Fluoride Action Network


Surveys have shown that the prevalence of early childhood caries (ECC) among 5-year-old children decreased from 63% in 1993 to 55% in 2017. Caries experience was unevenly distributed; 81% of the caries lesions were found in 26% of the children. Risk factors, including oral hygiene practice behaviors, sugar consumption, parental oral health-related knowledge, and sociodemographic backgrounds, were significantly related to ECC. Oral health promotion aimed at managing the burden of ECC has been implemented. Water fluoridation was launched in 1961, and the fluoride concentration has been adjusted to 0.5 ppm since 1988. It is considered an important dental public health measure in Hong Kong. The Department of Health set up the Oral Health Education Unit in 1989 to deliver oral health education to further improve the oral health of preschool children. Other nongovernmental organizations also launched short-term oral health promotion programs for preschool children. However, no significant change in the prevalence of ECC has been observed in the recent two decades. There is a necessity to revisit dental public health policies and develop effective evidence-based strategies to encourage changes in oral health-related behaviors to forestall the impending epidemic of ECC in Hong Kong.


Sociodemographic background
There are a number of studies showing that socioeconomic factors are related to children’s dental caries experience.16,17,19,21 From 1993 to 2017, all oral health surveys concluded that household income was significantly associated with preschool children’s dental caries experience. Children from families with higher income and whose parents had a higher education level had lower dental caries prevalence.
These results indicated that social inequality exists among the dental health of preschool children in Hong Kong. Underprivileged children may have a higher risk of developing caries lesions. Besides, the demographic characteristics also affect the dental caries experience. As Hong Kong was colonized by the British Empire, its culture, foods, and living lifestyles are slightly different from Mainland China. The epidemiological survey conducted in 2009 reported that children who were born in Mainland China had significantly higher dental caries experience than those born in Hong Kong.16

Water fluoridation
…  In Hong Kong, the water fluoridation program was introduced in 1960 with a fluoride level of 0.8 parts per million (ppm). After that, the mean dmft score of the 12-year-old children decreased dramatically from 4.4 in 1960 to 1.5 in 1968.15,30 Subsequently, the concentration of fluoride increased to 1.0 ppm in 1976.31 However, the results of this survey indicated that the prevalence of dental fluorosis among 7- to 12-year-old children also increased to 64%.30 Therefore, the concentration was adjusted to be 0.7 ppm in 1986. Later, the epidemiological survey in 1988 reported that the dental
fluorosis remained prevalent (47%). Then, the concentration of fluoride was reduced to 0.5 ppm in 1988.32 Until now, the fluoride level has remained at 0.5 ppm in Hong Kong. Optimal fluoride concentration in drinking water was determined by various factors including environmental temperature, daily water consumption, and access to different sources of fluoride.33 The amount of fluoride ingested during the summer time was higher than that during the winter time.34 For people living in tropical or subtropical regions like in Hong Kong, they tend to consume more water than those living in cooler regions.34 Besides, young children may be at risk of ingesting fluoride from toothpaste which is commercially available and affordable for most of the families. Therefore, the fluoride concentration in Hong Kong has been adjusted to be 0.5 ppm, which is lower than that in the cooler areas such as in the US (0.7 ppm).35 Although water fluoridation is one of the most significant dental public health projects benefitting all residents in Hong Kong, the caries statuses of preschool children were unsatisfactory. Additional effective evidence-based oral health programs for preschool children
are needed.