Three-dimensional finite element analysis of stress in the apical cementum of the maxillary central incisor with simulated orthodontic tooth movement.
This study was conducted to determine the different apex cementum thickness that causes high stress at the root apex. A 3-dimensional finite element model of a maxillary central incisor and its enamel, dentine, pulp, cementum, alveolar bone and periodontal ligament was constructed on the basis of average anatomic morphology. The tooth model created in this study is a significant enhancement from previous finite element studies both in the number of elements and morphology. The maxillary central incisor was chosen for study because it is the tooth at greatest risk for apical root resorption. The 5 different apical cementum levels (200mum, 400mum, 600mum, 800mum and 1000mum) with intrusive force were tested. The finite element analysis showed that stresses around the root apical are increased proportionally to the increase of apex cementum thickness, and a sharp increase in the stress value was observed between 800mum to 1000mum of apex cementum.