Abstract

In this study, 48 human teeth were chosen; they were extracted from natural sources. Sound dentin surfaces were exposed by operating low speed diamond disc at conventional speed with copious water spraying. The teeth were divided by randomizing technique, into two equal groups (n = 24): the control and the test group. Teeth in the control group followed the conventional method of etching, washing, applying adhesive, while teeth from the test group followed an intermediate stage of the application for 60 s of 2% chlorhexidine solution before applying adhesive system (Prime and Bond NT). After applying the adhesive, all the teeth received a standard cylindrical light curing composite restoration. Half of the teeth of each group were subjected to the bonding strength tests after 24 h and the other half, after 4 months period of keeping in distilled water at 37°C. The results show that there are no significant statistical differences at 24 h between the two groups while after 4 months, there was a positive statistical significance in favor of the group which followed a subsequent treatment with chlorhexidine. The application of 2% chlorhexidine might prevent hybrid layer degradation and this procedure has a beneficial effect on maintaining bond strength.

Key words: Teeth, chlorhexidine, matrix metalloproteinases, bond strength.