite and skeletal Class III development, primarily through mandibular advancement and rotational growth adaptations. Transverse obstruction has minimal skeletal impact, whereas combined obstruction of multiple directions exacerbates dentoskeletal compensation. These findings highlight the directional influence of upper airway obstruction on craniofacial morphology in growing children and underscore the importance of early interdisciplinary evaluation.

Myhre syndrome is associated with a recognizable pattern of facial differences that develop after early childhood. Patients typically have midface hypoplasia, mandibular prognathism, narrow oral commissures with a short philtrum and thin upper lip vermillion. Other characteristics include deeply set eyes with short palpebral fissures, and small, widely spaced teeth. The aim of this study is to review the concept of prognathism in Myhre syndrome, describe the oral and maxillofacial surgery (OMS) evaluation of three females, and provide some preliminary data to propose more objective guidelines and diagnostic tools for facial evaluation in other patients. In addition to the dysmorphologic examination, maxillofacial imaging is recommended in many patients to evaluate the dentition, midface and mandibular anatomy. An orthopantomogram is useful to visualize the dentition, alveolar portion of the maxilla and the mandible. A lateral cephalogram can assess jaw relationships and allow cephalometric analyses to compare to published norms. With the common characteristics visualized, a checklist has been developed to serve as a guide when evaluating patients. OMS consultation can enhance the care provided by the medical geneticists who usually manage these individuals.

Families studies conducted in different ethnic populations worldwide have helped elucidate the molecular and genetic factors involved in the development of skeletal class III malocclusion. Therefore, the aim of this study is to provide an updated summary. The study followed the JBI Manual for Evidence Synthesis and PRISMA-scR guidelines. PubMed, Scopus, WOS, Google Scholar and DANS databases were explored using specific strategies. Eligible studies included linkage and genome-wide analyses, while association studies, case reports and invivo/in vitro research were excluded. The included studies must have involved at least one family with one or more members exhibiting the skeletal malocclusion phenotypes. An autosomal dominant inheritance pattern with variable penetrance for skeletal class III malocclusions across East Asian, Southeast Asian, Middle Eastern, European and South American populations was identified. In contrast, skeletal class II malocclusions exhibited autosomal dominant and X-linked inheritance patterns, with a higher prevalence in Eastern Mediterranean and South American populations. Key molecular findings include missense mutations in DUSP6 (c.545C>T and c.1094C>T), which affect mandibular prognathism and maxillary deficiency via the FGF/FGFR and MAPK/ERK pathways. Additionally, mutations in ADAMTS1 (c.742I>T), ADAMTS2 (c.3506G>T) and ADAMTSL1 (c.176G>A) impact mandibular growth through aggrecan metabolism and osteogenesis, disrupting bone remodelling via the EGFR/ErbB signalling pathway. This comprehensive review highlights the complex genetic basis of skeletal malocclusions, provides insights into the underlying molecular mechanisms, suggests potential targets for therapeutic intervention, and contributes to our understanding of the genetic architecture of these conditions.

Mandibular prognathism (MP) is the most common type of dentomaxillofacial deformity in East Asian populations. Genetic studies have revealed several MP-associated loci, suggesting that MP could be inherited as familial MP (fMP). However, functional verifications and in-depth mechanistic investigations of these loci are limited. For this study, we recruited 5 fMP families with 17 fMP members and 7 normal members. We first compared the clinical features of the 17 fMP members with 31 nonfamilial MP patients, finding a stronger mandibular overgrowth phenotype in the fMP subjects. Next, we performed whole-exome sequencing analysis with members of the 5 fMP families and singled out a potential fMP-associated pathogenic variant in the CASR gene (namely, rs117375173); the mutation introduces an amino acid substitution (A601G) in exon 7 and confers gain of function in Calcium-Sensing Receptor (CaSR). The rs11735173 variant changes the CaSR protein structure toward a semiactive state, similar to CaSR activated by L-tryptophan (L-Trp). To verify the regulating roles of CASR in mandibular bone growth, we further generated different mouse models with abnormal CaSR function. L-Trp administration effectively activated CaSR/GNAQ expression in vivo and in vitro. The MC3T3-E1 cell line transfected with CaSR with rs117375173 (CaSRA601G) showed increased osteogenic differentiation and collagen synthesis at the transcriptional level. Local injection of L-Trp in the mandible of growing mice significantly increased the mandibular length and BMD, due to activated osteogenic activity and suppressed bone resorption. At the same time, loss of function of CaSR in osteogenic progenitors caused mandibular growth retardation in Gli1-CreER; Casrfl/fl; tdTomatofl/+ mice. In conclusion, our study reveals that abnormal functioning of CaSR affects mandibular bone development and may contribute to the pathogenesis of fMP, providing a theoretical and experimental basis for the early diagnosis of and therapeutic strategies for fMP in clinical practice.

