A Three-dimensional Finite Element Analysis of Stress Distribution in the Cortical Bone in Single Tooth Implant and Post Core-treated Tooth subjected to variable Loads

Abstract

Purpose: In spite of many advances in the field of prosthetic dentistry, the choice of whether to treat and retain a grossly compromised tooth or to extract and replace with an implant is debatable. Alveolar bone preservation is one of the main criteria to select the treatment option. This is directly affected by the stress generated in the cortical bone under variable loads and is therefore, relevant. Materials and methods:Two three-dimensional finite element models were generated in relation to maxillary second premolar using ANSYS software. Model-I was parallel-tapered titanium implant with screw-retained titanium abutment and porcelain fused to metal (PFM) crown. Model-P was fiber post and composite resin core with PFM crown. Luting cement was resin cement. Both the models were surrounded by homogeneous and isotropic cortical and cancellous bone, and were subjected to variable loads of 300, 400, and 500 N in axial (0°) and nonaxial (15°, 45°) directions. Results: Stress in the cortical bone in megapascal (MPa) inModel-I/Model-P when subjected to variable loads in newtons (N) in axial direction was 300 N -37.6 MPa/47.3 MPa; 400 N -50.2 MPa/63.0 MPa; 500 N -62.7 MPa/63.0 MPa. 15°-300 N -68.5 MPa/65.9 MPa; 400 N -91.3 MPa/87.9 MPa; 500 N -114.2 MPa/87.9 MPa. 45° -300 N -136.3 MPa/88.9 MPa; 400 N -181.8 MPa/118.5 MPa; 500 N -227.2 MPa/118.5 MPa. Conclusion:Within the limitation of this study, it was concluded that on axial loading, both the treatment modalities showed no significant difference, but on nonaxial loading, the cortical bone in the implant model showed to have considerably higher stress than post core-treated tooth model. Hence, given a choice, this study favors retaining and restoring a compromised tooth with post core and crown rather than extracting and replacing with an implant.