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Objective: To compare linear distance of glenoid fossa to frontomaxillary nasal suture in skeletal Class-I and II malocclusions. Methods: This cross-sectional study was conducted at the Department of Orthodontics, Altamash Institute of Dental Medicine, Karachi Pakistan. The duration of study was one year from January, 2019 to January, 2020. After taking informed consent from patient and hospital ethical committee a total of 60 patients were included in the study using WHO sample size calculator. Two groups comprising 30 patients each i.e., Skeletal Class-I malocclusion and Skeletal Class-II malocclusion with mandibular retrusion both having normal vertical relationship were included in the study. The cephalometric measurements SNA, SNB, SNMP, FHMP, GF-FMN, CO-GO, CO GN on lateral cephalograms were measured and compared between the two groups. Independent t test was applied and p value ≤ 0.05 was considered as significant. Results: In skeletal Class-I malocclusion the mean linear distance of GF-FMN was 70.2 ± 4.02 mm and in skeletal Class-II malocclusion it was 73.4 ± 4.04 mm (p value .004). Glenoid fossa was 3.2 mm distally placed in patients with Class-II malocclusion. Conclusion: Glenoid fossa position is a diagnostic feature of Class-II malocclusion associated with mandibular retrusion. One of the effective cephalometric measurements to check glenoid fossa position is the distance from the glenoid fossa(GF) to the frontomaxillary nasal suture FMN (GF-FMN). doi: https://doi.org/10.12669/pjms.40.7.8506 How to cite this: Siddiqui S, Ehsan AA, Sakrani H, Samdani SA . Comparison of linear distance of glenoid fossa to frontomaxillary nasal suture in skeletal Class-II and skeletal Class-I malocclusion. Pak J Med Sci. 2024;40(7):---. doi: https://doi.org/10.12669/pjms.40.7.8506 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Skeletal class II and III malocclusions are craniofacial disorders that negatively impact people’s quality of life worldwide. Unfortunately, the growth patterns of skeletal malocclusions and their clinical correction prognoses are difficult to predict largely due to lack of knowledge of their precise etiology. Inspired by the strong inheritance pattern of a specific type of skeletal malocclusion, previous genome-wide association studies (GWAS) were reanalyzed, resulting in the identification of 19 skeletal class II malocclusion-associated and 53 skeletal class III malocclusion-associated genes. Functional enrichment of these genes created a signal pathway atlas in which most of the genes were associated with bone and cartilage growth and development, as expected, while some were characterized by functions related to skeletal muscle maturation and construction. Interestingly, several genes and enriched pathways are involved in both skeletal class II and III malocclusions, indicating the key regulatory effects of these genes and pathways in craniofacial development. There is no doubt that further investigation is necessary to validate these recognized genes’ and pathways’ specific function(s) related to maxillary and mandibular development. In summary, this systematic review provides initial insight on developing novel gene-based treatment strategies for skeletal malocclusions and paves the path for precision medicine where dental care providers can make an accurate prediction of the craniofacial growth of an individual patient based on his/her genetic profile.

The surgical outcomes and stability of patients with skeletal Class II malocclusion determine the success of treatment. Variations in surgical interventions, patient responsiveness, and growth patterns across vertical facial morphologies result in varying treatment outcomes and postoperative stability. This retrospective study recruited 52 adults diagnosed with skeletal Class II malocclusion treated with bimaxillary surgery; these adults were divided into two groups according to their vertical facial patterns. Cone-beam computed tomography images were collected before surgery (T0), after surgery (T1), and after orthodontic treatment (T2). Reconstructed three-dimensional images were used for cephalometric measurements and analysis. From T0 to T1, the Frankfort-mandibular plane angle decreased in the high-angle group but increased in the low-medium-angle group. The mandible advanced 9.02 and 6.21 mm in the high-angle and low-medium-angle groups, respectively. From T1 to T2, significant changes were observed in the anterior mandible horizontal movement of the high-angle group (-1.91 ± 3.63 mm) compared with the low-medium-angle group (-0.57 ± 1.04 mm). There were more patients exhibit clinically significant relapse (> 2 mm) in the high-angle group (44%) than in the low-medium-angle group (20%). The relapse patterns in the two groups were similarly upward and backward. However, the high angle group exhibited greater average postoperative changes. The proportion of patients who exhibited a clinically significant relapse was higher in the high angle group.

