Ar. Biesbrock et al., Relative anti-caries efficacy of 1100, 1700, 2200, and 2800 ppm fluoride ion in a sodium fluoride dentifrice over 1 year, COMM DEN OR, 29(5), 2001, pp. 382-389
There is limited evidence from clinical trials on the dose response of sodi
um fluoride dentifrices at concentrations above 1100 ppm fluoride ion, with
respect to caries efficacy This randomized, double-blind study examined th
e anticaries effectiveness of sodium fluoride dentifrices containing 1700 p
pm, 2200 ppm. and 2800 ppm fluoride ion relative to an 1100 ppm fluoride io
n 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 radio
graphic examination at baseline and after 1, 2, and 3 years of using the so
dium fluoride dentifrices. Subjects were stratified according to gender, ag
e and baseline DMFS scores derived from the visual-tactile baseline examina
tion and randomly assigned to one of four treatment groups: 0.243% sodium f
luoride (1100 ppm fluoride ion), 0.376% sodium fluoride (1700 ppm fluoride
ion), 0.486% sodium fluoride (2200 ppm fluoride ion), and 0.619% sodium flu
oride (2800 ppm fluoride ion). All products were formulated with the same f
luoride compatible silica abrasive. Results after 1 year provided evidence
of a positive sodium fluoride dose response. Compared to the 1100 ppm fluor
ide treatment group, the 1700 ppm fluoride treatment group had an 11.0% red
uction in DMFS that was not statistically significant, while the 2200 ppm a
nd 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 dif
ference observed between treatments were substantially less and failed to r
each statistical significance (P <0.05). Collectively, the data demonstrate
that the 2200 ppm and the 2800 ppm fluoride treatments delivered statistic
ally significantly greater caries efficacy than the 1100 ppm. fluoride trea
tment. This large-scale clinical trial provides evidence of a positive stat
istically significant dose relationship between dental caries and sodium fl
uoride in a dentifrice at levels above 1100 ppm. fluoride at year 1.