Comprehensive three-dimensional positional and morphological assessment of the temporomandibular joint in skeletal Class II patients with mandibular retrognathism in different vertical skeletal patterns.

BACKGROUND: Only a few studies have used 3D cone-beam computed tomography (CBCT) analysis to evaluate the positional and morphological characteristics of the temporomandibular joint (TMJ) in adults with skeletal Class II. No studies have focused on the case of skeletal Class II with mandibular retrognathism in different vertical skeletal patterns. As a result, this study aimed to evaluate and compare the position and morphology of TMJ in adults with skeletal Class II with mandibular retrognathism in different vertical skeletal patterns to the position and morphology of TMJ in the normal Chinese adult population in three dimensions. METHODS: This retrospective study analyzed CBCT images of 80 adult patients. Subjects with skeletal Class II with a normal sagittal position of the maxilla and mandibular retrognathism were classified according to the mandibular angle and facial height ratio into three groups of 20 subjects each: hypodivergent, normodivergent, and hyperdivergent groups, as well as a control group of 20 subjects. The following 3D measurements of TMJ were evaluated: (1) position, parameters, and inclination of the mandibular fossa; (2) position, parameters, and inclination of the mandibular condyle; (3) condyle centralization in their respective mandibular fossae; (4) anterior, posterior, superior, and medial joint spaces; and (5) 3D volumetric measurements of the TMJ spaces. Measurements were statistically analyzed by one-way ANOVA test, followed by Tukey's post hoc test. RESULTS: Significant differences were found in the hyperdivergent and hypodivergent groups compared with the normal group in the vertical and anteroposterior mandibular fossa position, vertical condylar inclination, and condylar width and length. The hyperdivergent group showed the significantly highest condylar inclination with the midsagittal plane; anterior and superior positioning of the condyle; smallest anterior, superior, and medial joint spaces; and largest volumetric total joint space relative to the two other groups. CONCLUSIONS: The condyle-fossa position and morphology differ with various vertical facial patterns in individuals with skeletal Class II mandibular retrognathism. These differences could be considered during TMD diagnosis and orthodontic treatment.

The bridging and normal dimensions of sella turcica in Yemeni individuals.

OBJECTIVE: This study aimed to evaluate and compare sizes, shapes and bridging of the sella turcica (ST) in Yemeni individuals with different skeletal patterns, genders, and ages, and to assess the association between the linear dimension of ST and gender, age, or skeletal patterns. The standard anatomical structure of ST among Yemeni subjects is still unknown and this study can be considered as the first reference regarding ST of Yemeni individuals. MATERIALS AND METHODS: Cephalogram images for 234 subjects (167 females and 67 males) were traced and classified for groups by gender, age, and dentofacial skeletal patterns. Size, shape, and bridging of ST were assessed. Multivariate ANOVA (MANOVA) analysis was used to detect the interaction between gender, age, and skeletal patterns on ST dimensions. RESULTS: The mean values for length, anteroposterior diameter, and depth of ST were 8.02 ± 1.67, 11.37 ± 1.60, and 8.56 ± 1.26 mm, respectively. A significant difference in length of ST between gender and age stages (p < 0.05) was detected while older subjects revealed a greater anteroposterior diameter than younger subjects (p < 0.05). The morphological variations of ST were observed in 55.6% of samples. No significant association between the shape of ST and skeletal patterns (p > 0.05) was found. CONCLUSIONS: ST bridging was highly prevalent in Yemeni subjects (35.9%). Samples showed a higher rate of complete ST bridging in the three skeletal patterns, Class I (17.1%), Class II (18.9%), and Class III (20%). ST dimensions and shape findings in this study can be used as reference standards for further investigation, including the ST area in the Yemeni population.