A new Australian study confirms that lifetime access to community water fluoridation (CWF) is associated with reduced tooth decay for adults – at least in the age groups 15 – 34 years and 35 – 44 years.
The study is reported in the paper: Do et al., (2017). Effectiveness of water fluoridation in the prevention of dental caries across adult age groups. Community Dentistry and Oral Epidemiology.
Other workers reported similar results. But Do et al., (2017) had a closer look at the data, because of the difficulties in assessing both access to CWF, and tooth decay, in adults. In particular, they carried out a secondary analysis which looked at lifetime access to CWF and tooth decay within defined age groups as well as across age groups of adults aged between 15 – 91 years.
They found the association of access to CWF with reduced tooth decay was strongest for the youngest adult age group, 15 – 34-year-olds. The association was weaker, but still significant, for the 35 – 44 years age group. However, they did not see a significant association for the remaining age groups, 45 – 54 years and 55+ years.
The authors discuss possible reasons for what they call the “fading” of apparent benefits from CWF with age.
1: Lack of exposure to CWF during childhood for the older age groups. This is because CWF was not present when they were young. The authors say:
“there is some evidence among children at least of the importance of a critical period of exposure, where either the incorporation of fluoride into the developing tooth may be crucial or the establishment of a positive mouth ecology may set a child on a lifelong trajectory.”
This would be in line with research showing a systemic effect of fluoride for developing teeth in children. There is also that those older adults were exposed to risks of tooth decay before later being exposed to CWF.
2: A limit to the measurement of tooth decay in adults because the measures of tooth decay:
“increasingly shows saturation of all susceptible surfaces, whereby more members of an age group approach a ceiling in the sum of the surfaces with past or present caries experience. . . . It should be emphasized that, for the older age groups, this saturation might have occurred before access to FW had become available in Australia.”
So, yet another confirmation of the benefits of CWF for adults as well as children.