Evaluation of Shear Bond Strength of Resin Reinforced Glass Ionomer Cement Modified by Nano-hydroxyapatite on Ceramic Bracket Debonding Using Full-dimension Wire

Abstract

Aim: Using fluoride releasing materials such as Glass Ionomer Cement (GIC), can control the demineralization around brackets. In this study, the shear bond strength of resin reinforced GIC modified by Nano-hydroxyapatite (NHA) on ceramic bracket debonding is evaluated. In addition, using full-dimension wire for safe debonding is also examined. Study Design: Original article. Place and Duration of Study: Department of Dentistry, Shahed University, Tehran, IRAN, June 2013. Methods and Material: 80 extracted human premolars received from a clinic were partitioned into 4 groups. Bonding materials used in each group was as follows: Group 1: Transbond XT as a control group, Group 2: Resin Modified GIC (RMGIC), Group 3: RMGIC added 5% NHA and Group 4: RMGIC added 10% NHA. In all groups the enamel was etched with 37% phosphoric acid and ceramic brackets were used. Each group halved into 2 subgroups which just in one of them full dimension wire was employed at the time of debonding. The shear bond strength, Adhesive Remnant Index (ARI) and bracket failure figures were collected for each group. The data was latter analyzed using one-way Analysis Of Variance (ANOVA), Tukey’s HSD (Honestly Significant Difference) Post-hoc and Kruskal Wallis Test methods. Results: According to ANOVA, RMGIC added 5% NHA has no negative effect while adding 10% NHA lowered the shear bond strength significantly. No bracket failure occurred at debonding, either using or not using full dimension wire. ARI for RMGIC groups were more cohesive than the control group. Conclusion: RMGIC containing 5% NHA contributes bond strength similar to composite resins, in bonding ceramic brackets, while its known demineralization resistance is a favor.