RESUMO
PURPOSE: To compare characteristics of temporomandibular joint and related structures according to gender and Angle â , â ¡1, â ¡2 and â ¢ class. METHODS: Cone-beam CT (CBCT) was performed in 123 patients with malocclusion, and three-dimensional reconstruction was performed with Mimics 19.0 software. The anterior, upper, and posterior spaces of temporomandibular joint, width and depth of acetabulum, height and horizontal angle of condyle, radius of condyle, and anteroposterior and long-axis diameter of condyle were analysed on sagittal plane. The position of condyle in the joint fossa was analyzed using Pullinger methods. SPSS 22.0 software package was used for statistical analysis. RESULTS: Significant differences were found in the long axis and radius of the condyles between Class â and â ¢, Class â and â ¡1, respectively (P<0.05). The widest acetabulum was observed in Class â ¢, followed by Class â , â ¡1, and â ¡2. Moreover, the deepest acetabulum was found in Class â ¡2, followed by Class â ¡1, â , and â ¢. No significant differences were detected in the left and right condyle-related structures among different temporomandibular articulation. In addition, the anterior articular space was significantly larger in Class â patients, compared with Class â ¡2 patients. CONCLUSIONS: There are significant differences in condylar morphology, joint space, joint fossa morphology and condylar position between different Angle classifications.
Assuntos
Má Oclusão Classe III de Angle , Má Oclusão Classe II de Angle , Má Oclusão , Tomografia Computadorizada de Feixe Cônico , Dentição Permanente , Humanos , Má Oclusão Classe II de Angle/diagnóstico por imagem , Má Oclusão Classe III de Angle/diagnóstico por imagem , Côndilo Mandibular/diagnóstico por imagem , Articulação TemporomandibularRESUMO
PURPOSE: To establish an in vitro mechanical stimulation model of cranial base synchondrosis chondrocytes, and to study the effect of cyclic tensile stress on the main extracellular matrix of rat cranial base synchondrosis. METHODS: Cyclic tensile stress was imposed to the second passage of cranial base synchondrosis chondrocytes for 3, 6, 12 and 24 hours respectively by using a Flexcell Strain Unit-5000T(10% surface elongation, 1 Hz). After mechanical loading, the total RNA of the cells harvested from six-well BioFlex was extracted. Real-time quantitative RT-PCR was performed to quantify the mRNA levels of type â ¡ collagen and Sox9. The data were analyzed with SPSS 17.0 software package. RESULTS: Compared with the control group(0 h group), the mRNA expression of type â ¡ collagen was decreased after 3 hours of loading, but not statistically significant; While the expression of Sox9 decreased significantly (P<0.05). In the 6 h group, the expression of Col-â ¡ and Sox9 decreased significantly (P<0.01 and 0.05, respectively). The expression of Col-â ¡ and Sox9 increased in the 12 h group. The 24 h group showed significant increase in both type â ¡ collagen and Sox9 (P<0.05). CONCLUSIONS: The results illustrate that cyclic tensile stress can affect the synthesis of the main extracellular matrix of cranial base synchondrosis in vitro. Expression of type â ¡ collagen and Sox9 can be inhibited during early stage of mechanical loading. However, when loading time extends, the mechanical stimuli greatly promotes the expression of type â ¡ collagen and Sox9. The reaction of Sox9 in this in vitro mechanical stimulation model happens earlier than that of type â ¡ collagen.