Anti-calculus effects of dentifrice containing pyrophosphate compared with control.

A 3-month, double-blind, randomized, longitudinal, parallel clinical study was conducted to compare the effects on supragingival calculus deposits of a dentifrice containing soluble pyrophosphate to a control MFP dentifrice, which did not contain pyrophosphates. During the pre-test phase, 247 teachers were examined for presence of calculus on the lingual surfaces of the 6 lower anterior teeth, using the Periodontal Probe Method of Calculus Assessment (Volpe et al. 1965). Statistical methods employed were the two-way analysis of variance as well as the paired and unpaired t tests. The level of statistical significance chosen was p less than 0.05. At the end of the 3-month pre-test phase, 88 candidates with the highest calculus index scores met the initial criteria and were stratified into two balanced groups based on their age and sex. Each group received an oral prophylaxis and participants were assigned to use either the dentifrice containing the pyrophosphate or the MFP and instructed to brush their teeth twice daily at home for the next 3 months (test phase). The results showed that the group using the pyrophosphate dentifrice experienced a 20% greater reduction in calculus formation when compared to the MFP control There was also a greater number of calculus-free subjects and tooth surface sites in the soluble pyrophosphate group. The change in the Volpe-Manhold Index revealed significant differences for both the pyrophosphate group (change = 1.7111; p = 0.0010) as well as, though less prominent, for the control group (change = 1.4186; p = 0.0313).