ABSTRACT Purpose To investigate short-term changes in sleep respiratory status and respiratory disturbance index (RDI) pre- and post-orthognathic surgery and determine the period during which morphological changes in the airway and surgical invasion affect postoperative sleep dynamics. Materials and Methods This study enrolled patients with skeletal mandibular prognathism who underwent mandibular ramus sagittal split osteotomy alone (mandible-only group, n = 10) or mandibular and maxillary surgery (two-jaw surgery group, n = 13). Simplified sleep tests were conducted pre-orthognathic surgery (T0) and at 7 (T1), 14 (T2), and 21 (T3) days postoperatively. Correlations between inflammation status at the surgical site before and during the postoperative management period were analysed Results RDI values at T0, T1, T2, and T3 were 3.5 ± 2.1, 5.0 ± 3.1, 4.3 ± 2.7, and 3.2 ± 1.4 in the mandible-only group, and 2.9 ± 2.0, 4.7 ± 2.5, 4.4 ± 2.4, and 2.8 ± 0.9 in the two-jaw surgery group, respectively. In the two-jaw surgery group, the RDI increased significantly between T0 and T1. The RDI in both groups exhibited a declining trend between T1 and T2 and decreased significantly between T2 and T3. C-reactive protein levels and white blood cell counts increased significantly between T0 and T1 and decreased significantly between T1 and T2 in both groups. The airway area was reduced significantly in the mandible-only group. Conclusion Temporary swelling of tissues around the osteotomy site increases the RDI in orthognathic surgery. Airway management for approximately 3 weeks is important until postoperative recovery is complete.

Association between myosin 1H polymorphisms and skeletal–facial profile in Taiwanese patients with mandibular prognathism

A BSTRACT Background: Angle’s Class III malocclusion, characterized by mandibular prognathism and anterior crossbite, presents significant functional and esthetic concerns. Traditionally, fixed braces have been the standard treatment, while clear aligners offer an esthetic and comfortable alternative. The effectiveness of these two modalities in Class III correction remains debated. Objective: This study aimed to compare clinical outcomes, treatment efficiency, patient compliance, and post-treatment stability of clear aligners versus fixed braces in Angle’s Class III malocclusion cases. Methods: A retrospective study was conducted on 50 patients with mild to moderate Class III malocclusion, divided into two groups: aligners ( n = 25) and braces ( n = 25). Pre- and post-treatment lateral cephalograms and dental models were analyzed to evaluate treatment duration, overjet correction, skeletal changes (ANB angle), patient compliance, and post-treatment stability. Statistical analysis was performed using t-tests to compare outcomes. Results: Aligners showed shorter treatment duration (18 ± 3 months vs 22 ± 4 months, P &lt; 0.05) and higher patient compliance (92% vs 75%, P &lt; 0.05) than braces. However, braces resulted in superior skeletal changes (ANB improvement: 1.5° vs 0.8°, P &lt; 0.05). Overjet correction was comparable (3.2 mm vs 3.8 mm, P &gt; 0.05). Aligner patients had a higher need for refinements (10% vs 5%). Conclusion: Clear aligners are effective for dental correction in mild to moderate Class III cases, with better compliance and shorter treatment times. However, fixed braces remain superior in skeletal modifications, making them the preferred choice for more severe cases.

Introduction: Successful orthognathic surgery relies on the accurate diagnosis of facial, skeletal, and dental issues. The purpose of this study is to evaluate and compare Skeletal cephalometric values for orthognathic surgery in Nepalese adults and to compare with Caucasians. Materials and Methods: One hundred adult patients (33 males and 67 females), with an age range of 18-36 years, were selected for the study. The subjects included had skeletal Class I, Average Growth Pattern, no craniofacial abnormality, and no previous history of orthodontic treatment. The Skeletal cephalometric norms for orthognathic surgery analysis values for the Nepalese population were established and compared with those of Caucasians. Results: All the cephalometric parameters, except for facial convexity angle in females, maxillary protrusion in females, mandibular prognathism, chin protrusion, mandibular plane angle, and gonial angle, were less in the Nepalese population than in Caucasians. Conclusion: The cephalometric parameters in the Nepalese adults are significantly different from those of the Caucasian population. These racial differences, which are evident in this study, should be kept in mind while charting out a plan for orthognathic surgery for the Nepalese adults.

