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Abstract Temporomandibular joint osteoarthritis (TMJOA) is a common degenerative disease that causes chronic pain and joint dysfunction. However, the current understanding of TMJOA pathogenesis is limited and necessitates further research. Animal models are crucial for investigating TMJOA due to the scarcity of clinical samples. Class II malocclusion is an occlusal type highly associated with TMJOA, but it currently lacks appropriate animal models for simulating this malocclusion in research. Therefore, this study develops a new malocclusion model using a unilateral anterior large overjet (UALO) dental device to cause Class II malocclusion characteristics and TMJOA-like pathological alterations in rats. By inducing a posteriorly positioned condyle, the UALO device effectively results in cartilage degradation, subchondral bone loss, condylar volume reduction, and mandibular retrusion. Furthermore, RNA sequencing of condylar cartilages revealed that the oxidative stress of chondrocytes was elevated under the UALO-triggered abnormal mechanical stress. Disruption of antioxidant systems and mitochondrial dysfunction are involved in cartilage degeneration. The current study provides a novel and reliable rat model suitable for TMJOA research and offers insights into the disease’s potential mechanistic pathways and molecular targets, contributing to a deeper understanding of TMJOA.

Abstract Background A correct diagnosis of patients with an Angle Class II malocclusion is needed to guide treatment decisions toward the contributing jaw and to achieve better treatment outcomes. The aim of the study is to evaluate the diagnostic potential of the Fränkel manoeuvre (FM) for detecting the components determining sagittal discrepancy in Angle Class II division 1. Materials and methods Anonymous questionnaires containing photographs were distributed totwo groups: general practitioner (GP) dentists and orthodontists. The level of the patient’s profile aesthetics before (T0) and after (T1) the manoeuvre was determined using a 100 mm visual analog scale, and the ‘profile improvement’ score was defined as T1 minus T0. The diagnostic ability of the FM was calculated by comparison with lateral cephalometry as a reference standard using receiver operating characteristic (ROC) curve analysis. Results A total of 102 respondents participated in the survey; 40 were orthodontists, and 62 were GP dentists. According to the post-FM images, the “profile improvement” score (T1-T0) was significantly greater in patients with mandibular retrusion than in those with maxillary protrusion (p

Background: A correct diagnosis of patients with an Angle Class II malocclusion is needed to guide treatment decisions toward the contributing jaw and to achieve better treatment outcomes. The aim of the study is to evaluate the diagnostic potential of the Fränkel manoeuvre (FM) for detecting the components determining sagittal discrepancy in Angle Class II division 1. Materials and methods: Anonymous questionnaires containing photographs were distributed totwo groups: general practitioner (GP) dentists and orthodontists. The level of the patient's profile aesthetics before (T0) and after (T1) the manoeuvre was determined using a 100 mm visual analog scale, and the 'profile improvement' score was defined as T1 minus T0. The diagnostic ability of the FM was calculated by comparison with lateral cephalometry as a reference standard using receiver operating characteristic (ROC) curve analysis. Results: A total of 102 respondents participated in the survey; 40 were orthodontists, and 62 were GP dentists. According to the post-FM images, the "profile improvement" score (T1-T0) was significantly greater in patients with mandibular retrusion than in those with maxillary protrusion (p < 0.05). The predictive power of FM, coinciding with the area under the ROC curve, was 0.62 for GPs and 0.78 for orthodontists. Conclusions: The FM method is a useful and accurate tool for diagnosing skeletal Angle Class II malocclusion etiology (mandibular retrusion or maxillary protrusion), especially when used by orthodontists. [ABSTRACT FROM AUTHOR]

This case report describes the successful treatment of an 11-year-old girl with skeletal Class II malocclusion, mandibular retrognathism and anterior crowding using clear aligners. The treatment strategy included extraction of the four first premolars to resolve dental crowding, the use of Class II elastics to achieve bite jumping and canine and molar Class I occlusion, and delicate vertical control to improve the patient’s lateral profile. After 4 years of treatment, all the treatment objectives, including dental alignment, mandibular repositioning and improvement of the lateral profile, were achieved successfully. The present case demonstrates the effectiveness of and advantages offered by clear aligners and Class II elastics as an alternative treatment option for adolescent patients with Class II malocclusion and severe crowding. [ABSTRACT FROM AUTHOR]

