Evaluation of post-surface conditioning to improve interfacial adhesion in post-core restorations

AIM: To examine the influence of different post-surface treatments on the interfacial strength between epoxy resin-based fiber posts and methacrylate-based resin composites that are employed as core build-up materials. MATERIALS AND METHODS: Forty clear posts were divided into four groups of 10 each. The different surface treatments used were etching with alkaline potassium permanganate, 10% hydrogen peroxide, 37% phosphoric acid, and silanization alone. After etching and thorough rinsing, a single layer of silane was applied to the post surface. Then the post was placed in a rectangular plastic matrix and core bulid-up was done using Multi Core, a dual cured composite resin. A slab of uniform thickness, with the post in the center and the core build-up composite on either side was created. The specimens were cut so as to obtain microtensile sticks that were loaded in tension at a cross-head speed of 1 mm/min until failure. The statistical analysis was performed using two-way ANOVA and the paired T test for post-hoc comparisons. RESULTS: The results achieved with potassium permanganate had a significant influence on microtensile interfacial bond strength values with the tested material. CONCLUSION: Surface chemical treatments of the resin phase of fiber posts enhance the silanization efficiency of the quartz fiber phase, so that the adhesion in the post/core unit may be considered as a net sum of chemical and micromechanical retention.