Abstract
An in vitro model of periodontopathic bacteria biofilm was established and the killing activity of various gargles including povidone-iodine gargle (PVP-I) determined with this model. Actinobacillus actinomycetemcomitan Y4 (ATCC 43718) biofilm was formed by culturing this strain on polycarbonate membrane (PCM). Similarly, mixed biofilms of A. actinomycetemcomitans Y4, Streptococcus oralis ATCC 10557, and Fusobacterium nucleatum ATCC 25586 were formed (co-aggregation) by culturing a mixture of these strains on PCM. Exposure of the A. actinomycetemcomitans biofilm formed by culturing for one day or three days to 0.23% PVP-I for 3 min reduced the count of viable cells by-3.59 and -3.39 (Δlog10CFU/mL), respectively. The killing activity of PVP-I was stronger than those of 0.02% benzethonium chloride (BEC) and 0.002% chlorhexidine gluconate (CHG). Repeated exposure of this biofilm to 0.23% PVP-I (for 1 min, 3 times a day for 5 consecutive days) reduced the count of viable cells on the 5th day by -4.85 in the biofilm formed by one day culture and -3.55 in the biofilm formed by three day culture (Δlog10CFU/mL).
Exposure of the mixed biofilm containing A. actinomycetemcomitans, S. oralis and F. nucleatum cultured for one day to 0.23% PVP-I for 3 min reduced the count of viable cells by <-3.00, -2.31, and <-1.50 (Δlog10CFU/mL), respectively. The killing activity of PVP-I against the mixed biofilm was stronger than those of 0.02% BEC and 0.002% CHG. PVP-I is very effective against periodontopathic bacteria biofilms.
