Abstract
Purpose: To compare the effect of different surface treatments (pre-treatments and bonding agents) on the bond strength between glass-fiber post and composite resin, and the topographic alterations of the treated post surface.
Methods: Thirty-six glass-fiber blocks (12 mm × 10 mm × 8 mm) were specifically manufactured for this study and randomly assigned into 12 groups considering two factors: 'pre-treatments' (-cleaning with 70% alcohol; air-abrasion with silica-coated aluminum oxide particles; 35% hydrogen peroxide) and type of 'bonding agent' (no bonding agent; application of Monobond Plus; RelyX Ceramic Primer; Single Bond Universal). After that, 6 cylindrical templates ( 1mm high × 1 mm Ø) were fixed on each block, filled with composite resin (n = 18) and light-cured. Specimens were stored under 37 °C for 24 h and microshear tests (wire loop Ø = 0.2 mm) were performed. Topographic, roughness and failure analyses were also performed.
Results: Different surface pre-treatments led to different topographic and roughness alterations; a higher surface alteration was noted after silica particles air-abrasion, while a slight surface alteration in the hydrogen peroxide group and a smooth pattern were observed in the cleaning group. The factors 'pre-treatments' (p < 0.05), 'bonding agent' (p < 0.05) and their interaction (p < 0.05) influenced the bond strength. Silica coating, apart from bonding agent application, or Single Bond Universal application without pre-treatment promoted the highest bond values. The main failure type was adhesive at the resin-post interface.
Conclusions: In terms of pre-treatments, silica coating promotes the best bonding performance, but pre-treatments can be dispensable when applying Single Bond Universal.
