A clinical trial of two fluoride dentifrices in an area of low caries prevalence.

OBJECTIVE

The study was designed to test the hypothesis that a dentifrice with fluoride at the same concentration (1000ppm) from two sources, ie NaF and NaMFP, would provide a greater treatment effect than one with NaMFP alone.

BASIC RESEARCH DESIGN

A double blind clinical trial with random assignment of children to one of two groups was carried out for three years. The two trial groups were similar at the outset in respect to those variables which might otherwise have affected the outcome, including age and gender, with means per subject of 98.4 sound surfaces and 2.2 decayed and filled surfaces in each group initially.

CLINICAL SETTING

Secondary schools in the Isle of Wight, UK, an area of diminished caries experience.

PARTICIPANTS

One thousand six hundred and thirty-three children aged initially 10-12 years.

INTERVENTIONS

A test dentifrice containing 500ppm NaF plus 500ppm NaMFP, and a standard active control product containing 1000ppm NaMFP. Products were used in the home.

OUTCOME MEASURES

Increment of DF teeth and surfaces measured over 36 months.

RESULTS

After three years, mean approximal surface increments were 3.6 new DFS in the control group and 3.1 in the test group, a difference 13 per cent (P < 0.05). Thirty-four per cent of the subjects were caries free at the outset. In the 1075 subjects with caries at the outset, the total mean increment on all surfaces was 7.2 new DFS in the control group and 6.4 new DFS in the test group, a difference of 11 per cent (P < 0.05). However, those subjects with initial caries had approximal surface increments of 4.8 new DFS in the control group and 4.0 new DFS in the test group, a difference of 16 per cent (P < 0.01). Included separately along with the conventional rubric were enamel white spots on which no differential treatment effect was observed.

CONCLUSIONS

Under the conditions of this study, the regular use of a dentifrice containing 1000ppm fluoride from two sources provided a significantly greater treatment effect than one with fluoride from a single source.