Evaluating Stress Distribution in Bone Adjacent to Implant in Various Abutment-Implant Connection Designs

Abstract

BACKGROUND
The biomechanical integrity of dental implants is significantly influenced by the design of the abutment-implant connection. Different connection geometries can alter stress transfer to the surrounding bone, which may impact implant longevity and osseointegration. This study aims to assess and compare the stress distribution in peri-implant bone associated with three commonly used abutment-implant connection designs: external hex, internal hex, and conical connection.

MATERIALS AND METHODS
A three-dimensional finite element analysis (FEA) was performed using computer-aided design (CAD) models of mandibular bone with a single implant in the posterior region. Implants with external hex, internal hex, and conical abutment connections were analyzed. A vertical load of 150 N and oblique load of 100 N at 30° were applied to simulate masticatory forces. Stress distribution in cortical and cancellous bone was evaluated using von Mises criteria.

RESULTS
Under vertical loading, the maximum stress observed in cortical bone was 55.2 MPa for the external hex, 48.6 MPa for the internal hex, and 36.9 MPa for the conical connection. Oblique loading yielded higher stress values: 78.4 MPa for the external hex, 66.7 MPa for the internal hex, and 52.3 MPa for the conical connection. Cancellous bone exhibited lower overall stress values in all models. The conical connection demonstrated the most favorable stress distribution, with reduced stress concentration at the crestal bone.

CONCLUSION
The type of abutment-implant connection significantly influences stress distribution in adjacent bone. Conical connections exhibit superior biomechanical performance by minimizing stress concentration, suggesting their potential benefit in enhancing long-term implant stability.