Effectiveness of SDF in arresting root caries in different fluoridated areas

Abstract

OBJECTIVES: To compare the effectiveness of annual application of silver diammine fluoride (SDF) solution on arresting root caries in community-dwelling elders living in water fluoridated and non-fluoridated areas. METHODS: This study was conducted in a water fluoridated area (Hong Kong, HK) and also in a non-fluoridated area (Guangzhou, GZ). Healthy community-dwelling elders who had at least 5 teeth with exposed root surfaces and not indicated for extraction were recruited and randomly allocated into one of two groups: Gp1 (placebo control) – annually application of soda water; Gp2 (test) – annual application of a 38% SDF solution. Individual oral hygiene instruction and fluoridated toothpaste was provided to all subjects. The status of dental root surfaces were clinically examined by calibrated examiners at baseline and every 6 months. RESULTS: A total of 533 elders with 138 root surfaces with active caries lesion were recruited at baseline, 260 elders with 84 active root caries lesions in HK and 273 elders with 54 active root caries lesions in GZ, respectively. After 18-months, 75 (54%) of these lesions were reviewed, 51 and 24 in HK and GZ, respectively. The proportions of active lesions that had become arrested were 32% and 75% in Gp1 and Gp2 in HK (X2 test, P<0.05), and 11% and 87% in Gp1 and Gp2 in GZ (X2 test, P<0.05), respectively. The difference in caries arrest rates in the SDF groups in HK and in GZ were not statistically significant (X2 test, P>0.05). CONCLUSIONS: Based on the 18-month result, it is concluded that the annual application of 38% SDF solution can arrest root caries in community-dwelling elders. Furthermore, background water fluoride level does not have a statistically significant influence on the effectiveness of SDF. This clinical trial is still ongoing and longer-term results will be reported later.