Estabilidade tridimensional a longo prazo da cirurgia de avanço mandibular

• Autor(a) principal: Franco, Alexandre de Albuquerque
• Data de Publicação: 2012
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/14040
• topic: Cone beam computed tomography; Orthognathic surgery; Mandibular advancement; Orthodontic treatment; Three-dimensional image; Tomografia computadorizada de feixe cônico; Cirurgia ortognática; Avanço mandibular; Tratamento ortodôntico; Imagem tridimensional; CNPQ::CIENCIAS DA SAUDE::ODONTOLOGIA

The aim of this observational prospective study was to assess the stability of mandibular advancement surgery using the superimposition of three-dimensional (3D) surface models of 27 patients in order to investigate possible changes caused by bone displacement and/or remodeling in mandibular condyles, rami, menton and soft tissue. The models were obtained from Conic Beam Computed Tomography (CBCT) scans at T1 (preoperative period), T2 (1 year after surgery) and T3 (3 years after surgery). The superimpositions were carried out using as a reference the skull base in the preoperative stage, based on a fully automated scan, which enabled the study of the displacements occurring in the anatomical region of interest (ROI). Fourteen ROIs were determined for evaluation of hard tissue as well as four regions for soft tissues. Moreover, visualization and quantification of the displacements were based on 3D color maps by the contour line (isoline) method. Method reproducibility was evaluated by means of intraclass correlation index, which remained above 0.90 for all ROIs studied. Kruskal Wallis non-parametric test was applied followed by Dunn's post-test to assess changes between T1 and T2, T1 and T3, and T2 and T3 at a significance level of 0.05. Spearman correlations were performed to investigate possible associations between ROI displacements in each study period. Between T1 and T2, the largest condyle displacements occurred in the medial pole (25%, from 2 to 4 mm) and lateral pole (33%, from -4 mm to -2 mm). Regarding the menton, the largest displacements occurred on the inferior border (41%, from 2 to 4 mm / 50%, >4 mm) and anterior surface (12.5%, from 2 to 4 mm / 66.67%, >4 mm .) The posterior border of the left ramus displayed more posterior displacements (50%, from -2 to -4 mm) and on the right side, in the anterior direction (12.5%, from 2 to 4 mm and 12.5%, >4 mm). Between T1 and T3 changes were similar to those mapped between T1 and T2. Between T2 and T3 the largest displacement in the region of the mandibular condyles occurred in the anterior surface on the left side (12.5%, from 2 to 4 mm), right side (8.33%, from -2 to -4 mm) and upper surface (8.33%, from 2 to 4 mm for both sides). In the menton, the largest displacements occurred on the inferior border (16.67%, from 2 to 4 mm) and anterior surface (16.67%, from -2 to -4 mm). Between T1 and T2, and T1 and T3 the soft tissue menton exhibited displacements larger than 2 mm, in conjunction with the hard tissue menton. The lower lip exhibited smaller displacements at the two initial times. Soft tissue accommodation occurred between T2 and T3, indicative of stability. The present study showed that after the first year and the third year, hard and soft tissue displacement and remodeling was on average variable, with the surgical outcome displaying remarkable long-term stability.