Water fluoridation for the prevention of dental caries.
Level 3 - non-randomized controlled study
Systematic review of non-randomized prospective controlled studies
PubMed 39362658 · doi:10.1002/14651858.CD010856.pub3
What was done
This Cochrane systematic review evaluated prospective controlled studies examining the initiation or cessation of community water fluoridation (CWF) on dental caries and its association with dental fluorosis. Databases including CENTRAL, MEDLINE, and Embase were searched through August 2023. Outcomes included changes in decayed, missing, or filled teeth and surfaces (dmft/DMFT, dmfs/DMFS) and the proportion of caries-free children, stratified by data collection before or after the widespread introduction of fluoride toothpaste in 1975.
What was found
Across 157 included non-randomized studies, contemporary post-1975 evidence for CWF initiation showed: - Primary dentition dmft: Mean difference (MD) of 0.24 teeth in favour of CWF (95% CI -0.03 to 0.52; P = 0.09; 2 studies, 2,908 children; low-certainty evidence). - Caries-free proportion: MD -0.04 in primary dentition (4 percentage points higher; 95% CI -0.09 to 0.01; P = 0.12; 2 studies, 2,908 children) and MD -0.03 in permanent dentition (3 percentage points higher; 95% CI -0.07 to 0.01; P = 0.14; 2 studies, 2,348 children). - Pre-1975 evidence, contemporary permanent DMFT/DMFS changes, and CWF cessation (1 study, 2,994 children) were all rated very low-certainty. - Fluorosis: At 0.7 ppm fluoride, approximately 12% of participants had fluorosis of aesthetic concern (95% CI 8% to 17%; 40 studies, 59,630 participants) and 40% had any fluorosis (95% CI 35% to 44%; 90 studies, 180,530 participants; low-certainty).
Why it matters
In modern populations where fluoride toothpaste is widely used, the incremental caries-preventive benefit of community water fluoridation is smaller and less statistically certain than indicated by historical pre-1975 studies.
Limits
All 157 included studies were non-randomized, introducing high risks of residual confounding and unblinded outcome assessment. Contemporary caries-prevention estimates relied on very few studies (2 to 4 studies per outcome) with confidence intervals spanning both benefit and no benefit. Only one post-1975 study evaluated socioeconomic disparities, and non-fluorosis adverse event data were sparse and of very low certainty.
Cited by
- contradicts Childhood cavity rates in Europe are about the same as in the United States despite Europe lacking water fluoridation.