Effectiveness of silver diamine fluoride and sodium fluoride varnish in arresting dentine caries

of thesis entitled Effectiveness of silver diamine fluoride and sodium fluoride varnish in arresting dentine caries submitted by Chu Chun Hung for the degree of Doctor of Philosophy at the University of Hong Kong in May 2004 Introduction: Caries prevalence in young children in China is high and most of the decayed teeth are left untreated. Conventional dental treatments are either not available or are unaffordable in many rural areas. Innovative approaches are needed to improve this situation. Aim: This prospective clinical trial investigated the effectiveness of topical fluoride applications in arresting dentine caries. The first null hypothesis to be tested was that there were no differences in the effectiveness of applying a 38% silver diamine fluoride (SDF) solution (44,800 ppm F), a 5% sodium fluoride (NaF) varnish (22,600 ppm F) and water in arresting dentine caries. The second null hypothesis was that caries removal prior to fluoride application had no impact on its effectiveness in arresting dentine caries. Methods: A total of 375 Chinese kindergarten children, aged 3-5 years with carious upper anterior teeth were divided into five groups. Children in the first and second groups received annual applications of SDF. NaF 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 with hand instruments prior to fluoride application at the baseline examination. The fifth group of children received annual applications of water. Follow-up examinations were performed every six months. The children’s parents completed a questionnaire to assess parental satisfaction with the appearance of the upper anterior teeth of their child before treatment and again at 24 months after treatment. Results: A total of 308 children were followed for 30 months. The respective mean numbers of arrested caries tooth surfaces in the five groups of children were 2.5, 2.8, 1.5, 1.5 and 1.3 (p<0.001). Results showed that children receiving SDF had more caries arrested than other children after 30 months. There was no significant difference in caries arrest between children with caries removal before fluoride treatment and those who had not received this treatment. These results supported the second but not the first null hypothesis. Children in the control group developed more new caries lesions than children receiving SDF and NaF varnish after 30 months (p<0.001). There were no significant differences in the increment of non-vital teeth between the children groups. No discoloration or damage to the gingival tissues were observed. Conclusion: Silver diamine fluoride was found to be effective in arresting dentine caries in primary anterior teeth in preschool children. Topical application of 5% sodium fluoride varnish every 3 months produced no evidence in support of an effect in arresting dental caries in primary anterior teeth in preschool children. There was no evidence to show that removal of carious tissue prior to application of fluoride agents had an effect on the ability to arrest dentine caries. (450 words)