Long-Term Community Water Fluoridation Linked to Lower Adult Tooth Decay: Study
A new study published in the Journal of Dental Research showed that despite being exposed to several alternative fluoride sources, people in the Republic of Ireland between the ages of 34 and 45 who had nearly lifetime exposure to community water fluoridation (CWF) showed lower levels of dental caries than their counterparts in non-fluoridated Northern Ireland.
The cumulative effect of dental caries in their permanent teeth is still problematic, even if rates among youngsters are decreasing. Given its significance in preventing dental cavities, the World Health Organization promotes incorporating community water fluoridation (CWF) into health efforts. The necessity for studies looking at long-term relationships between CWF exposure and dental caries is highlighted by recent reviews. Since Northern Ireland (NI) has not adopted CWF, the Republic of Ireland (ROI), which has fluoridated public water supplies since 1964, offers a natural comparison. In people with near-lifetime exposure to CWF, this study investigates the relationships between CWF exposure and dental caries experience and evaluates whether these relationships vary among tooth surfaces.
Analysis was done on sociological, demographic, and epidemiological data gathered from adults in a prior study. The decaying, missing, and filled teeth (D3CMFT) and tooth surface (D3CMFS) indices were used to measure caries experience. The main study calculated correlations between caries experience and area (as a stand-in for long-term CWF exposure). The incidence rate ratios for explanatory factors, such as CWF exposure, in connection to dental caries experience were evaluated using negative binomial regression models, which are suitable for overdispersed count data.
When compared to those in NI, those in the ROI had noticeably less caries experience. People in the ROI had D3CMFT and D3CMFS scores that were 10.6% and 15.6% lower, respectively, in adjusted analyses. Approximal surfaces showed the biggest difference (18.6%), followed by occlusal surfaces (11.9%) and smooth surfaces (14.9%).
These results corroborate a link between prolonged exposure to CWF and a lower incidence of tooth caries in adulthood. The findings support the continuous assessment of population-level fluoride programs and offer more life-course evidence using clinical measures of illness.
Overall, this study shows that compared to similar adults in unfluoridated Northern Ireland (NI), 34–45-year-olds in the ROI who have had CWF for almost their entire lives had fewer cavities. Consistent exposure to CWF was found to be a dependable predictor of improved oral health across all assessed measures.
Reference:
Cronin, J., Moore, S., Woods, N., Whelton, H., & Harding, M. (2026). Long-term associations between water fluoridation and adult dental caries. Journal of Dental Research, 00220345261442955,. https://doi.org/10.1177/00220345261442955
