Three-dimensional finite element analysis of stress in the periodontium

The aim of this study is to calculate the stress produced in the periodontium at different bone levels under occlusal load. Four finite element models of maxillary incisors were designed consisting of the tooth, pulp, periodontal ligament and alveolar bone at various levels of bone height (25%, 50% and 75%). An occlusal load of 24 kg at an angle of 50 degrees to the long axis of the tooth was applied on the palatal surface, at the level of the middle third of the crown. All the models were assumed to be isotropic, linear and elastic and the analysis was performed on a Pentium IV computer using the NISA II Display III software. The results showed that maximum stress in the tooth was seen at the cervical region and to a greater extent at the apex for all the models. In periodontal ligament, maximum stress was seen at the alveolar crest in models with normal alveolar bone height and with reducing alveolar bone height maximum stress was at the apex. There was no significant stress distribution in alveolar bone, while no stress was seen on the pulp. The results of the study demonstrated a significant increase in stress concentration at the apex with loss of alveolar bone height.