Objective: This study examined the glenoid fossa in Class II and Class III malocclusions with mandibular retrusion and protrusion. Materials and Methods: A retrospective investigation examined 60 Class II and 60 Class III cephalometric radiographs. Cephalometric landmarks and glenoid fossa measurements were taken. Statistical analysis contrasted the two malocclusion groups' glenoid fossas. Results: Class II malocclusion had a much lower mean Sella–Nasion–Condylion (SNCd) angle (glenoid fossa sagittal position) than Class III (14.6° ± 1.9). Class II malocclusion had a lower mean Sella–Nasion–Gonion (SNGo) angle (32.5° ± 4.3) than Class III (36.2° ± 3.9). The SNCd angle and SNGo angle in both groups demonstrated a negative correlation, demonstrating a relationship between the glenoid fossa and the mandibular sagittal axis. Conclusion: The glenoid fossa location differs significantly between Class II malocclusion with mandibular retrusion and Class III with protrusion. Class II malocclusion has a posterior glenoid fossa, while Class III has a less posterior one. Understanding these links may help patients receive more personalized treatment.

The 6- piece mandibular osteotomies was described in 1988 by Obwegeser H.L.; mobilizations interested 4 segments and the continuity between the left and right bodies was preserved. This piece of work aims to present a single surgical session for treating an adult with severe developmental deficiency of the mandible. The vertical height and projection of the patient middle third of the face and the SNA angle were within normal ranges contrasting to the 65° SNB. The 5-h procedures involved, in consequence, an incisor-canine subapical setback, an extended BSSO advancement and a double-stepped augmentation genioplasty. The lower third of the face was advanced by 25 mm. Combining mandibular osteotomies may safely save time and expenses.

Objective: This study examined the glenoid fossa in Class II and Class III malocclusions with mandibular retrusion and protrusion. Materials and Methods: A retrospective investigation examined 60 Class II and 60 Class III cephalometric radiographs. Cephalometric landmarks and glenoid fossa measurements were taken. Statistical analysis contrasted the two malocclusion groups' glenoid fossas. Results: Class II malocclusion had a much lower mean Sella–Nasion–Condylion (SNCd) angle (glenoid fossa sagittal position) than Class III (14.6° ± 1.9). Class II malocclusion had a lower mean Sella–Nasion–Gonion (SNGo) angle (32.5° ± 4.3) than Class III (36.2° ± 3.9). The SNCd angle and SNGo angle in both groups demonstrated a negative correlation, demonstrating a relationship between the glenoid fossa and the mandibular sagittal axis. Conclusion: The glenoid fossa location differs significantly between Class II malocclusion with mandibular retrusion and Class III with protrusion. Class II malocclusion has a posterior glenoid fossa, while Class III has a less posterior one. Understanding these links may help patients receive more personalized treatment. [ABSTRACT FROM AUTHOR]

The aim of this study was to clarify the relationship between the severity of condylar osteoarthritis (OA) and skeletal mandibular retrusion. Three-dimensional cephalometric characteristics of skeletal mandibular retrusion were analysed using computed tomography scans from 15 patients with OA and 15 without OA. Mandibular, dental, and condylar-related factors were evaluated. Severity was scored by counting findings of cysts, erosion, atrophy, osteophytes, and sclerosis (score of 1 for the presence of each). The OA group was further divided into mild and moderate OA according to the total severity score of both condyles. The mean condylar volume was significantly lower in OA (851.1 mm 3 ) than in non-OA (1151.3 mm 3 ) (P < 0.001). A decrease in volume was significantly correlated with the number of radiographic OA findings (P = 0.012). Findings seen in mild OA were mostly cysts and erosion, while all findings were identified in moderate OA. The measured factors did not differ significantly between the mild OA and non-OA groups, whereas many mandible-related factors differed significantly between the moderate OA and non-OA groups. A significantly lower volume of the condyle was observed in moderate OA compared to non-OA (P < 0.001), suggesting that the appearance of atrophy, osteophytes, and sclerosis worsened OA from mild to moderate, and correspondingly, mandibular retrusion became apparent., Competing Interests: Declaration of Competing Interest The authors declare that they have no conflict of interest., (Copyright © 2025 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: This study aimed to compare the minimum axial (min Ax) area and the volumes of the nasopharyngeal (NP) and oropharyngeal (OP) airways of patients with Class II malocclusion with different sagittal positions of the mandible and maxilla and patients with Class I malocclusion with normal jaw positions. Methods: Airway areas and volumes of 51 patients with Class I malocclusion with normal maxillary and mandibular positions (0 < ANB < 4, 84 > SNA > 80, and 82 > SNB > 78) were compared with 21 patients with Class II malocclusion with normal maxillary and retrognathic mandibular positions (ANB>4, 84>SNA>80, and SNB4, SNA>84, and 82>SNB>78). Results: In the comparison of airway measurements between Class I and Class II groups, significant differences were found in the OP airway volume, total airway volume, and minimum OP axial area. Patients with Class II mandibular retrusion had smaller OP airway volume. The total airway volume and min Ax area were significantly lower in the Class II mandibular retrusion group than in other groups. Conclusions: The sagittal position of the jaws affects the OP airway volume and the minimum axial airway area, but not the NP airway volume.

