[Two-year trial of the fluoride-containing varnishes Duraphat and Carex].

Previous studies have shown that topical application of the fluoride varnish Duraphat reduces caries incidence. The aim of the present study was to compare the caries inhibiting effect of a new fluoride varnish (Carex) containing 1.80% fluoride (F) with that of Duraphat (2.26%F). Informed consent was obtained from the guardians of 495 10-12-years-olds in Voss Dental Health District (low F area). The children were randomly allocated to two groups. One group of subjects received six-monthly applications of Duraphat (n = 206), the other Carex (n = 189). Ethical considerations precluded the use of a placebo varnish. All participants received dental examinations including one pair of posterior bitewing radiographs and necessary dental care annually. One trained examiner interpreted bitewing radiographs blindly. Total mean 2-year net DFS increment for 24 posterior approximal surfaces was 1.79 (s = 3.12) in the Duraphat group and 1.53 (s = 2.92) in the Carex group, a difference which was non-significant (P greater than 0.40). Thus it seems that Carex and Duraphat have approximately the same caries-preventive effect on posterior approximal surfaces.