Sloped marginal configuration design of implants as an alternative innovation to the grafting operations: a three-dimensional finite element analysis

Abstract

Aim: Dental implant operations often require bone grafting due to bone resorption in the buccal area, which make the treatment more complicated, increase the risk of complications, and results in extra costs and prolongation of treatment. This study aimed to evaluate the biomechanical behavior of the implants with a sloped marginal configuration design in the alveolar ridge with a level difference between the buccal and lingual bone levels using three-dimensional finite element analysis (FEA) method. 
 Material and Method: Two implant models with different marginal configuration designs were used in this study. Implants were placed in the posterior edentulous mandible models in which the buccal region had a 2 mm more resorption according to lingual region which were created by imitating natural bone resorption with FEA. Bone grafting was performed on the exposed buccal surface in the conventional flat marginal configuration implant model (Model 1). In contrast, the sloped marginal configuration implants were compatible with the difference in bone level and placed directly without any additional surgical procedures (Model 2). Than three unit fixed partial dentures were designed. The design of cortical and cancellous bones, prosthetic components, implants, abutment screws and abutments covering those in the edentulous mandible models were transferred to digital three-dimensional models that were created to mimicking the real structures. The models were fixed below and behind of the mandible with zero movement. Load transfer characteristics of both models under these essential limitations were evaluated under 200N foodstuff force.
 Results: The highest von Mises stress value was observed as 69.300 MPa in Model 1 and 126.870 MPa in Model 2. The maximum principal stress values were 28.236 N/mm2 and 63.449 N/mm2; the minimum principal stress values were 38.346 N/mm2 and 43.643 N/mm2 in Model 1 and Model 2, respectively. The highest von Mises stress value, maximum principal stress and minimum principal stress values were found higher in Model 2 which was created with sloped marginal configuration design of implants but all values were observed within acceptable physiological limits.
 Conclusion: The sloped marginal configuration design of implants can be a non-invasive and more economical treatment alternative modality compared to conventional flat marginal configuration implants with advanced surgeries during implant placement.