ABSTRACT Objective: The aim of the present study was to assess three-dimensional volumetric changes in the temporomandibular joint (TMJ) space after mandibular advancement surgery in skeletal Class II cases with retrognathic mandibles. The null hypothesis for this study posited that there would be no statistical changes after orthognathic surgery. Materials and methods: A retrospective study was conducted on 30 cone-beam computed tomographic (CBCT) records of skeletal Class II patients with retrognathic mandibles who were treated with bilateral sagittal split osteotomy (BSSO) for mandibular advancement of 6-8 mm. Volumetric assessments of joint space were performed pre-operative (T0), one-week post-operative (T1), and 12-month post-operatively (T2). Results: The mean anterior joint space exhibited an increase from 612.37 mm3 at T0 to 876.67 mm3 at T1, followed by a slight reduction to 862.4 mm3 at T2. Conversely, the posterior joint space diminished from 861 mm3 at T0 to 736.27 mm3 at T1 and further to 653.07 mm3 at T2. The medial joint space experienced an increase from 525.83 mm3 at T0 to 850.93 mm3 at T1, before declining to 596.77 mm3 at T2. The lateral joint space showed a decrease from 951 mm3 at T0 to 762 mm3 at T1, subsequently rising to 918.7 mm3 at T2. Strong positive correlation coefficients (approaching 1) were observed in the majority of the T1 and T2 comparisons (p < 0.05). Conclusion: Significant volumetric changes were observed in the TMJ space after mandibular advancement surgery for retrognathism. The changes were maintained even 12 months after surgery, with a slight relapse. RESUMO Objetivo: O objetivo do presente estudo foi avaliar as alterações volumétricas tridimensionais no espaço da articulação temporomandibular (ATM) após cirurgia de avanço mandibular em casos de Classe II esquelética com mandíbulas retrognáticas. A hipótese nula para este estudo foi a de que não haveria alterações estatísticas após a cirurgia ortognática. Material e métodos: Foi realizado um estudo retrospectivo com 30 documentações contendo tomografia computadorizada de feixe cônico (TCFC) de pacientes com Classe II esquelética com mandíbulas retrognáticas, tratados com osteotomia sagital bilateral (BSSO) para avanço mandibular de 6 a 8 mm. Avaliações volumétricas do espaço articular foram realizadas no pré-operatório (T0), uma semana após a cirurgia (T1) e 12 meses após a cirurgia (T2). Resultados: O espaço articular anterior médio apresentou um aumento de 612,37 mm3 em T0 a 876,67 mm3 em T1, seguido de uma ligeira redução para 862,4 mm3 em T2. Por outro lado, o espaço articular posterior diminuiu de 861 mm3 em T0 para 736,27 mm3 em T1 e posteriormente para 653,07 mm3 em T2. O espaço articular medial sofreu um aumento de 525,83 mm3 em T0 para 850,93 mm3 em T1, antes de diminuir para 596,77 mm3 em T2. O espaço articular lateral apresentou diminuição de 951 mm3 em T0 para 762 mm3 em T1, aumentando posteriormente para 918,7 mm3 em T2. Coeficientes de correlação fortemente positivos (aproximando-se de 1) foram observados na maioria das comparações T1 e T2 (p < 0,05). Conclusão: Alterações volumétricas significativas foram observadas no espaço da ATM após cirurgia de avanço mandibular nos casos de retrognatismo. As alterações se mantiveram mesmo 12 meses após a cirurgia, com uma leve recidiva.

