Finite Element Analysis of the Stresses Induced by One- Piece and Two-Piece Dental Implants Supporting All-on-4 Implant-Supported Prostheses

Purpose: To find out the difference in the stresses induced by one-piece monophasic and two-piece dental implants supporting All-on-4 implant-supported prostheses using finite element analysis. Materials and Methods: Two finite element maxillary models were designed: In the two-piece model, two-piece dental implants were used, and in the onepiece model, one-piece dental implants were used. The dental implants were placed according to the All-on-4 treatment concept. The anterior implants were axially placed; however, the posterior implants were placed with a distal inclination of 15 degrees. In each model, the prosthetic superstructure was designed to be a titanium implant prosthesis with zirconia crowns. Three loading scenarios were applied in this study. The first scenario simulated biting function with a total load of 250 N. The second scenario simulated incision function in which 90-N horizontal static load was applied to the palatal surface of central incisors. The third scenario simulated biting in the presence of a cantilever. Results: In the three loading scenarios, the stresses were higher in the two-piece model. Higher stress values were recorded posteriorly rather than anteriorly in both models. Conclusion: One-piece dental implants induce lower stress values compared with two-piece dental implants when used in All-on-4 implant-supported prostheses.