Mechanical behavior of endodontically restored canine teeth: Effects of ferrule, post material and shape

To assess the effect of a ferrule design with specific post material-shape combinations on the mechanical behavior of post-restored canine teeth. Micro-CT scan images of an intact canine were used to create a 3-D tessellated CAD model, from which the shapes of dentin, pulp and enamel were obtained and geometric models of post-endodontically restored teeth were created. Two types of 15 mm post were evaluated: a quartz fiber post with conical–tapered shape, and a carbon (C) fiber post with conical–cylindrical shape. Four models were analysed by Finite Element (FE) Analysis: with/without a ferrule for both types of post material and shape. In all models, the highest stresses were in the palatal wall of the root. Models with the C-fiber post had higher stress than models with the quartz fiber posts. The most uniform stress distribution was with the combination of ferrule and quartz fiber post. The FE analysis confirmed a beneficial ferrule effect with the combination of ferrule and quartz fiber post, with tapered shape, affording no critical stress concentrations within the restored system.