Background: This study aimed to compare the minimum axial (min Ax) area and the volumes of the nasopharyngeal (NP) and oropharyngeal (OP) airways of patients with Class II malocclusion with different sagittal positions of the mandible and maxilla and patients with Class I malocclusion with normal jaw positions. Methods: Airway areas and volumes of 51 patients with Class I malocclusion with normal maxillary and mandibular positions (0 < ANB < 4, 84 > SNA > 80, and 82 > SNB > 78) were compared with 21 patients with Class II malocclusion with normal maxillary and retrognathic mandibular positions (ANB>4, 84>SNA>80, and SNB<78) and 21 patients with Class II malocclusion with prognathic maxillary and normal mandibular positions (ANB>4, SNA>84, and 82>SNB>78). Results: In the comparison of airway measurements between Class I and Class II groups, significant differences were found in the OP airway volume, total airway volume, and minimum OP axial area. Patients with Class II mandibular retrusion had smaller OP airway volume. The total airway volume and min Ax area were significantly lower in the Class II mandibular retrusion group than in other groups. Conclusions: The sagittal position of the jaws affects the OP airway volume and the minimum axial airway area, but not the NP airway volume. [ABSTRACT FROM AUTHOR]

Objective To comapre the clinical effect of invisible MA and double plate appliance in the treatment of children with early skeletal Class II mandibular retrusion malocclusion. Methods We selected 30 children with skeletal Class II mandibular retrusion malocclusion, with an average age of 10.5 years, divided them into invisible MA appliance correction group (group A) and twin-block correction group (group B), 15 cases in each group. The changes of jaw and teeth before (T0) and after (T1) treatment were measured and analyzed. Results Bone indexes：after treatment, there were statistically significant increases in SNB Angle, decrease in ANB Angle, decrease in Wits value, and increase in Pg/OLP of mandibular position in both groups (P < 0.05), while there was no statistically significant difference between the two groups (P > 0.05). After correction, the anterior height ratio of s-Go/N-ME in both groups decreased, while the mandibular plane Angle SN/MP, the anterior lower height ratio and the anterior lower height ratio of ANS/N-ME in both groups increased (P < 0.05), and the differences between the two groups were statistically significant (P < 0.05). Dental properties: U1-SN of the upper incisor decreased, l1-MP of the lower incisor increased, coverage improved, and molar relationship improved after treatment in both groups, all of which were statistically significant (P < 0.05). Only l1-MP Angle was significantly different between the two groups (P < 0.05). Pancherz analysis was used to conclude that the bone effect of group A was greater than that of group B. Conclusions The two kinds of orthodontics can effectively promote the development of mandible and improve the intersagittal deformity of mandible. After the orthodontics, the mandible will rotate clockwise, but the invisible orthodontics rotate less than the double plate orthodontics. The invisible orthodontic device MA can control the axial inclination of the anterior teeth better, and the loss of the anterior anchorage is less, so the orthodontic treatment can obtain better bone effect. [ABSTRACT FROM AUTHOR]

