Methods: We evaluated 2 commercial products: GC Tri Plaque ID Gel (TPID, GC) and 2tone Disclosing Solution (2tone, Young Dental). To form biofilm in vitro, Streptococcus mutans ATCC25175 was anaerobically grown at several conditions on 24 well plates. The surface pH and volume of biofilm was measured. After staining treatment of biofilm by disclosing products, a photograph of the stained biofilm was taken using a digital camera to analyze color of biofilm. The photograph was analyzed with image analysis software (WinROOF, MITANI CORPORATION). The color of stained biofilm was divided into red, blue and light blue according to preliminary established threshold, and rate of varied color region on biofilm was determined. The data was statistically analyzed (ANOVA, Turkey’s).
Results: We could separate 3 colors on stained biofilm with software. Thin and neutral pH biofilm stained by TPID and 2tone showed red color (no significant). TPID indicated significantly higher light blue color rate (72%, p<0.01) on thick and low pH biofilm. On the other hand, 2tone did not show light blue color.
Conclusions: We could analyze objectively in vitro biofilm staining ability. Thick biofilm was stained light blue under low pH by TPID. This study suggested TPID may be more useful product to find several different region of dental plaque depending on condition such as thickness or pH than 2tone.