Effect of different concentrations of chlorhexidine on bond strength of primary dentin

The purpose of this study was to assess the effect of different concentrations of chlorhexidine digluconate on the bond strength to primary tooth dentin immediately and after 12 months.

Twenty-one sound primary molars were assigned to 3 groups (N=7). The bonding procedure was performed in control group (A) using 37% phosphoric acid gel (15 seconds), then washed (15 seconds), dried with air (30 seconds), and rehydrated with water. Groups B and C had the rewetting procedure performed, respectively, with 0.5% and 2% chlorhexidine for 30 seconds. The tensile bond strength was tested immediately (IM) or after storage in artificial saliva for 12 months (12M). Data were evaluated by 2-way repeated measures analysis of variance and Tukey's post-hoc test.

There was no significant reduction in bond strength values when chlorhexidine was used at concentrations of 0.5% (IM=49.3/2.6 and 12M=32.3/7.9) and 2% (IM=44.0/8.7 and 12M=34.6/5.1). Conversely, a significantreduction in bond strength was observed in the control group (IM=50.8/12.8 and 12M=20.4/3.7).

The study validates the concept that chlorhexidinesolution, at different concentrations, may prevent the degradation of the adhesive interface in primary teeth.