Caries prevention for preschool children using silver diamine fluoride

Abstract

Early childhood caries (ECC) causes pain and infection. The dental infection if left untreated can spread systemically and affect the child's growth and development and general health. This PhD study performed a cross-sectional survey to study untreated ECC and its associated risk factors in Hong Kong. The survey found untreated ECC was prevalent and affected more than half of the 5-year-old children. The untreated ECC prevalence was associated with the district the child lived in. The 5-year-old children on average had 2.8 untreated carious teeth. More than two- thirds of the children with untreated ECC had never visited a dentist. The distribution of untreated ECC was uneven. Children who brushed teeth without toothpaste had more untreated ECC. Children who came from low-income families and with lower maternal education levels had a higher ECC risk. This PhD study also investigated oral health policies, dental services, public health strategies, and epidemiological surveys on ECC in Hong Kong since the 1960s and found that ECC prevalence decreased with improvement in living standards as indicated by the human development index, the provision of 9-year free education, the establishment of a dental school, the provision of water fluoridation, and the implementation of the territory-wide oral health promotion programmes. The results suggested that better education, improved living conditions, and oral health promotion have improved the oral health of preschool children in Hong Kong. However, persistent inequalities and poor oral health remained prevalent among young children despite Hong Kong's economic and educational advancements in the past few decades. Silver diamine fluoride (SDF) is effective in arresting ECC because of its prominent antibacterial and remineralising properties. The World Health Organization (WHO) considered SDF to be effective and safe to meet the most important needs in a health system. The WHO in 2021 included SDF in its Model List of Essential Medicine for both adults and children. We also retrospectively evaluated a dental outreach service by using SDF to arrest ECC among kindergarten children. The service provided SDF therapy to arrest more than 200,000 teeth with ECC from 2010 to 2019 with no report of adverse effects of SDF therapy. Most parents preferred this simple and non-invasive care. The outreach service's success is reflected by the high caries arrest rate and significant reduction in new ECC among kindergarten children. However, unlike the confirmed clinical efficacy of SDF in arresting caries, there has been no clinical trial investigating the caries-preventive effect of SDF in the primary teeth. Therefore, this PhD study performed a 12-month, randomised, double-blind clinical trial to compare the caries-preventive effect of an application of SDF with sodium fluoride varnish to the upper anterior primary teeth of 3- to 4- year-old children. Results indicated that there is no significant difference between SDF and sodium fluoride varnish in preventing new decayed tooth surfaces. More than 70% of the children were rated as totally cooperative with the SDF application in kindergarten. Adverse effects of SDF therapy were neither found at one day nor at about one year after the treatment.