Approximal caries increment in two cohorts of schoolchildren after discontinuation of a professional flossing program with chlorhexidine gel.

We have in two earlier studies evaluated the effect of professional flossing with chlorhexidine (CHX) gel treatment, in 4- to 7-year-old preschool children and in 12- to 15-year-old teenagers. The mean caries reduction after 3 years was around 40% compared to placebo gel or no gel treatment. The aim of the present investigation was to follow up these two clinical studies. The preschool children were followed up to the age of 16 years and the teenager group to the age of 19. Of the total number of original children, 71 and 80% were available at the age of 16 and 19 years, respectively. At the 9-year follow-up, when the children were 16 years old, the former CHX group had still significantly lower mean DFS than the control group (p < 0.05). The differences in caries increment occurred between 7 and 12 years of age, whereas the number of new caries lesions during the next 4 years were almost the same in the three groups. At the 4-year follow-up, when the teenagers were 19 years old, DFS was 6.9 in the former CHX group compared to 10.4 in the control group (p < 0.05). The main conclusion of these two follow-up studies after 9 and 4 years, respectively, is that caries reductions obtained at the end of professional flossing with a 1% CHX gel were maintained.