RESUMEN
Three hundred and fifty three [353] school children aged 12 years in Cairo were included in the study. They were examined for detection of proximal caries clinically and radiographically by using bite wing films. The children were divided into three groups: [1] cholorhexidine gel group [n=121], [2] placebo group [n=117], and control group [n=115]. After 3 years, the mean proximal caries increment [new DFS] was 2.23 in the chlorhexidine, 4.31 in the placebo gel group and 5.14 in the control group. The difference between the chlorhexidine gel and either of placebo and control group was statistically significant [P < 0.05 and P < 0.001 respectively]. The number of new proximal fillings s] was 0.31, 0.93 and 1.12 in chlorhexidine, placebo and control groups respectively