RESUMO
The purpose of this blind study was to determine the effect of a two-stage chlorhexidine varnish, after three months, on the gingival status of 11- to 15-year-old children attending a school in Rio de Janeiro, Brazil. Subjects participating in the study were randomly allocated to control (C) and treatment (T) groups, n = 53 and n = 57, respectively. All subjects were matched at baseline on age, salivary levels of mutans streptococci, and caries scores. After elimination of carious lesions, a prophylaxis was given to both groups. The chlorhexidine varnish was then painted on the entire dentition of Group T subjects only. Prior to caries elimination, and again after three months, the gingival index was used to assess the gingival status of study subjects. An average of 106.6 +/- 8.9 and 107.7 +/- 6.2 gingival sites per subject (four sites per tooth) in Groups C and T, respectively, were examined by the same calibrated examiner on two occasions. For statistical purposes, data were dichotomized [(0,1) (2,3)] for the gingival index. Independent t-tests and paired t-tests were used to analyze the data. The percentage of sites per subject with scores of two or three at the baseline were balanced between study groups (3.7 +/- 7.1 for T; 1.8 +/- 3.2 for C; p = 0.08). After three months, a statistically significant decrease in the average percentage of sites with scores of two or three was demonstrated in the T group (0.7 +/- 2.4, T, p < 0.0001; 1.3 +/- 3.0, C, p < 0.25). The authors concluded that the application of a chlorhexidine varnish significantly improved the gingival health of T subjects for up to three months. A significant improvement in the gingival health could not be demonstrated in the C group.