Influence of alveolar bone loss, post type, and ferrule presence on the biomechanical behavior of endodontically treated maxillary canines: strain measurement and stress distribution.

STATEMENT OF PROBLEM: Teeth restored with posts are more frequently associated with bone loss, but there is no evidence to suggest that the post type and the presence of bone loss influence biomechanical behavior. PURPOSE: The purpose of this study was to evaluate the effect of alveolar bone loss, post type, and ferrule presence on the biomechanical behavior of endodontically treated maxillary canines. MATERIAL AND METHODS: For the experimental analysis, 40 human canine teeth were selected and divided into 8 experimental groups (n=5) according to 3 treatment variations: with or without 5.0 mm of bone loss (bl), with or without a ferrule, and restored with cast post and cores or glass fiber post. The restored canines were loaded at 15 degrees, and deformation was measured with strain gauges placed on the buccal and proximal root surfaces. Strain results were analyzed by 3-way analysis of variance (ANOVA) and the Tukey HSD tests (alpha=.05). For the finite element analysis, eight 3D models were created by following the same variations of the experimental analysis. The models were analyzed by using the maximum principal stress criteria for stress distribution analysis. RESULTS: The absence of a ferrule significantly increased the buccal and proximal strain values. The post type influenced the stress distribution, mainly at the interface of post and dentin. The bone loss significantly increased the stress concentration and strain values, mainly on root dentin and surrounding cortical bone. CONCLUSIONS: The presence of a ferrule improved the mechanical behavior. The 5.0 mm of bone loss significantly increased the stress concentration and the strain on the root dentin.