Bond strength to eroded dentin as per chlorhexidine use for controlling erosive wear or interface aging: an 18-month assay

Abstract

The aim of this study was to assess the effect of a chlorhexidine digluconate solution (CHX) applied as an antiproteolytic agent for controlling erosive tooth wear or as part of the adhesive treatment on long-term bond strength to eroded dentin. Dentin specimens were abraded with a 600-grit silicon carbide (SiC) paper for 1 min (sound dentin - S), subsequently treated with 2% CHX for 1 min (with excess removed, followed by a 6-hour rest), and eroded by exposure to Coca-Cola for 5 min, three times a day, for 5 days (CHX-treated and eroded dentin - CHXE), or only eroded (eroded dentin - E). The specimens were acid-etched (15 s), rinsed (30 s), dried (15 s), and rehydrated with 1.5 μL of distilled water for 1 min, with excess removed (control - S.C/CHXE.C/E.C) or 2% CHX (S.CHX/CHXE.CHX/E.CHX). Adper Single Bond 2 was scrubbed twice on the surface for 15 s each and then light-cured for 10 s, and resin composite cores were built up. Specimens were sectioned into beams and microtensile bond strength was tested (μTBS; 0.5 mm/min) immediately or after 18-month aging. Failure modes were analyzed using a digital microscope. Data (μTBS/MPa) were analyzed by three-way ANOVA, followed by Tukey's test (α = 0.05). μTBS to E and CHXE, irrespective of the rehydration solution and aging period, were equivalent to each other and lower than that to S. CHX as the rehydration solution reduced immediate and long-term µTBS to S. Aging reduced μTBS. By controlling tooth wear or interface aging, CHX could not influence long-term bonding to eroded dentin.

Figure. Experimental design: A) Third molars were obtained and exposed dentin was B) abraded with 600-grit SiC paper for 1 min (sound dentin - S), C) subsequently treated with 2% CHX for 1 min (excess removal, and 6-hour rest) and D) eroded by Coca-Cola for 5 min, three times a day, for 5 days (CHX-treated and eroded dentin - CHXE), or only eroded (eroded dentin - E). The specimens were then E) acid-etched (15 s), rinsed (30 s), dried (15 s), and F) rehydrated with 1.5 μL of distilled water (control - S.C/CHXE.C/E.C) or 2% CHX (S.CHX/CHXE.CHX/E.CHX), followed by G) excess removal. H) Adper Single Bond 2 was scrubbed twice on the surface for 15 s each, and light-cured for 10 s, and I) resin composite cores were built up. J) Specimens were sectioned into beams, and K) microtensile bond strength was tested (μTBS; 0.5 mm/min) immediately or after 18-month aging. L) Failure modes were analyzed using a digital microscope.