The purpose of this study was to analyze the quantitative correlation between condylar resorption and skeletal relapse after mandibular advancement surgery. Skeletal Class II malocclusion patients who underwent bilateral sagittal split ramus osteotomy (BSSRO) were included. Three-dimensional reconstruction was based on one-week and one-year post-operative CT scans. The condylar morphological alterations were assessed by anterior-posterior, medial-lateral diameter and condylar height. The mandibular relapse was calculated by the positional changes of pogonion, menton, gonions, gnathion and mental foramens. All data were measured by MIMICS and analyzed by SPSS software; significance was set at p<0.05. 31 patients (62 condyles) were enrolled into this study. 28 of 62 condyles showed resorption beyond 1 mm on condylar height and 15 were beyond 2 mm. Positional changes of chin, mental foramens and gonion were respectively 1.57 ± 2.36 mm, 1.31 ± 1.23 mm and 1.42 ± 1.02 mm. 21 of 31 patients experienced mandibular relapse less than 1 mm but additional 4 patients showing relapse more than 2 mm. Correlation with moderate intensity could be observed between condylar height alteration and post-operative mandibular displacement more than 1 mm (p = 0.035). The resorption degree of condylar height can be regarded as a useful parameter for evaluating post-operative skeletal relapse. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare the condylar positional changes after bilateral sagittal split ramus osteotomy (BSSRO) in patients with mandibular retrusion and those with mandibular prognathism. We also studied the correlation between the degree of matching of the condyle and fossa, and condylar displacement. Thirty patients with mandibular retrusion (n = 11) or mandibular prognathism (n = 19) who underwent BSSRO were included. The condylar position was assessed from spiral computed tomographic (CT) scans taken preoperatively, during the first postoperative week, and at least 6 months postoperatively. All data were measured by MIMICS 17.0 and analyzed by Student's t test and Pearson's correlation analysis. The size of the condyles of patients with mandibular retrusion was significantly less than those of patients with mandibular prognathism (491.5 (172.8) compared with 823.2 (212.0) mm3). The size of the glenoid fossa in those with mandibular retrusion (599.6 (110.4) mm3) and those with prognathism (597.6 (151.6) mm3) did not seem to differ. Postoperatively the condyles moved outwards, backwards, and downwards in both groups of patients. Correlation analysis between the condyle:fossa volume ratio and the condylar positional changes showed that a large condyle:fossa volume ratio correlated with the smaller positional changes in the condyle. The condylar position changed immediately after mandibular advancement and setback, and persisted in the long term. Larger condyles tended to have fewer positional changes. [ABSTRACT FROM AUTHOR]

Introduction: In orthognathic surgery, we often experience that model mounting by the occlusal bite record taken at centric relation under the conscious condition in the sitting position does not always correctly replicate the actual maxilla–mandibular relationship under general anesthesia. Mandible often moves backward further in the latter condition. The present study was carried out to investigate the degree of extra retrusion of the mandible under general anesthesia and to determine the characteristics in each of the three original skeletal class patterns in a Japanese population. Patients and methods: Fifty patients with jaw deformities (14 males and 36 females) were enrolled in this prospective study, their ages ranging from 16 to 49 years. The occlusal bite record at the incisor region obtained from a mounted articulator was compared with the records from the oral cavity of the patient under general anesthesia before surgery. Results: Retrusion in the supine position under general anesthesia was observed in all skeletal classes, and it was significantly greater in skeletal Class II, compared to skeletal Class I and Class III. Conclusion: This study clearly revealed the difference among three different skeletal classes, and the mandible in the skeletal Class II moved backward significantly compared to other classes. [ABSTRACT FROM AUTHOR]

Mandibular deviation and rotation following mandibulectomy can significantly impact oral function and quality of life. The postoperative course of a 57-year-old patient who underwent mandibulectomy for oral cancer and findings over 11 years of follow-up observation to monitor changes in the mandibular position are described here. Based on the observations, it is important to raise awareness regarding the necessity of continued monitoring of mandible position and regular adjustments of prostheses for patients who have undergone mandibulectomy.

