IN-VITRO STUDIES OF THE EFFECT OF ANTISEPTIC-CONTAINING MOUTHWASHES ON THE FORMATION AND VIABILITY OF STREPTOCOCCUS-SANGUIS BIOFILMS

The aims of this study were to evaluate the growth of Streptococcus sa nguis on hydroxyapatite, bovine enamel and polytetrafluoroethylene sub strata in a constant depth film fermenter, and to determine the effect s of three antimicrobial-containing mouthwashes on biofilm formation a nd bacterial viability on hydroxyapatite and enamel. There was little difference in the final cell density (5 x 10(4) cfu mm(-2)) of the Str ep, sanguis biofilm on the three substrata. When hydroxyapatite-grown biofilms were exposed to the mouthwashes for 1 min, the one containing triclosan (T) proved the most effective. The chlorhexidine-containing mouthwash (CX) also achieved significant kills. The T-containing mout hwash was the most effective at killing biofilms grown on enamel. Pre- treatment of hydroxyapatite with CX, cetylpyridium chloride (CPC) or T for 1 min resulted in undetectable biofilm formation after 8 h. After 8 h of growth, only biofilms grown on enamel discs pre-treated with C X showed a reduction in the number of viable organisms. In conclusion, the results of this study have shown that while growth of Strep. sang uis on hydroxyapatite and enamel were similar, the ability of antimicr obial agents to prevent the accumulation of viable bacteria depended o n the nature of the substratum.