Evaluation of Stress Patterns in Bone Around Implants for Different Abutment Angulations Under Axial and Oblique Loading in Anterior Maxillary Region—A Finite Element Analysis

Abstract

Introduction Replacing missing anterior teeth with a prosthesis that resembles natural form and function has always been challenging for a prosthodontist. Removable and fixed options both have been extensively studied and researched upon. In modern dentistry, implants have proved to be a more logical option for the same. The morphology of bone present in the premaxilla serves as guide to plan implant angulation during osteotomy. Factors such as age-related bone resorption, trauma or pathologic bone resorption due to periodontitis, etc. causes implants to be placed at angles that are difficult to restore with conventional straight abutments. Angled abutments can help build up favorable functional prosthesis in such cases, but they experience the drawback of transferring unfavorable forces to the implant or bone, thereby compromising the prognosis of the treatment. Clinically, the effect of these forces is difficult to evaluate, so a finite element analysis was done to estimate stress distribution at the bone implant interface. Materials and Methods In this study, premaxilla was modeled with 15 mm in bone height, 7 mm in bone length, and 12 mm in bone width with 1.5 mm thick cortical bone surrounded by a core of cancellous bone. The implant was modeled as a cylindrical, round-ended device with dimensions, 4.3 mm × 11.5 mm. Abutments with angulations 0°, 10°, 15° and 25° were used. To simulate clinical conditions, a 100 N load axially and 30 N load obliquely was applied. Result It was seen that, as the abutment angulation changes from 0° to 25°, both the compressive as well as tensile stresses increased; however, they were within the tolerance limit of the bone. Conclusion The study suggests angled abutments can be used with reasonable success, keeping in mind the basics of implant prosthodontics intact.

Evaluating Angled Abutments: Three-Dimensional Finite Element Stress Analysis of Anterior Maxillary Implants

“…In the studies conducted by Clelland et al [33] and Papavasiliou et al [34], the simulation results demonstrated that stresses were concentrated in the cortical bone, and the magnitude of these stresses increased with increases in the abutment angulation. Interestingly, our research yielded similar results, with observed increases in stress values associated with higher abutment angulations [35][36][37][38]. Baggi et al [19] showed that the implant neck bears the maximum load due to contact stress.…”