The incorporation of chlorhexidine in a two-step self-etching adhesive preserves dentin bond in vitro

Abstract 

Objectives

To investigate whether the incorporation of chlorhexidine in a two-step self-etching adhesive can preserve dentin bond strengths.

Methods

Different amounts of 20% chlorhexidine digluconate were added directly to the primer of Clearfil SE Bond to prepare mixtures of four different concentrations of chlorhexidine: 0.05%, 0.1%, 0.5% and 1.0%. Sixteen extracted third molars were randomly divided into 4 groups. Each group corresponded to one of the four chlorhexidine concentrations. Each of the 16 teeth was sectioned into two halves. One half was bonded with Clearfil SE Bond without chlorhexidine, and the other half was bonded with Clearfil SE Bond containing different concentrations of chlorhexidine. Specimens were stored in 0.9% NaCl containing 0.02% sodium azide at 37°C. Microtensile bond strengths were tested 24h after specimen preparation or 12 months later. The modes of fractures were examined under a stereomicroscope.

Results

Twelve-month storage resulted in significant bond strength reduction of all control groups (p<0.05). When incorporated in SE Bond primer, chlorhexidine preserved dentin bond in the 0.1%, 0.5% and 1.0% chlorhexidine group (p<0.05); in the 0.05% group, there is no statistical difference of bond strength between control group and experimental group tested at the 12-month period (p>0.05).

Conclusions

When incorporated in the primer of Clearfil SE Bond, chlorhexidine can preserve dentin bond as long as the concentration of chlorhexidine in the primer is higher than or equal to 0.1%.

Keywords: Chlorhexidine, Bond degradation, Matrix metalloproteinases, Self-etching adhesives, Microtensile bond test