Objective: To assess the dental class occlusion and lateral cephalometry of children with conservatively treated Pierre Robin sequence (PRS) and to identify associations between these findings and prepalatoplasty cleft palate measurements.Study Design: Retrospective cohort study.Subjects and Methods: Among 22 patients with PRS, the following data were prospectively collected: demographics and preoperative cleft palate measurements. After patients reached age 6 years, an orthodontist assessed dental occlusion class and performed a lateral cephalometric analysis. PRS cephalometric data were compared with reference population values. Bivariate logistic regression was used to test the association with malocclusion class. Results are presented as odds ratios with 95% profile likelihood confidence intervals. The association between cleft measurements and cephalometric parameters was tested with Spearman's correlation ( rs).Results: All 22 patients had bimaxillary hypoplasia and were prone to hyperdivergency, with a 41% rate of dental class III malocclusion. An increased anterior growth of the still retrusive mandible mostly accounts for the occurrence of the class III malocclusion in PRS (class II SNB = 74.3° vs class III SNB = 77.6°, P = .04). A larger cleft at the time of the cleft repair (mean, 11 months) was associated with increased mandibular retrusion (smaller SNB angle, rs = -0.5, P = .02).Conclusions: The 41% rate of class III malocclusion among these conservatively treated patients needs to be considered in the choice of the initial airway approach. The future impact of early mandibular advancement will have to be determined. [ABSTRACT FROM AUTHOR]

Objective: Purpose of this prospective study was to evaluate the skeletal and dentoalveolar effects of a fixed functional appliance, the Austro Repositioner, in dolicho- and brachyfacial skeletal Class II patients.Material and methods: In all, 20 dolicho- and 25 brachyfacial consecutive patients treated with the Austro Repositioner were compared with untreated controls (20 dolicho- and 20 brachyfacial patients) with the same initial dentoskeletal features. Lateral cephalograms were acquired before and 1.0±0.2 year after therapy.Results: Significant improvements in skeletal Class II relationships were observed in both groups. The ANB angle decreased (3.56° in dolicho- and 3.13° in brachyfacial patients, P < 0.001) due to changes localized exclusively in the mandible, the SNB angle increased to 3.20° in dolicho- and 3.02° in brachyfacial patients, and the total mandibular length (Co-Pg) increased to 6.47 mm in dolicho- and 5.78 mm in brachyfacial patients (P < 0.001). A favorable guidance of vertical pattern was also achieved in both groups, and no significant changes were observed in the upper and lower incisors in both groups.Conclusions: The Austro Repositioner was effective for short-term treatment of skeletal Class II malocclusion resulting from the retrusion of the mandible in both dolicho- and brachyfacial patients. [ABSTRACT FROM AUTHOR]

Objective： To research the clinical effects of Twin-block appliance on the hard tissue structure and temporomandibular joint of the patients with skeletal mandibular retrusion at the peak stage of development. Methods： 20 patients with a skeletal Angle ClassⅡ mandibular retrusion were treated with Twin-block appliance. The mandibular changes were analyzed including the length and height of mandible with reference to the lateral cephalograms, and temporomandibular joint changes were evaluated by means of magnetic resonance imaging before and after the treatment. Results： After treatment,there was significant increase in the whole length of mandible（Co-Gn）, the height of mandible（Co-Go） and the length of mandibular body（Go-Gn） compared with before treatment（P〈0.05）.Significant changes took place in growth of height of condyle（P〈0.05）. No significant differences were found about the width of condyle and parameters of joint space（P〉0.05）. Conclusions： Twin-block appliance has a significant bone orthopedic effect on mandibular retrusion patients at the peak stage of development, stimulate adaptive remodeling of condylar. [ABSTRACT FROM AUTHOR]

Introduction: Posterior transverse discrepancy as seen in some cases of Class II Division 1 malocclusion in mixed dentition period can be related to typical skeletofacial characteristics. These features when studied early in the mixed dentition period give a clear view of the desired appropriate treatment plan in a particular case. Aim: The purpose of this study was to establish a simple method to determine the posterior (intermolar) transverse discrepancy and craniofacial skeletal features between the dental arches during the mixed dentition in a sample of Class II Division 1 patients to provide diagnostic and therapeutic guidance in the early approach. Materials and Methods: A sample of 60 Class II Division 1 patients in mixed dention that were divided into 30 Class II Division 1 patients with posterior transverse interarch discrepancy {Class II (I) PTID group} and 30 Class II Division 1 patients without posterior transverse interarch discrepancy {Class II (I) NPTID group}. Thirty Class I subjects in mixed dentition were included as control. Results: The skeletal features of the Class II group without PTID are those of the skeletal Class II associated with ‘anatomic’ mandibular retrusion (due to a micrognathic mandible) and those of the Class II group with PTID as skeletal Class II associated with only a ‘functional’ mandibular retrusion (due to a posteriorly displaced mandible of normal size). Conclusion: This study confirmed the role of occlusion in the control of maxillomandibular skeletal relationships.The treatment strategies could be planned on the basis of the transverse component of Class II Division 1 groups in the mixed dentition period.

