An investigation on stress distribution of the anterior maxillary teeth PDL during the application of intrusive forces in midline

Finite element method is one of the highly precise methods to evaluate periodontal responses to orthodontic forces. The goal of the present study was to investigate the PDL response of anterior maxillary teeth (central, lateral, canine) during the application of intrusive forces using FEM. Solid works software was used to translate bidimensional images of the mentioned maxillary teeth into tridimensional ones. Then, PDL and alveolar bone were simulated around teeth and anterior teeth were positioned in an ideal arch with appropriate tip and torque and rectangular wire was placed rigidly on labial surfaces of teeth. These models were then modified to "Finite element model" by MSC-NASTRAN software. Intrusive forces were applied mesially on the anterior wire and induced stresses were analyzed by MSC-PATRAN. The maximum stress was observed in the PDL of lateral incisors (2.5310-3 N/mm2) and the minimum stress was in the PDL of canines (9.0710 -3 N/mm2). Applying the intrusive forces in midline maximum stresses were focused on the apical part of lateral incisor and the minimum stersses were in the apically third of canine.