BackgroundThis retrospective study aims to compare the postoperative facial profiles of Class III orthognathic surgery patients planned according to the true vertical line (TVL) by comparing their positions with the Barcelona line (BL) reference specifically focusing on Class III patients with maxillary retrognathism and mandibular prognathism.MethodsA retrospective analysis was conducted on 43 skeletal Class III patients undergoing isolated maxillary LeFort I or bimaxillary surgery. Digital planning data were used for preoperative and postoperative (6 months) upper incisor (UI)-BL measurements. Patients were categorized into four groups based on the maxillary incisor position relative to BL: Group 1 (UI > 4 mm behind BL), Group 2 (UI 0–4 mm behind BL), Group 3 (UI 0–4 mm ahead of BL), and Group 4 (UI > 4 mm ahead of BL).ResultsIn total of 43 patients, those with maxillary retrognathia showed significant postoperative transitions towards a more protrusive position, while those with mandibular prognathism exhibited greater stability. (p = 0.001)ConclusionBL is a reliable reference in digital planning for skeletal Class III patients, particularly in cases of maxillary retrusion, leading to outcomes more aligned with contemporary aesthetic standards. These findings support incorporating BL into orthognathic surgery planning to optimize sagittal positioning and facial harmony.Trial registrationBaskent University Institutional Review Board approved this study (D-KA24/16). All participants provided informed consent prior to inclusion.

To compare the effect of postsurgical orthodontic treatment between using clear aligners (CA) or fixed appliances (FA) on the postsurgical stability of patients with mandibular prognathism in the surgery-first approach (SFA). This retrospective study included 54 patients with mandibular prognathism who underwent surgical orthodontic treatment with isolated mandibular setback surgery. The patients were divided into two groups according to the mechanics of postsurgical orthodontic treatment: the CA group included 27 patients treated with clear aligners, and the FA group included 27 patients treated with brackets during postoperative orthodontic treatment. Cone beam computed tomography scans were taken before, immediately after, and at 3, 6, and 12 months postsurgery to assess mandibular relapse. The measurements of postsurgical mandibular relapse including horizontal and vertical positions were compared according to the treatment progress and groups. Total postsurgical mandibular relapse at pogonion was 3.2 mm in the CA group and 2.2 mm in the FA group. Relapse was higher at 3 months postsurgery in both groups, with an average forward movement of 1.4 mm in the CA group and 1.7 mm in the FA group. Relapse in the CA group showed no significant changes over time, indicating persistence beyond the initial period. In contrast, the FA group showed a significant reduction in relapse by 3 months. Overall, the CA group tended to have greater and more persistent relapse than the FA group. Careful consideration of skeletal relapse is needed in the postsurgical management of patients treated with clear aligners in SFA treatment.

Background: Peripherally induced movement disorders are hyperkinetic conditions triggered by peripheral trauma or surgical intervention. Oromandibular dystonia (OMD), a focal dystonia affecting the masticatory and lingual muscles, is the most common peripherally induced movement disorder within the stomatognathic system. However, OMD following orthognathic surgery has rarely been reported.Objective: This study aimed to describe the clinical characteristics, latency, and treatment outcomes of patients who developed OMD after orthognathic surgery in a retrospective single-center case series of six patients.Methods: This retrospective case series included patients presenting with involuntary orofacial movements after orthognathic surgery at Kyoto Medical Center between 2007 and 2025. Inclusion criteria were as follows: onset of OMD within three months following surgery, anatomical correlation, and patient-reported causality. Clinical features, surgical history, latency, and treatment outcomes were analyzed.Results: Six patients (mean age 35.2 years) met the criteria. Four had mandibular prognathism, one had mandibular prognathism with tongue hypertrophy, and one had bimaxillary prognathism with open bite. All underwent sagittal split ramus osteotomy: two had additional Le Fort I osteotomy, one underwent intraoral vertical ramus osteotomy, and one had tongue reduction surgery. OMD subtypes included jaw closing (n = 2), tongue (n = 2), jaw opening (n = 1), and jaw deviation (n = 1). Mean latency to OMD onset was 39.5 days, while the mean delay before referral was 40.3 months. All patients were treated with botulinum toxin injections, resulting in symptomatic improvement. Notably, none of the surgeons initially recognized the association with surgery.Conclusions: OMD may occur as a possible peripherally induced sequela of orthognathic surgery. Although rare, it is likely underdiagnosed. Oral and maxillofacial surgeons should remain aware of this potential complication to facilitate timely diagnosis and appropriate management.

