Effect of hyperfunctional occlusal loads on periodontium: A three-dimensional finite element analysis

The periodontal tissue reaction to variations in occlusal forces has been described in the literature wherein clinical and histologic changes are discussed that produced due to stresses in the periodontal structures. Unfortunately, these stresses are not quantified.

The aim of this study is to determine the stress produced on various periodontal tissues at different occlusal loads using finite element model (FEM) study.

Four FEMs of maxillary incisor were designed consisting of the tooth, pulp, periodontal ligament (PDL), and alveolar bone at the various level of bone height (25%, 50%, and 75%). Different occlusal load (15 and 29 kg) at an angle of 50° to the long axis of the tooth was applied on the palatal surface at the level of 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 processor computer using the ANSYS software.

At normofunction load, the stresses were maximum on the mesial side near the cervical region at point D for tooth (-10.93 Mpa) for PDL (-4.06 Mpa) for bone (-4.3 Mpa) with normal bone levels as the bone levels decreased the stresses increased and the stresses tend to concentrate at the apical region. At any given point, the stresses were increased by 90% at hyperfunctional load.

Based on the findings of the present study, there is reasonably good attempt to express numerical data of stress to be given normal occlusal and hyperfunctional loads to simulate clinical occlusal situations which are known to be responsible for healthy and diseased periodontium.