BACKGROUND: The volumetric relationship between the tongue and the oral cavity is an important factor in tooth alignment and occlusion. The aim of this study was to evaluate the difference in tongue and airway volume in skeletal Class I and Class II malocclusion. MATERIALS AND METHODS: The CBCT data which comprised of 30 skeletal Class I and 30 skeletal Class II was stored in DICOM format. Tongue volume and airway volume was analyzed with the help of 3D dolphin software. Values obtained were subjected to statistical analysis with help of SPSS. RESULTS: Skeletal Class I pattern had more tongue volume with a mean of 45.32 mm3 than skeletal Class II pattern with mean value of 40.27mm3 with P value of <0.001. Skeletal Class I pattern has more airway volume with a mean of 15058.6 mm3 than patients with Skeletal Class II pattern with mean value of 12458.8mm3 with a P value of 0.003. A P value of 0.001 indicated that there is a strong correlation between the tongue volume and airway volume in both skeletal Class I and skeletal Class II subjects. CONCLUSION: The volume of tongue and airway was greater in skeletal Class I malocclusion compared to skeletal Class II malocclusion. There exists a positive correlation between the tongue volume and airway volume in both the skeletal patterns.

ObjectivesThe location of the maxillary sinus significantly affects the orthodontic treatment, particularly when temporary anchorage devices (TADs) are taking place. The current study aims to evaluate the maxillary sinus size and location in a skeletal class II population.Materials and methodsThe pre-orthodontic treatment CBCT images of the skeletal class II population were selected. The sinus’s volumetric size, height, width, and depth were measured and compared among different skeletal vertical patterns and between genders. In addition, the height and width of the alveolar bone surrounding the maxillary sinus floor were quantified in the same manner.ResultsPatients who displayed a high-angle skeletal pattern had significantly greater maxillary sinus dimensions, shorter vertical distance between the maxillary sinus floor and the alveolar bone crest, and thinner alveolar bone surrounding the maxillary sinus. Meanwhile, the maxillary sinus dimension measurements were positively correlated with the SN-MP angle in both genders but only correlated with ANB angle in females. On the other hand, the vertical distance between the maxillary sinus floor and the alveolar bone crest was negatively correlated with the SN-MP angle in males but the ANB angle in females.ConclusionsIn the skeletal class II population, the high-angle patients faced a higher risk of maxillary sinus perforations by TADs. In addition, gender-related variations were noticed warranting clinical attention, as males have a higher potential for maxillary sinus penetration from TAD placement than females.Clinical relevanceMaxillary posterior alveolar TADs are often prescribed to achieve the distalization of maxillary posterior teeth in class II patients. The current study provided more insight into the “safe zone” for TAD placement related to the maxillary sinus.

Objectives The correlations between the incisal guidance angle (IGA) and occlusal plane angles and temporomandibular joint (TMJ) morphology were investigated in adults with skeletal Class II division II malocclusion. Materials and methods CBCT images of 37 patients were analyzed. It included 19 cases of skeletal Class II division II malocclusion with low angle (study group) and 18 cases of skeletal Class I average angle (control group). The Invivo Dental 5 software was employed to acquire the data of the incisal guidance angle (IGA), occlusal plane angle (FH-OP), anterior occlusal plane angle (FH-AOP) and the TMJ measurement items. Results The results of IGA, FH-AOP angle and FH-OP angle showed the study group > the control group ( P  < 0.05). There were statistically difference in the condylar mediolateral diameters, articular eminence inclination and height, and posterior joint spaces between two groups. No differences were revealed in the condylar anteroposterior diameters, the condylar inclination angle, condylar head width and height, condylar length, glenoid fossa depth and width between two groups. In the study group, IGA showed a moderate correlation with FH-AOP, a weak correlation with FH-OP and condylar mediolateral diameters. Meanwhile, there was a correlation between FH-AOP, FH-OP, and TMJ indicators. Conclusions The IGA was not only related to FH-AOP and FH-OP, but also to the condylar mediolateral diameters. In addition, there was a correlation between the occlusal plane angles and TMJ morphology in skeletal Class II division II low angle malocclusion. Clinical relevance For patients with skeletal Class II division II low angle malocclusion, adjusting the IGA and the occlusal plane angles could improve the esthetic appearance of the anterior teeth, occlusal function, and TMJ morphology.

