Effects of mouthrinses with triclosan, zinc ions, copolymer, and sodium lauryl sulphate combined with fluoride on acid formation by dental plaque in vivo

Bacteriological tests demonstrated a slight synergistic effect of triclosan and sodium lauryl sulphate (SLS) on the growth of Streptococcus mutans NCTC 10449 and Streptococcus sanguis ATCC 10556 in vitro. A single mouthrinse with SLS (17.4 mM) or SLS plus triclosan (3.5 mM) significantly decreased the number of salivary mutans streptococci in a group of 12 subjects up to 90 min after rinsing. The effect on plaque pH of a mouthrinse with either 12.0 mM NaF, NaF plus 10.0 mM zinc acetate, NaF plus 17.4 mM SLS, or NaF plus SLS plus 3.5 mM triclosan with or without the addition of zinc ions or 0.65% w/v of a polyvinylmethyl ether/maleic acid copolymer was investigated. The plaque pH responses to a 10% w/v sucrose mouthrinse were measured in 2-day-old plaque with microtouch pH electrodes in six groups of 10 subjects 90 min after a single mouthrinse with test solution. There was no significant difference in plaque pH between the various mouthrinses. In conclusion, triclosan enhanced the growth-inhibitory activity of SLS against oral streptococci in vitro but not against salivary mutans streptococci in vivo. Neither triclosan incorporated into a mouthrinse containing SLS plus fluoride, nor the addition of zinc ions or copolymer affected acid formation by dental plaque in vivo.