Evaluation of stress distribution in maxillary anterior bone from three different tapered implant thread designs with two angulated abutments: A 3-dimensional finite element analysis study

Background: Tapered implants imitate the natural form of the root. They are known to enhance primary stability by providing pressure on the cortical bone of regions with poor bone qualities and also has a good survival rate as it directs stresses away from the crestal cortical bone while transferring it to the cancellous bone. Purpose: Maxillary anatomic constraints sometimes make it necessary to surgically position implants at angles that are not optimal for prosthetic restorations or by positioning the implant in the area with the greatest available bone, with the intention of correcting the implant alignment at the time of prosthetic restoration. This is made possible, in carefully planned cases with the use of angulated abutments. Materials and Methods: Three tapered implants with triangular, square, and buttress thread designs having a 15° and 25° angulated abutment were created. The implant models were positioned in anterior maxillary bone D2 and D3 and clinical loading conditions simulated. The maximum equivalent von Mises stress values were recorded and analyzed using ANSYS software. Results: The finite element analysis carried out showed less stresses from tapered implant square thread design in D2 and D3 bone with 15° angulated abutment, while buttress thread design performed better in D2 and D3 bone with 25° abutment angulation on axial and nonaxial loading. Conclusion: Bone type is an important factor that affects stress distribution. More stress occurred in D3 bone compared to D2 bone type. Thus, bone type should be carefully considered when choosing the most appropriate implant design.