Fracture analysis of post material and bonding condition on a cylindrical Glass-Resin Bilayer structure

Abstract

© 2019, Journal of International Dental and Medical Research. The study aimed to develop a biomechanics model to identify the effects of post material and bonding condition on the vertical cracking of a glass-resin bilayer structure under applied axial load. The specimens consisted of cylindrical glass tubes, in which metal or fiber posts were centered and which were filled with a resin core material. Fifty specimens were divided into five groups, a control group without posts, and four experimental groups, depending on the type of post and whether bonding was used. A static load was applied using a universal testing machine and continued at 0.01 mm/min until fracture. The failure load was compared using statistical analysis (p < .05). Failure rate, fracture patterns, and failure probability were analyzed. The control group had the highest failure rate compared to groups in which posts were used. Bonded posts had no significant difference in failure rates, whereas unbonded metal posts had a higher failure rate than unbonded fiber posts. Unbonded metal posts had a significantly higher failure rate than bonded metal posts, whereas both unbonded and bonded fiber posts had no significant difference in failure rates. Post material and bonding condition affect the fracture resistance of the model. Metal and fiber posts may have similar fracture rates in cases with good bonding condition; however, fiber posts present a lower fracture rate than metal posts in cases with no bonding. Bonding condition can change peak stress concentration from the cervical area to the middle third of the glass tube.