Mandibular symphysis morphology and dimensions in different anteroposterior jaw relationships

Abstract

Objective: To assess the morphology and dimensions of mandibular symphysis (MS) in different anteroposterior jaw relationships and to investigate whether craniofacial parameters have any correlation with its shape and/or dimensions. Materials and Methods: Lateral cephalograms of subjects with Class I, Class II, and Class III skeletal relationships were traced. Several craniofacial and MS parameters were measured. MS parameters were compared between the three groups using analysis of variance and were correlated with the craniofacial parameters using the Pearson correlation coefficient. Results: Larger angle of concavity of the chin, more inclination of the alveolar bone toward the mandibular plane, and larger MS dimensions and area (P , .001) were found with a Class III skeletal relationship compared to Class I and Class II relationships. The Pearson correlation coefficient between Id-Me and AFH was r 5 0.83 and between Id-Me and LAFH it was r 5 0.81. Conclusions: The dimensions and configuration of MS in the Class III relationship were different than those in Class I and Class II relationships; the alveolar part of MS compensated for the skeletal relationship in the Class III pattern. MS dimensions were strongly correlated to anterior facial dimensions. (Angle Orthod. 2014;84:304-309.)

Study of the effect of the shape of the miniplate on the stability of mandibular symphyseal fracture using finite element analysis

“…[10] Multiple researches have studied the biomechanical behavior of the mandible that is fractured at the angle and condylar process after reduction and fixation with miniplate using finite element analysis however the symphyseal fracture has not explored sufficiently. [11,12] Through this study, the fractured segment of the mandible was represented with two separated blocks having the same dimensions of the mandibular symphysis as regards the height, the width and thickness according to the study of Alkhateeb et al [6] .…”

“…The region of symphyseal fracture was simulated simply by sketching the fracture through an acrylic block which is 15 thickness and 40 in height as the same dimensions of the symphysis according to the study of Alkhateeb et al [6] .…”

A CBCT Analysis of Optimal Maxillary and Mandibular Incisor Inclination

“…Another factor that must be considered when trying to define tooth position in the alveolus is the different types of skeletal and dental malocclusions. [35]. Inclination of incisors also varies based on the skeletal and dental relationship of Class I, II, and III patients.…”

Avaliação tridimensional da descompensação dentária e remodelação óssea pré-cirúrgica nas más oclusões de classe III

“…Quando, os ossos basais, como a maxila ou mandíbula, se desviam do padrão de crescimento esperado, as estruturas craniofaciais remanescentes reagem como uma tentativa de mascarar a discrepância. Desta forma, durante o crescimento, os dentes podem sofrer alterações nas suas posições axiais e verticais, em resposta a este crescimento esquelético desarmonioso, que são as chamadas compensações dentárias (Solow, 1980;Jacobs, 1991;Molina-Berlanga et al, 2013)., Al-Khateeb et al, 2014 concluíram que indivíduos classe III apresentam menor concavidade anterior da sínfise mandibular e uma maior inclinação da parte alveolar da sínfise em relação ao plano mandibular. Isto porque a retroinclinação dos incisivos inferiores poderia levar a uma remodelação da superfície externa da parte dentoalveolar da sínfise (Mulie e Ten Hoeve, 1976 Outros estudos como os de (Ellis;Mcnamara, 1984;Yamada et al, 2007) inferiores, visto que a medida que a raiz dentária se move em direção posterior, o ponto B também se movimenta na mesma direção.…”

“…Indivíduos com más-oclusões de Classe III e predomínio do vetor vertical de crescimento apresentam a sínfise mandibular predominantemente estreita, com pouco osso alveolar por vestibular e por lingual às raízes dos incisivos inferiores (Handelman, 1996). A inclinação dos incisivos inferiores pode afetar a morfologia da sínfise mandibular durante o crescimento ou compensação dentoalveolar (Al-Khateeb et al, 2014). O entendimento da morfologia da sínfise é importante porque serve como referência primária para a estética do perfil facial e é determinante no planejamento da posição do incisivo inferior durante a ortodontia e cirurgia ortognática.…”