Distribution of Micromotion in Implants and Alveolar Bone with Different Thread Profiles in Immediate Loading: A Finite Element Study

Purpose: To detect the differences in the distribution of micromotion within implants and alveolar bone with different implant thread designs during immediate loading. Materials and Methods: A three-dimensional finite element model with contact elements was used to simulate the contact behavior between the implant and alveolar bone. Implants with four different thread designs were created: Acme (trapezoidal) thread (AT), buttress thread (BT), square thread (ST), and a standard V-thread (VT). To simulate immediate loading, the model was designed without osseointegration between the implant and alveolar bone. A load of 300 N was applied axially to the model, and the micromovements were measured. Results: The maximum micromotion values of the ST, AT, VT, and BT models were 8.53, 9.57, 11.00, and 15.00 µm, respectively. All micromotion was located near the interface of cortical and cancellous bone. Different thread designs showed different distribution of micromotion during loading. This indicates that initial stability in immediate loading may be affected by thread design. Conclusion: The ST profile showed the most favorable result in the study. An implant with an ST profile might provide the best primary stability in an immediate loading situation.