Effect of Sterilization on Bond Strength and Mechanical Properties of Fiber Posts.

PURPOSE: To determine the effects of two different sterilization methods on the pull-out bond strength, flexural strength, and elastic modulus of glass-fiber posts. MATERIALS AND METHODS: A total of 69 glass-fiber posts were used. The posts were divided into three groups according to applied sterilization method: 1) control, 2) ethylene oxide gas (EOG), and 3) autoclave. The microstructure of three posts from each group was evaluated by SEM and energy-dispersive X-ray spectroscopy (EDS). Thirty glass-fiber posts were used to evaluate pull-out bond strength. The three-point bending test was performed to analyze the flexural strength on another 30 glass-fiber posts. Failure modes were categorized microscopically after the pull-out test. After the three-point bending test, micromorphology at the bending area was examined using SEM. RESULTS: One-way ANOVA indicated no statistically significant differences among the group means in terms of bond strength (p > 0.05), flexural strength (p > 0.05), or elastic modulus (p > 0.05). EDS revealed that the weight percentage of surface oxygen atoms in the EOG- and autoclave-sterilization groups were significantly higher. SEM images were similar. CONCLUSION: The results of this study show that glass-fiber posts can be sterilized either by autoclave or EOG when necessary, without any negative effect on bond strength, flexural strength, or elastic modulus.