Fracture Toughness of Different Adhesive/Dentin Interfaces by Laboratory Testing Versus Finite Element Models: An In Vitro Study

Abstract

Our study aimed to measure and compares the fracture toughness value of different adhesives-dentin interfaces by laboratory testing and by finite element analysis before and after 6 months of storage in distilled water. In this study the fracture toughness of adhesive-dentin interfaces was determined using a chevron-notched beam (CNB) test. The prepared chevron notch caused the fracture to propagate along the adhesive interface when subjected to 4-point bending test setup using a universal testing machine after 24 hours. Specimen storage for 6 months in distilled water was done to test the durability and predict the longevity of resin dentin bond. Finite element analysis has been used to measure the fracture toughness value by analyzed the von Mises and maximum principal stresses of the adhesive layer at the adhesive-dentin interface induced by the fracture loads obtained from the experimental work and to compare the fracture toughness results with the finite element analysis results. The results of the fracture toughness value test different adhesive systems showed that the multi-step adhesives bonded more effectively than simplified one-step adhesives, Self-adhesive resin cement showed the lowest fracture toughness values after 24 hours and 6 month due to the relative shallow interaction with the underlying dentin.