Finite Element Analysis of Stress Distribution in Different Abutment Designs

Objectives: This in-vitro study used the finite element model (FEM) to investigate 3-dimensional (3-D) stress distribution produced in a 3-unit fiber-reinforced composite inlay fixed partial denture (FRCIFPD) while comparing 3 different preparation designs. Methods: A 3-D FEM of a 3-unit FRCIFPD (227,768 3-D tetrahedral solid elements and 41,617 nodes) was developed. After the validation of the numerical model, three different abutment preparation designs were compared: 1- minimal distal-occlusal and mesial-occlusal preparation; 2- large distal-occlusal and mesial-occlusal preparation; 3- mesial-occlusal-distal preparation of both abutment teeth. Stress distribution generated by a maximum load of 196 N applied vertically to the FRCIFPD centrally, on an area of 4 ± 0.1 mm2, was analyzed. The 3-D FEM allowed to investigate the stress distribution inside the FRCIFPD and in the abutment teeth. Results: The stress distribution was similar for all different preparation designs both in the fixed partial denture and in the abutment teeth. In particular, the peak values of stress were localized in the connector areas on the FRCIFPD and at the cervical margins of the proximal boxes on the abutment teeth. No stress concentration at the occlusal box preparation surface was found for all the preparation designs investigated. Conclusion: Within the limitations of this in-vitro study, the results suggest that the increased extension of the abutment preparations do not result in an improved stress distribution nor in the tooth/restoration complex nor in the abutment teeth.