The Effect of V-Thread and Square Thread Dental Implants on Bone

The relationship between implant thread design and dental bone arguably has an influence on the distribution of bone stresses. However, the existing data on the influence of thread profiles on bone stresses is considerably conflicting. For example, some studies concluded that thread shape has a substantial effect on the intensity of bone stresses, while others revealed that thread shape has no effect on the intensity of bone stresses. Accordingly, this study aims to computationally investigate and compare the effect of dental implant thread design on bone stresses under axial loading using a finite element analysis (FEA) approach. A geometrical model of V-thread and square thread implants with a fixed thread pitch of 0.8 mm and a depth of 42 mm and the surrounding bone were developed to assess the stresses generated within the implant components and bone structure under a 114 N axial load. The simulation is primarily concerned with the von Mises stresses within the implant components and the surrounding bone. The results demonstrate that the V-thread implant causes extremely high stress on the cortical and cancellous bones compared to the square thread implant. For example, the maximum stresses induced in the cortical bone are 195.3 MPa and 68.8 MPa, while the maximum stresses created in the cancellous bone are 19.7 MPa and 2.2 MPa in both designs, respectively. In addition, the cortical bone stresses substantially exceed the implant body stresses in both designs, with maximum stresses of 93.18 MPa and 41 MPa for V-thread and square-thread implants, respectively. However, the implant thread shape does not affect the stress distribution in the abutment and screw. In general, the results show that implant thread design can result in featured mechanical stresses in the implant body and bone structure.