Methods:
CHX (0, 0.5, 1, 2, 5 and 10 wt%) was added into composite by hand spatulation. The mix was then poured into metallic moulds (10 mm diameter and 1 mm thickness) and light cured for 40 second. The degree of monomer conversion (DC%) was determined by ATR-FTIR (n=10). Antibacterial activity against three cariogenic bacterial species (S.mutans, L.casei and A.naeslundii) was assessed using agar diffusion assay. Data analysis was performed by ANOVA and Tukey's (p<0.05). Results: ANOVA revealed no significant differences in DC% of samples containing 0, 0.5 and 1 wt% (average DC% was 53±2 [mean±SD]). On raising CHX concentration from 2 to 10 wt%, DC% was significantly reduced (p<0.05). The average DC% for samples containing 2,5 and 10% was 47±1, 42±2 and 33±2, respectively. In agar diffusion test, only composites containing CHX showed antibacterial effect. The size of inhibition zones was substantially enhanced upon increasing CHX concentration from 0.5 to 2%.
Conclusion: The results of this study suggest that incorporation of 1 % CHX to dental composite is optimal for an effective bacterial inhibition with appropriate degree of conversion.