Nano Silver Fluoride for preventing caries.

DESIGN: Randomised controlled trial, double blind, in a community setting.

INTERVENTION: School children with active caries in primary teeth and no pulpal exposure, fistula or decay in permanent teeth were chosen. Caries and unsupported enamel were left as found and cotton wool rolls were used for isolation. Two drops of NSF or one drop of water were applied to the tooth with a microbrush for two minutes, once in a 12-month period.

OUTCOME MEASURE: At one week, five months and 12 months the presence of active caries, as classified using International Caries Detection and Assessment System (ICDAS II) criteria, was measured. If a blunt probe easily penetrated dentine with light force, active caries was recorded and taken to be a failure.

RESULTS: One hundred and thirty primary teeth in 60 children with a mean age of 6.31 (± 0.60) were randomised. Sixty-three teeth were in the NSF group and 67 in the control group. After one week there were no losses, at the five-month follow up eight teeth were lost from the NSF group due to exfoliation or extraction and five from the control group. At twelve months a further five teeth were lost from the NSF group and 13 from the control group.At the one week follow up there was a 19% failure rate in the NSF group compared to 100% in the control group. At the five month recall this was 27.3% NSF compared to 72.6% water and at the final recall there was a 33.3% NSF failure rate and 65.3% control failure rate. The preventative fraction at this point was 50% and the NNT 3.12. All were statistically significant results (p= <0.05).

CONCLUSIONS: The annual application of NSF solution was more effective in hardening and arresting dentine caries in primary teeth than the placebo. The effectiveness of NSF was found to be similar to silver diamine fluoride when applied once a year, but did not stain the dental tissue black and had no metallic taste. The application is simple, does not require a clinical setting and is inexpensive. NSF was demonstrated to be effective in arresting caries in children in poor communities, but further studies are required to investigate alternative protocols and for use in tooth sensitivity and root caries.