Alteração da posição e remodelação dos côndilos mandibulares após cirurgia ortognática : estudo clínico por meio de tomografia computadorizada

• Autor(a) principal: Melo, Marcelo Fernandes Santos
• Data de Publicação: 2015
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da PUC_RS
• Texto Completo: http://tede2.pucrs.br/tede2/handle/tede/6352
• topic: ODONTOLOGIA; ORTODONTIA; CIRURGIA BUCOMAXILOFACIAL; TOMOGRAFIA COMPUTADORIZADA DE FEIXE CÔNICO; CIENCIAS DA SAUDE::ODONTOLOGIA

PURPOSE: The aim of this study was to evaluate three-dimensional displacements and rotational changes of the mandibular condyles in patients with dentofacial deformities underwent bimaxillary orthognathic surgery, through of computerized cone beam tomography (CBCT) and tools and generation and superimposition softwares of virtual 3D models. MATERIALS AND METHODS: The retrospective study used pre CBCT pre- (T0) and postoperative (T1) after 6 months of bimaxillary orthognathic surgery of 20 patients with skeletal malocclusion, equally divided into two groups (10 Class III and 10 Class II of Angle). An automatic superimposition method based on the gray scale of each voxel in the skull base was used to register and render the virtual 3D models of the mandibular condyles. The displacements were visualized and quantified in color-coded maps generated from the calculation of the distances between the closest points of two surfaces (representatives of different times, T0-T1) and by semitransparenct overlays of 3D virtual models pre and post surgical. The changes were quantified on 5 different surfaces of the condyle and were only recorded with values greater than 1.5 mm. To compare the two measurements (T0-T1), because they are paired data, we used the student t test for differences between the two groups Class II and Class III. The level of significance used was p <0.05. Demographic data for the two groups showed a normal distribution by the Kolmogorov-Smirnov test, and its variables were compared using the Student t test for paired samples. RESULTS: The Class III group presented greater displacement outward or bone apposition on the posterior surface and greater displacement inward or bone resorption on the upper surface of the condyle. The Class II group presented greater displacement outward or bone apposition on the upper surface and greater displacement inward or bone resorption on the lateral pole of the condyle. For the Class III group, the predominant rotational displacements were medial roll (10%), medial yaw (15%), pitch down (25%). As for the Class II group, were the predominant medial and lateral roll (5%), medial yaw (20%), pitch up (45%). CONCLUSION: The study confirms that postsurgical adaptations occur after 6 months of bimaxillary orthognathic surgery, and the displacements and rotations condylar larger than 1.5 mm were observed in both groups. The Class II group showed the greatest change condylar, though neither group showed dysfunctional condylar bone remodeling, keeping the postsurgical adaptation relatively stable.