Effect of the post geometry and material on the stress distribution of restored upper central incisors using 3D finite element models. Stress distribution on incisors with posts

This study evaluated the effect of geometry and material of posts on the stress distribution in maxillary central incisors, using the finite element method. Four 3D models were developed: (i) healthy tooth and restored teeth using (ii) tapered, (iii) cylindrical and (iv) two-stage cylindrical posts. Materials used were stainless steel, titanium, zirconium dioxide, carbon and glass fibers on Bis-GMA matrix. Two stress concentration regions were verified: (i) adjacent to the alveolar bone crest and (ii) dentin-post boundary. Tensile and compressive stresses were concentrated on the palatal and facial surface, respectively, for all the analyzed models. In the dentin portion close to the alveolar bone crest, different anatomical form and material posts presented similar patterns of stress distribution. However, in the dentin-post boundary, more favorable results were presented by glass fibers and carbon fibers posts, followed by titanium, being the worst results associated to the use of stainless-steel or zirconium dioxide posts. Still in the dentin-post boundary, tapered posts presented more favorable results than cylindrical posts, followed by two-stage cylindrical posts, which presented the highest levels of stress concentrations. It was concluded that the insertion of post alters the pattern of stress distribution when compared with the healthy tooth and that smaller stress concentrations are associated to the use of glass fiber or carbon fiber tapered posts.