Two-year study on the effect of professional toothcleaning on schoolchildren in Oppegård, Norway.

A longitudinal study on the effect of a preventive program based on bimonthly professional toothcleaning and hygiene instruction was carried out on 293 schoolchildren from the 1st, 4th and 7th grades. The prophylactic paste used contained 0.8% sodium monofluorophosphate. The control groups brushed with a 0.2% sodium fluoride solution four to five times during each school year. After 2 years the Visible Plaque Index and the Gingival Bleeding Index were significantly reduced for all grades in the test groups as compared to the controls. The percentage of children without new caries lesions increased significantly from an average of 50% in the control to 71% in the test group. The mean caries increments during the 2 years, excluding occlusal surfaces, were 0.22, 0.28 and 1.20 in the three test groups. This represents an average caries reduction of 65%, compared to the control group. The increment reductions reached borderline significance, using the chi-square test.