Effect of two bleaching regimens on enamel bonding performance

Abstract

This study evaluated the post-bleaching bonding performance of a one-step and two-step self-etch adhesive (SEA) to bleached enamel using in-office or at-home bleaching. Bovine enamel surfaces were treated with an in-office or at-home bleaching agent and divided into four post-bleach time periods: immediate, one day (1d), one week (1w) and one month (1m) before application of SEA systems. Enamel was bonded using the following procedures: Group 1: one-step SEA application (BeautiBond Multi, BBM), Group 2: two-step SEA application (FL-Bond II, FLBII). Microshear bond strengths (µSBS) were measured 24-h after bonding for each of the post-bleaching time periods. Acid-base resistant zones (ABRZs) were observed under SEM. Data were analyzed using three-way ANOVA. Bleaching caused a significant decrease of the immediate µSBSs for both adhesives (p≤0.005) then increased. Thick ABRZs were observed in BBM and FLBII after bleaching. Enamel µSBSs were adversely affected by bleaching. Thick ABRZ was created with bleaching.