A 6-month, double-blind, parallel and unsupervised clinical study was conducted to compare the effects on supragingival calculus formation of a dentifrice containing 0.3% triclosan and 2.0% of a copolymer in a 0.243% sodium fluoride/silica base, as compared to a placebo dentifrice containing 0.243% sodium fluoride in a silica base. Subjects were initially stratified into two balanced groups based on their Volpe-Manhold calculus index scores that were obtained from a 3-month pre-test period using a placebo dentifrice. All subjects received an oral prophylaxis and were assigned to the use of either the fluoride/triclosan/copolymer dentifrice or the placebo dentifrice. Seventy adult male and female subjects completed the entire 6-month study. The results after 3-months' use of their respective dentifrices indicated that the subjects using the fluoride/triclosan/copolymer dentifrice had 26.34% less supragingival calculus formation than the subjects using the placebo dentifrice. This reduction in supragingival calculus was significant at the 99% level of confidence. The results after 6 months indicated that the subjects using the fluoride/triclosan/copolymer dentifrice had 36.27% less supragingival calculus formation than the subjects using the placebo dentifrice. This reduction was significant at the 99% level of confidence.