Evaluation of Fracture Resistance of Long Span Implant Supported Fixed Dental Prostheses Fabricated from Different CAD/CAM Materials.

Abstract

Objective: Implant prosthetic materials capable of reducing mechanical stresses on the implants and supporting structures in case of long span implant supported FDPs are highly required. The purpose of this study was to evaluate the fracture resistance of CAD/CAM long span implant supported fixed dental prostheses fabricated from PEKK compared to PEEK and zirconia. Material and methods: Two implants with straight abutments were inserted in a metal model representing lower first premolar and second molar. Twenty-one frameworks of four-unit FDPs were fabricated on the master model from three materials; Polyetheretherketone (PEEK), Polyetherketoneketone (PEKK) and Zirconia, and divided according to type of material into three groups (n = 7). The cemented frameworks were loaded until fracture by using computer controlled universal testing machine (Modcl 3345; Instron, USA) with a 5 KN load cell. The load at failure manifested by an audible crack and confirmed by a sharp drop at load-deflection curve recorded using computer software (Instron Blue hill Lite Software) and this value was recorded in Newton. Results: The mean fracture resistance values were [612.31±27.41N], [334.44±20.54N] and [1334.20±176.71N] for the PEEK, PEKK and Zirconia groups respectively. There were statistically significant differences between the three material groups. Conclusion: The fracture resistance values of the long span implant supported FDPs were affected with the material type. All the values obtained in this study fall above the mean masticatory force value in the posterior region with caution in PEKK design.