A 3-YEAR CLINICAL-TRIAL OF A COMBINATION OF TRIMETAPHOSPHATE AND SODIUM-FLUORIDE IN SILICA TOOTHPASTES

The relative efficacy of NaF silica toothpastes containing 1000 ppm fl uoride and 1500 ppm fluoride in the control of dental caries is not cl ear-cut. Also, it has not been established that incorporation of trime taphosphate (TMP) improves the anticaries activity of NaF toothpastes. A three-year clinical trial was conducted to test the hypotheses that : (i) the anticaries activity of NaF toothpastes containing 1500 ppm F was greater than that of NaF toothpastes containing 1000 ppm F, and ( ii) inclusion of TMP improved the efficacy of NaF silica pastes. Subsi diary aims included determination of whether frequency of toothbrushin g and method of rinsing after brushing were correlated with caries inc rements. The study involved 4196 children aged 11 to 12 years at outse t. These participants had been selected from a pool of 7374 potential subjects on the basis of caries experience and dental eruption pattern . They were stratified by sex, examiner, and presence of calculus and caries, and were allocated at random to one of the four toothpastes un der study. Using mirror and probe and also FOTI, we carried out clinic al examinations at baseline and annually thereafter for 3 yrs. Bitewin g radiographs of a subset of children were taken at baseline and at th e end of the study. The outcome measure for the study, DMFS increment, was defined as the increase in caries over 3 yrs, taking into account changes occurring on individual tooth surfaces. Data for 3467 subject s were available for analyses at both baseline and year 3 examinations . Radiographs were taken for 1942 subjects at both baseline and year 3 examinations. The mean three-year clinical-only DMFS increment for th e subjects using 1500-ppm-NaF pastes was 3.93, which was 6% lower than the corresponding mean of 4.19 for the 1000-ppm-NaF pastes. There was no significant difference between the mean DMFS increment for those u sing paste with or without TMP. Subjects who claimed to brush more fre quently or who claimed not to use a tumbler to rinse after toothbrushi ng had lower three-year DFMS increments.