Shear Bond Strength of Resin-Modified Glass Ionomer Cement as a Result of Enamel Surface Modifications

Abstract

Objectives: To determine the mean shear bond strength (SBS) of metallic brackets bonded with Resin Modified Glass Ionomer Cement (RMGIC) after deproteinization by using sodium hypochlorite, 5.25% (NaOCl) prior to acid etching.

Methods: The Department of Orthodontics, Lahore Medical & Dental College conducted an in vitro experimental study over a period of 2 months. Eighty healthy and fully developed human premolars were randomly allocated into group A and B. In Group A, the teeth were treated with sodium hypochlorite, 5.25% for 1 minute before phosphoric acid, H₃PO₄ (37%) etching and moistened with water, then brackets were bonded using RMGIC as an adhesive material. In Group B, the teeth were treated with H₃PO₄ (37%) only and the brackets bonded directly with RMGIC. The SBS was evaluated in both groups.

Results: There was a significant difference between the mean shear bond strength (SBS) between the two groups. After deproteinization, it was higher (significant) in group A (11.33) than in group B (6.53) [Mean difference =4.80±0.95; p=0.0005]. 

Conclusion: Deproteinization with NaOCl (5.25%) for 1min before Phosphoric acid (37%) etching results in significantly higher shear bond strength with RMGIC. Therefore, deproteinization can save chairside time that might get wasted due to frequent debonding of brackets.