Influence of food-simulating liquids on bond strength of brackets bonded with a HEMA-free and HEMA-containing self-etching primer

Abstract

Objective: To evaluate the effect of food-simulating liquids on bond strengths of brackets bonded with a HEMA-free and a HEMA-containing self-etching primer. Materials and Methods: Brackets were bonded to 280 bovine incisors that were divided into two groups: (1) Adper Prompt-L-Pop (Adper PLP)/Transbond-XT and (2) Transbond Plus self-etching primer (TSEP, HEMA-free)/Transbond-XT. Each group was evaluated under different storage conditions: 24 hours in water, thermocycling (T), T/12 weeks in water, T/12 weeks in 10% ethanol, T/12 weeks in 50% ethanol, T/12 weeks in 3% acetic acid, and T/12 weeks in olive oil. Shear bond strength was measured with a universal test machine. Results: TSEP and Adper PLP showed a significantly higher bond strength at 24 hours than at T/12 weeks in 50% ethanol (P = .000). For Adper PLP, the bond strength at 24 hours was significantly higher than T/12 weeks in water (P = .000). Significant differences were not detected between the two bonding procedures for the different storage conditions (P > .05). Conclusion: Owing to its hydrophilic nature, the bond strength produced by Adper PLP (a HEMA-containing self-etching primer) decreased significantly after T/12 weeks in water. Brackets bonded with both TSEP and Adper PLP showed significantly higher bond strengths at 24 hours than at T/12 weeks in 50% ethanol, probably due to the effect of ethanol at 50% on Transbond-XT.