Progression of approximal caries in primary molars and the effect of Duraphat treatment

The progression of caries lesions over a 2-yr period was studied in 3-6-yr-olds. All 468 children included in the study lived in an area during 1977-85 (Malmö, Sweden) with a low fluoride concentration (0.2 ppm) in the drinking water. Radiographs were taken with a standardized periodic identical technique. Caries lesions were scored on the distal surface of the first and on the mesial surface of the second primary molars (maximum 8 per child) according to Gröndahl et al. Half of the children were treated semiannually with a fluoride varnish (Duraphat). In all, 421 surfaces with caries at baseline were available at the 1-yr examination and 369 at the 2-yr examination. After 1 yr, 34.1% of the shallow enamel lesions remained unchanged, while a progression was seen in 60.9%. 5.1% had been restored. The corresponding figures after 2 yr were 20.6, 52.1 and 27.3%. Of the deeper enamel lesions at baseline, 28.8% remained unchanged after 1 yr and 13.7% after 2 yr. Of the lesions extending into the dentin, 81.5% had been restored after 1 yr and all after 2 yr. When evaluating the effect of Duraphat, only the percentage of individuals with one or more superficial enamel lesions showing progression was determined. After 1 yr, 51.2% in the Duraphat (n = 41) and 82.8% in the control group (n = 29) showed progression (restored surfaces included). The corresponding figures after 2 yr were 66.7 (n = 42) and 91.2% (n = 34). The differences after both 1 yr and 2 yr were statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)