Relative anti-caries efficacy of 1100, 1700, 2200, and 2800 ppm fluoride ion in a sodium fluoride dentifrice over 1 year.

There is limited evidence from clinical trials on the dose response of sodium fluoride dentifrices at concentrations above 1100 ppm fluoride ion, with respect to caries efficacy. This randomized, double-blind study examined the anti-caries effectiveness of sodium fluoride dentifrices containing 1700 ppm, 2200 ppm and 2800 ppm fluoride ion relative to an 1100 ppm fluoride ion control. A population of 5439 elementary schoolchildren, aged 6-15 years, was recruited from an urban central Ohio area with a low fluoride content water supply (<0.3 ppm). Subjects were examined by visual-tactile and radiographic examination at baseline and after 1, 2, and 3 years of using the sodium fluoride dentifrices. Subjects were stratified according to gender, age and baseline DMFS scores derived from the visual-tactile baseline examination and randomly assigned to one of four treatment groups: 0.243% sodium fluoride (1100 ppm fluoride ion), 0.376% sodium fluoride (1700 ppm fluoride ion), 0.486% sodium fluoride (2200 ppm fluoride ion), and 0.619% sodium fluoride (2800 ppm fluoride ion). All products were formulated with the same fluoride compatible silica abrasive. Results after 1 year provided evidence of a positive sodium fluoride dose response. Compared to the 1100 ppm fluoride treatment group, the 1700 ppm fluoride treatment group had an 11.0% reduction in DMFS that was not statistically significant, while the 2200 ppm and 2800 ppm fluoride treatment groups showed statistically significant (P<0.05) reductions of 18.6% and 20.4%, respectively. The reductions in caries delivered by the higher fluoride dentifrices were present across all tooth surface types, but were most pronounced for occlusal surfaces. Results at years 2 and 3 were confounded by a concurrent fluoride rinse program, which involved portions of the study population. While the trends for the higher fluoride dentifrices observed at year 1 remained at years 2 and 3, the difference observed between treatments were substantially less and failed to reach statistical significance (P<0.05). Collectively, the data demonstrate that the 2200 ppm and the 2800 ppm fluoride treatments delivered statistically significantly greater caries efficacy than the 1100 ppm fluoride treatment. This large-scale clinical trial provides evidence of a positive statistically significant dose relationship between dental caries and sodium fluoride in a dentifrice at levels above 1100 ppm fluoride at year 1.

RCT Entities:   Population Interventions Outcomes