Evaluation of induced stress in PDL of anterior maxillary teeth by applying intrusive forces distal to the maxillary canine

Abstract Background: One of the precise methods for evaluating periodontal responses to orthodontic forces is finite element method. Objective: The aim of this study was to evaluate induced stresses in PDL of anterior teeth by application of intrusive forces distal to the canine. Methods: Solid works software was used to translate bidimentional images of the maxillary teeth (central, lateral, canine) into tridimentional images. PDL and alveolar bone around teeth were simulated and anterior teeth were positioned in an ideal arch with appropriate tip and torque, and rectangular wire was stabilished rigidly on labial surfaces of the teeth. Models were modified to “Finite element model” by means of MSC-NASTRAN. Intrusive forces (35gr) were applied on anterior wire distal to the canine and induced stresses were analyzed by means of MSC-PATRAN. Findings: By delivery of intrusive forces between the lateral and canine teeth, the maximum stress was concentrated in PDL of canine (8.38×10-3 N/mm2) and the minimum stress was in PDL of central (7.6×10-6 N/mm2). Conclusion: Application of intrusive forces on the distal of canine teeth lead to un hemogenous stress distribution in anterior area due to intrusive and unitended labiodistal movement. Therfore distal of canine is not an appropriate point for intrusive forces application.