Crouzon syndrome (CS) is a rare genetic condition characterised by craniofacial malformations due to mutations in the FGFR2 gene. This study aimed to evaluate the contributing factors for Angle's Class III malocclusion in patients with CS through cephalometric analysis. Six patients with confirmed CS diagnosis were included in the study. Cephalometric measurements were performed using CT scans and compared to established norms. Pathogenic variants in the FGFR2 gene were identified in all patients. Phenotypic and cephalometric characteristics were assessed in each patient. Results showed consistent craniofacial abnormalities, including midface retrusion, mandibular prognathism, and malocclusion. Cephalometric analysis revealed specific patterns indicating growth deficiency at the posterior base of the skull, maxillary retroposition, and an anterior accommodation of the mandibular condyles in the glenoid fossa. These findings provide valuable insights into the underlying factors contributing to Angle's Class III malocclusion in patients with Crouzon syndrome.

Effect of proximal segment osteotomy level on mandibular angle changes after intraoral vertical ramus osteotomy: a three-dimensional CBCT study.

The present study aimed to investigate changes in cervical lordosis, neck disability, and postural balance through static and dynamic tests in patients with skeletal Class III malocclusion who were treated with bimaxillary orthognathic surgery. In this prospective observational study, 18 patients (mean age 23.3±5.4 years) with maxillary retrusion and mandibular prognathia were treated by bimaxillary orthognathic surgery. Static and dynamic balance tests were recorded with the Kinesthetic Ability Trainer preoperatively (T1) and at least 2 months postoperatively (T2). Cervical lordosis angle (C2-C7) was evaluated with the posterior tangent method on the lateral cephalometric films taken at T1 and T2. Neck disability and pain were assessed through questionnaires at both time points. The median follow-up time was 5.8 months. The mean maxillary advancement was 4.0 mm at point A (p=0.001). The mean mandibular setback was 2.4 mm at point B (p=0.166). An 8.4 mm maxillomandibular correction was observed according to the Wits appraisal (p=0.001). Static and dynamic balance tests, cervical lordosis angle, neck disability, and pain revealed no significant change between T1 and T2. No statistically significant correlation was observed between surgical movements and changes in the cervical lordosis angle. Orthognathic surgical correction of skeletal Class III malocclusion, -primarily through maxillary advancement with less mandibular setback- did not lead to significant changes in cervical lordosis, neck disability, or postural balance as assessed through static and dynamic tests.

Bilateral sagittal split ramus osteotomy (BSSRO) is the gold-standard surgical treatment for mandibular prognathism and facial symmetry restoration in class III malocclusion. However, it remains unclear whether asymmetric and symmetric mandibles exhibit differential relapse patterns that impact both functional stability and aesthetic outcomes. This study aims to compare intraoperative displacement and postoperative skeletal relapse between asymmetric and symmetric mandibles following BSSRO. This retrospective cohort study analyzed class III malocclusion patients who underwent BSSRO between January 2018 and December 2023. Three-dimensional CBCT datasets were obtained at three time points: preoperative (T0), immediately postoperative (T1), and at least 6 months postoperative (T2). Translational and rotational changes in mandibular segments (distal and proximal) were quantitatively assessed during surgical correction (T0-T1) and relapse (T1-T2). Intraoperatively, the asymmetric group (AG) exhibited greater displacement toward the non-deviated side of the distal segment (P=0.001) and movement of the non-deviated proximal segment toward the deviated side (P=0.044) compared to the symmetric group (SG). Rotational analysis revealed increased clockwise yaw in AG's distal segment (P=0.009) and enhanced clockwise roll in the non-deviated proximal segment (P=0.021). Postoperatively, AG demonstrated significant relapse toward the deviated side in both proximal segments (non-deviated side: P<0.001; deviated side: P=0.027), counterclockwise yaw in the distal segment (P=0.020), and a counterclockwise rolling tendency in the non-deviated proximal segment (P=0.050). Asymmetric and symmetric mandibles exhibit distinct relapse patterns following BSSRO, involving both translational and rotational movements across all segments. These findings highlight the importance of individualized surgical planning and postoperative management in asymmetric cases. Further validation through prospective multicenter studies with long-term follow-up is recommended. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .