Effect of chlorhexidine incorporation into a self-etching primer on dentine bond strength of a luting cement

Objectives

This study investigated the effect of incorporating chlorhexidine in a self-etching primer on the bond strength of an adhesive resin cement to dentine and on antibacterial activity.

Methods

Experimental self-etching primers were prepared by adding chlorhexidine (CHX) diacetate to ED primer 2.0 (Kuraray Medical Inc.) to obtain chlorhexidine concentrations of 1.0 wt% and 2.0 wt%. Human occlusal dentine surfaces were conditioned for 30 s using the experimental primers or pure ED primer. Composite blocks were luted using Panavia F 2.0 (Kuraray Medical Inc.). After storage in water for 24 h, the bonded teeth were sectioned into 0.9 mm × 0.9 mm beams and stressed to failure in tension to examine microtensile bond strength (μTBS). Fractured surfaces were examined with a field-emission scanning electron microscopy (FE-SEM). The morphology of dentine surfaces that were conditioned with each primer was also observed under FE-SEM. An agar diffusion test was performed to examine the antibacterial effect of each primer against Streptococcus mutans and Enterococcus faecalis.

Results

Addition of chlorhexidine to the primer had significant effects (p < 0.001) on μTBS and antibacterial effect. No significant difference in μTBS was found between the groups that contained 0% and 1% chlorhexidine in the primer (p = 0.095). Conversely, the group that contained 2% chlorhexidine showed significantly lower μTBS and pronounced cohesive failures within the thin layer of the primer.

Conclusions

Incorporation of chlorhexidine into ED primer 2.0 showed significant antibacterial activities. Conditioning with the 1% chlorhexidine-containing primer had no adverse effect on μTBS.