Caries control using functionalized tricalcium phosphate fluoride varnish and silver nitrate solution in preschool children

Abstract

Preschool children were still suffering from early childhood caries (ECC) nowadays. A systematic review of ECC situation among 5-year-old children found that the prevalence ranged from 23% to 90% worldwide and most of the studies reported a prevalence rate over 50%. In Hong Kong, 55% of the 5-year-old children had caries experience in 2016. To manage ECC, traditional restorative treatment was often neither available nor affordable. Minimal invasive approach had been advocated. Silver nitrate (AgNO3) solution has been used as an antimicrobial agent for caries treatment. Sodium fluoride (NaF) varnish was found to promote remineralization. To enhance its effectiveness, functionalized tricalcium phosphate (fTCP) has been incorporated into NaF varnish. A recent clinical trial found the use of AgNO3 solution and NaF varnish was effective in arresting ECC. However, there was no published study investigating the effectiveness of the use of AgNO3 solution and NaF varnish with fTCP in arresting ECC. Thus, a randomized, double-blind clinical trial was conducted to compare the effectiveness of 25% AgNO3 solution plus a 5% NaF varnish with fTCP and that of a 25% AgNO3 solution plus a 5% NaF varnish in arresting ECC among preschool children when applied at six-month intervals. Three-year-old children with at least one active dentine carious lesion were randomly allocated into two groups. Children received either the application of a AgNO3 solution followed by a NaF varnish (Group A, positive control) or the application of a AgNO3 solution followed by a NaF varnish with fTCP (Group B, experiment group) once every six month. One examiner performed oral examinations. Visual-tactile assessment was adopted. Lesions with hard surfaces on probing were classified as arrested. The primary outcome was the portion of arrest carious surfaces. Self-administered questionnaires regarding children’s oral health-related behaviours and socioeconomic backgrounds were obtained at baseline and 12-month follow-up. Chi-square test, t test, intention-to-treat analysis and multilevel logistic regression analysis were undertaken. A total of 408 children with 1,831 active carious lesions were recruited at baseline. No significant difference was found between groups regarding children’s background and their oral health-related behaviours and their oral characteristics at baseline and 12-month follow-up. After 12 months, there were 402 children remained in the study (dropout rate: 1.5%). All of them had received treatment twice upon the 12-month oral examination. The 12-month result showed that the application of a AgNO3 solution followed by a NaF varnish with fTCP was more effective in arresting active dentine carious lesion in primary teeth than that of a AgNO3 solution followed by a NaF varnish without fTCP when applied at six-month intervals (46% vs. 39%). Apart from the intervention, the caries-arresting rate was also influenced by tooth surface type, family income and baseline caries experience. The treatment of ECC using AgNO3 solution followed by a NaF varnish with fTCP is painless and easy to be accepted by young children. The treatment is simple, low cost and easy to apply. It can be a useful protocol for management for ECC for young children.