Background The shape and structure of the temporomandibular joint (TMJ) can be affected by many factors and occlusal factors are considered important factors. Although many scholars have studied the correlation between the occlusal plane (OP) and TMJ morphological characteristics in different types of malocclusion, it is still unclear whether the Balkwill angle and mandibular occlusal plane (MOP) angle affect the TMJ morphology. The aim of this study was to investigate the correlations between the Balkwill angle, the MOP angle and TMJ morphology in adults with skeletal Class II Division II malocclusion using cone-beam computed tomography (CBCT). Methods Seventy adult patients (29 males and 41 females, mean age 23.32 ± 3.22 years) with no symptoms of temporomandibular disorders were divided equally into two groups: skeletal Class II division II low angle-study group (14 males, 21 females, 23.66 ± 3.29 years) and skeletal Class I average angle-control group (15 males, 20 females, 22.98 ± 3.15 years). The Balkwill angle, OP angle (FH-OP), MOP angle (FH-MOP), DPO (vertical distance from the condylar center to the MOP) and TMJ measurement items were measured. Results The mean values of FH-OP and FH-MOP angles were smaller in the study group ( P  < 0.05), while the average values of Balkwill angle and DPO were larger in the study group than in the control group ( P  < 0.05). Significant differences were found in the condylar mediolateral diameters, condylar head width, articular eminence inclination and height, and superior joint space between the two groups. The correlation analysis showed that the Balkwill angle was strongly positively correlated with DPO and negatively correlated with MOP angle. In the control group, the Balkwill angle, MOP angle and DPO had weak correlations with TMJ morphology. However, in the study group, the Balkwill angle, MOP angle and DPO had moderate correlations with TMJ morphology. Conclusions The DPO had a significant impact on TMJ morphology, followed by the MOP angle, and finally the Balkwill angle in skeletal Class II Division II low angle malocclusion.

Background The determining effect of facial hard tissues on soft tissue morphology in orthodontic patients has yet to be explained. The aim of this study was to clarify the hard-soft tissue relationships of the lower 1/3 of the face in skeletal Class II-hyperdivergent patients compared with those in Class I-normodivergent patients using network analysis. Methods Fifty-two adult patients (42 females, 10 males; age, 26.58 ± 5.80 years) were divided into two groups: Group 1, 25 subjects, skeletal Class I normodivergent pattern with straight profile; Group 2, 27 subjects, skeletal Class II hyperdivergent pattern with convex profile. Pretreatment cone-beam computed tomography and three-dimensional facial scans were taken and superimposed, on which landmarks were identified manually, and their coordinate values were used for network analysis. Results (1) In sagittal direction, Group 2 correlations were generally weaker than Group 1. In both the vertical and sagittal directions of Group 1, the most influential hard tissue landmarks to soft tissues were located between the level of cemento-enamel junction of upper teeth and root apex of lower teeth. In Group 2, the hard tissue landmarks with the greatest influence in vertical direction were distributed more forward and downward than in Group 1. (2) In Group 1, all the correlations for vertical-hard tissue to sagittal-soft tissue position and sagittal-hard tissue to vertical-soft tissue position were positive. However, Group 2 correlations between vertical-hard tissue and sagittal-soft tissue positions were mostly negative. Between sagittal-hard tissue and vertical-soft tissue positions, Group 2 correlations were negative for mandible, and were positive for maxilla and teeth. Conclusion Compared with Class I normodivergent patients with straight profile, Class II hyperdivergent patients with convex profile had more variations in soft tissue morphology in sagittal direction. In vertical direction, the most relevant hard tissue landmarks on which soft tissue predictions should be based were distributed more forward and downward in Class II hyperdivergent patients with convex profile. Class II hyperdivergent pattern with convex profile was an imbalanced phenotype concerning sagittal and vertical positions of maxillofacial hard and soft tissues.