This report describes the treatment of severe skeletal Class II malocclusion in a young woman with a gummy smile and pronounced lower anterior facial height. Overjet and overbite were +12.0 mm and -1.0 mm, respectively. Cephalometric analysis revealed inferior positioning of the maxilla and severe mandibular retrusion with clockwise rotation. Both the upper and lower anterior teeth showed labial inclination. Based on a diagnosis of a skeletal Class II high angle with mandibular retrusion and a gummy smile, double-jaw orthognathic surgeries for upper and lower premolar extraction were chosen to gain ideal occlusion and an improvement in the esthetic facial profile. Le Fort I osteotomy was performed to move the anterior and posterior teeth upward by 4.0 mm and achieve mandibular counterclockwise rotation. Short lingual sagittal split ramus osteotomy was performed to move the mandible forward by 3.0 mm. As a result, normal overjet and overbite were achieved together with a straight profile and a good smile. After surgery, electromyographic evaluation of anterior temporal muscle activity showed an improvement in the percentage overlapping coefficient value (a symmetric index of bilateral muscle activity) from 28.1% to 63.2% compared to at pre-treatment. The pattern of jaw movement also showed an improvement. These results suggest that orthognathic surgery in skeletal Class II cases can improve not only malocclusion and the skeletal relationship of the jaws, but also masticatory function and jaw movement.

Summary The famous castrato singer Carlo Broschi, better known as Farinelli (1705–1782), was exhumed by our research group in July 2006 to study his skeletal remains and reconstruct his osteobiography. He was castrated before puberty to preserve his high voice into adulthood. The osteological study has revealed several skeletal features probably related to the effects of castration ( Hyperostosis frontalis interna , long limb bones, persistence of epiphyseal lines, osteoporosis) ( Belcastro et al., 2011 ). Here we present the study of the teeth and maxilla–mandibular region using classic and tomographic morphological methods. Considering the subject's age and the period during which he lived, his oral health conditions were good. On the basis of the very pronounced anomalous vestibular buccal wear, a overbite visualized by 3D reconstruction, was hypothesized. This facial disharmony is of particular interest when considering Farinelli's extraordinary singing qualities and stage presence. [ABSTRACT FROM AUTHOR]

Objective: To assess the net dentofacial effects of the fixed lingual mandibular growth modificator (FLMGM). Materials and Methods: The study sample comprised 38 patients with Class 11/1 malocclusion and retrognathic mandible. All were in the pubertal growth spurt. Whereas FLMGM was applied to the treatment group (n = 21, mean age = 13.2 years), no treatment was performed on the control group (n = 17, mean age = 12.5 years). Skeletal and dentoalveolar changes were assessed on digital lateral cephalograms obtained at the beginning and end of the treatment/observation period of 8 months. Paired and independent f-tests were used to assess the differences within and between groups. Results: Maxillary growth was not affected by FLMGM treatment, which resulted in a significant overjet reduction of 4.1 mm, an increase in total mandibular length (Co-Gn) of 2.3 mm, chin advancement of 1.6°, and upper incisor retroclination of 4.0°. A reduction of 2.4° in ANB was largely due to an increase of 1.8° in SNB. Favorably, the lower incisors were obviously retroclined by 4.5°. The changes in the vertical skeletal relationships were negligible. Conclusion: FLMGM was effective in treating growing Class 11/1 patients and produced favorable dentofacial effects, with the matched untreated sample showing minimal changes. Lower incisor retroclination was a benefit of FLMGM treatment. [ABSTRACT FROM AUTHOR]

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