The Relationship between Anticaries Activity of Monofluorophosphate Dentifrices and Their Performances in Laboratory Tests

Abstract

The uptake of fluoride by enamel mineral to form alkali-insoluble fluoridated hydroxyapatite (FHA) was measured following pretreatment of hydroxyapatite powder with soluble extracts of 8 sodium monofluorophosphate dentifrices and 1 control (non-fluoride) dentifrice under conditions relevant to normal dentifrice usage. The ability of slurries of these toothpastes to reduce the acid dissolution rate of compressed discs of hydroxyapatite was also measured in the laboratory employing similar pretreatment conditions. These 2 laboratory measurements for each dentifrice were compared with their anticaries clinical efficacies calculated as the percentage reduction in the decayed and filled surfaces (DFS) increment when compared with the corresponding control dentifrice treatment. The DFS increments had been previously determined in 4 separate, double-blind clinical trials lasting 30–36 months, by examiners who had demonstrated close agreement between their independent findings. A Spearman product-moment correlation coefficient, γ, of 0.89 was observed (p < 0.01) with results from the FHA technique and a correlation, r, of 0.95 (p < 0.001) with results from the reduction in dissolution. Using the Kendall rank correlation method, a coefficient, τ, of 0.67 was obtained (p < 0.02) with the FHA technique, and of 0.81 (p < 0.002) with the disc dissolution technique. The correlation coefficients suggested that the measurement of these 2 parameters, when carried out under conditions similar to those experienced at the tooth surface during normal brushing procedure, is of value in predicting the anticaries efficacy of dentifrices.

A safety study in vitro for the effects of an in-office bleaching system on the integrity of enamel and dentine

“…The toothpaste was a 3 g in 10 ml water slurry, to simulate dilution during brushing. 27 Hardness testing Ten enamel and 10 dentine specimens prepared as before were glued on to circular acrylic discs designed to fit onto the suction cup of a hardness indenter (Wallace and Co Ltd, Unit 4 St Georges Industrial Estate, Richmond Road, Kingston, Surrey UK).…”