Alterações esqueléticas associadas à expansão rápida de maxila assistida cirurgicamente: análise por sobreposição de modelos tomográficos
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Data
2019-01-15
Autores
Oliveira, Talles Fernando Medeiros de [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A expansão rápida de maxila assistida cirurgicamente (ERMAC) é uma técnica amplamente aceita para o tratamento das deficiências transversais de maxila em pacientes adultos. Este estudo avaliou as alterações esqueléticas tridimensionais em maxila e mandíbula decorrentes da ERMAC. Um estudo retrospectivo foi realizado com as imagens tomográficas de 20 pacientes adultos submetidos a ERMAC. O método de sobreposição tridimensional da base do crânio e análise de correspondência de forma foram utilizados nas tomografias computadorizadas de feixe cônico (TCFC) obtidas antes da ERMAC (T1) e seis meses após expansão (T2) para avaliar as alterações esqueléticas associadas a ERMAC, a assimetria ocorrida durante a expansão e as alterações de posicionamento mandibular após a ERMAC. A sobreposição por semitransparência e o mapa de cores e vetores foram utilizados para avaliar qualitativamente as alterações esqueléticas após a ERMAC. Oito regiões de interesse na maxila e cinco regiões de interesse na mandibula foram selecionadas para quantificação das diferenças entre os tempos T1 e T2. Testes não paramétricos foram utilizados na análise estatística. As regiões maxilares analisadas apresentaram aumento significativo após a ERMAC, com maiores deslocamentos observados na região de ectocanino e ectomolar. Foi observado assimetria na expansão em até 40% dos pacientes quando avaliado na região de molares e de 25% na região de canino. No entanto, não foi observada associação entre o tipo de mordida cruzada posterior e a presença de assimetria nas expansões. As mudanças posturais na mandíbula após a ERMAC não influenciaram as medidas cefalométricas avaliadas, apesar de ter sido observado um movimento predominante no sentido póstero-inferior na região do mento em 70% dos pacientes. A região do gônio apresentou movimentos predominantes no sentido posterior em 60% da amostra, ao passo que os côndilos não apresentaram padrão de deslocamento predominante entre os indivíduos. A análise de correspondência de forma permitiu avaliar as alterações esqueléticas em diferentes regiões da maxila e mandíbula após ERMAC. A expansão maxilar no nível esquelético ocorreu por rotação e inclinação dos segmentos maxilares. Diferentes padrões de expansão foram observados de forma individual, variando desde expansões clinicamente simétricas até expansões assimétricas no qual foi obsrvado expansão em apenas um segmento maxilar. Os deslocamentos mandibulares observados após ERMAC não foram suficientes para promover mudanças significativas no padrão esquelético dos pacientes.
Surgically assisted rapid maxillary expansion (SARME) is a widely accepted technique for treatment of transversal maxillary deficiency in adult patients. This study assessed the three-dimensional (3D) skeletal changes in maxilla and mandible after SARME. A retrospective study was carried out with tomographic records of 20 patients who underwent SARME. 3D cranial base superimposition and shape correspondence analysis were applied to cone-beam computed tomography (CBCT) scans acquired preoperatively (T1) and six months after SARME (T2) in order to evaluate skeletal changes related to SARME, asymmetry during expansion and mandibular changes after SARME. Semitransparent overlays, color and vectors maps were used to perform a visual qualitative analysis of skeletal changes after SARME. Four bilateral regions of interest (ROI) were selected in the maxilla and five ROI were selected in the mandible to quantify the changes from T1 to T2. Non- parametric tests were used for statistical analysis. Statistically significant increases in all maxillary ROI were observed after expansion. Ectocanine and ectomolar regions presented greater displacements than alar and infrazygomatic regions. Asymmetric expansion was found in 40% of the sample in the Ectomolar region, whereas Ectocanine region showed asymmetry in expansion for 25% of subjects. No association were found between the type of posterior cross bite and the presence of asymmetry in expansions. Changes in mandibular positioning had no bearing on the cephalometric measures assessed after SARME; notwithstanding the mandible had showed backward and downward displacements to the Menton region in 70% of the sample. The Gonion regions showed backward displacements in 60% of the sample, whereas the Condyles showed no predominant movements among the individuals of the sample. Shape correspondence analysis allowed to evaluate the skeletal changes in different regions of the maxilla and the mandible after SARME. Maxillary expansion occurred by rotation and tilting of maxillary segments. Different patterns of expansion were found individually, from clinically symmetrical expansion to asymmetric expansion in which only one maxillary segment had moved after SARME. The mandibular displacements observed after SARME were not sufficient to promote significant changes in patients' skeletal pattern.
Surgically assisted rapid maxillary expansion (SARME) is a widely accepted technique for treatment of transversal maxillary deficiency in adult patients. This study assessed the three-dimensional (3D) skeletal changes in maxilla and mandible after SARME. A retrospective study was carried out with tomographic records of 20 patients who underwent SARME. 3D cranial base superimposition and shape correspondence analysis were applied to cone-beam computed tomography (CBCT) scans acquired preoperatively (T1) and six months after SARME (T2) in order to evaluate skeletal changes related to SARME, asymmetry during expansion and mandibular changes after SARME. Semitransparent overlays, color and vectors maps were used to perform a visual qualitative analysis of skeletal changes after SARME. Four bilateral regions of interest (ROI) were selected in the maxilla and five ROI were selected in the mandible to quantify the changes from T1 to T2. Non- parametric tests were used for statistical analysis. Statistically significant increases in all maxillary ROI were observed after expansion. Ectocanine and ectomolar regions presented greater displacements than alar and infrazygomatic regions. Asymmetric expansion was found in 40% of the sample in the Ectomolar region, whereas Ectocanine region showed asymmetry in expansion for 25% of subjects. No association were found between the type of posterior cross bite and the presence of asymmetry in expansions. Changes in mandibular positioning had no bearing on the cephalometric measures assessed after SARME; notwithstanding the mandible had showed backward and downward displacements to the Menton region in 70% of the sample. The Gonion regions showed backward displacements in 60% of the sample, whereas the Condyles showed no predominant movements among the individuals of the sample. Shape correspondence analysis allowed to evaluate the skeletal changes in different regions of the maxilla and the mandible after SARME. Maxillary expansion occurred by rotation and tilting of maxillary segments. Different patterns of expansion were found individually, from clinically symmetrical expansion to asymmetric expansion in which only one maxillary segment had moved after SARME. The mandibular displacements observed after SARME were not sufficient to promote significant changes in patients' skeletal pattern.
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Palavras-chave
Má Oclusão, Técnica de Expansão Palatina, Tomografia Computadorizada de Feixe Cônico, Malocclusion, Palatal Expansion Technique, Cone-Beam Computed Tomography