Evaluation of stress and strain on mandible caused by changing the bar material in hybrid prosthesis utilizing “All-on-Four” technique

[Display omitted] •The appropriate treatment for edentulous patients is performed by the use of “complete denture”, “implant retained denture” and “implant supported fixed denture” to restore the quality of life.•The hybrid prosthesis consists of a bar which attached to the copings over the abutments and implants.•Protocol bars are usually made of metallic materials. The limitations of metal lead the researchers to search for alternatives materials such as ceramics, polymers and composites.•The distribution of tensile and compressive stresses/strains in any object can be visualized by the extraction of max and min principal stresses/strains. Full edentulism is the complete loss of teeth which affects mastication. The treatment is performed by using the hybrid prostheses to restore the mastication mechanism. The materials of choice for the bar in the hybrid prostheses are titanium and gold. The limitations of metals encourage the researchers to find alternatives materials. This research investigated the possibility of using ceramics, polymers and composites as a bar material instead of titanium. 3D model of mandible with hybrid prosthesis was stimulated with different bar materials. The von Mises stress of each part was extracted, besides the max& min principal stresses /strains were computed for the bone parts. By using PEEK bar, the von Mises stresses on cortical and cancellous bones reduced by (3.4&3.02 %) and (10.4 &3.36 %) under unilateral and bilateral forces, besides the mucosa stress increased to 0.121 and 0.135 MPa respectively. For all used materials, the stresses and strains of bone parts did not exceed the critical limits, besides the mucosa stress was lower than the pain threshold value. As a consequence, it was concluded that all materials included in this study could be used as an alternative to titanium as a bar material.