Evaluation of Stress and Strain on Mandible Caused by Using “All-on-Four” System from PEEK in Hybrid Prosthesis: Finite Element Analysis

Abstract

Background Hybrid prostheses have recently been used to restore the mastication mechanism. These prostheses utilize the “All on four” concept, in which four implants are inserted into the jaw bone and supported by bar. Titanium is usually used in the production of “All on four” parts due to its good mechanical properties, however, it has drawbacks such as aesthetic impairment, casting issues, stress shielding, and incompatibility with imaging techniques. These drawbacks have prompted researchers to find alternative materials (e.g. polymers). Recently, the new polymeric material PEEK, has a major role in dentistry due to its biocompatibility, shock-absorbing ability, and good mechanical and chemical properties. The density of spongy bone is expected to influence the choice of “All on four” material. Objective This work used the finite element method to conduct stress /strain analysis on a mandible rehabilitated with a hybrid prosthesis, by using PEEK in the production of “All on four” parts instead of titanium, using different densities of spongy bone. Methods 3D mandibular model with a hybrid prosthesis was constructed, then “All on four” parts were stimulated with titanium and PEEK materials under different mastication mechanisms. Results PEEK material reduced the stresses and strains on bone tissues and increased the mucosal stress compared to titanium. Consequently, this material was recommended to be used in producing “All on four” parts, especially in the low-density model. Conclusions The density of spongy bone influenced the choice of “All on four” material. Moreover, further researches on PEEK implants and abutments are required in near future.