Dental caries in Chinese pre-school children is common, and restorative treatment is not readily available. This prospective controlled clinical trial investigated the effectiveness of topical fluoride applications in arresting dentin caries. We divided 375 children (aged 3-5 yrs) with carious upper anterior teeth into five groups. Children in the first and second groups received annual applications of silver diamine fluoride solution (44,800 ppm F). NaF varnish (22,600 ppm F) was applied every three months onto the lesions of children in the third and fourth groups. For children in the first and third groups, soft carious tissues were removed prior to fluoride application. The fifth group was the control. We followed 341 children for 18 months. The mean numbers of new caries surfaces in the five groups were 0.4, 0.4, 0.8, 0.6, and 1.2, respectively (p = 0.001). The respective mean numbers of arrested carious tooth surfaces were 2.8, 3.0, 1.7, 1.5, and 1.0 (p < 0.001).