Caries preventive effect of fluoride in milk, salt and tablets: a literature review

There are a number of studies in the literature about the effectiveness of fluoride in tablets, fluoride added to frequently-consumed food like milk, or to food additives like salt, in prevention of dental caries. This literature has been evaluated in different evidence based reviews.

The scope of this paper was to identify the most recent evidence-based reviews on the effect in caries prevention from added fluoride in milk, salt and fluoride tablets/drops including newer RCT studies, and to synthesize the findings into practice guidelines. The key question was as follows: Does regular use of fluoride in milk, salt and fluoride tablets/ drops prevent dental caries among children and adolescents?

MEDLINE, EMBASE and EBM reviews (Cochrane database of systematic reviews) were searched using modified filters from a Cochrane review. One evidence-based report on fluoridated milk was identified. Salt fluoridation was covered by three HTA reviews. One Cochrane protocol on the caries preventive effect of fluoridated salt was identified.

Very few studies of good quality were identified in general. Two studies on fluoridated milk were tabulated and seven studies dealing with fluoride tablets/ drops were analysed. One study showed a 78% reduction in caries in newly erupted permanent teeth among 8 year olds after 3 years with fluoridated milk. For primary teeth one study showed 31% caries reduction. The differences between fluoride-group and control were statistically significant. The reduction in caries prevalence in the fluoride tablet group compared with a negative control varied from 81% (carious surfaces in permanent teeth erupted in the study period) to 49% in DMFS for all permanent teeth. No RCT studies on fluoridated salt were identified.

There is limited evidence that F tablets and drops are effective, and compliance is a key factor. There are good reasons to believe that fluoride in different applications and formulas does work as caries preventive agents under supervision. There is a need for new, well-designed studies within this field, but the use of negative controls without any fluoride exposure is difficult due to ethical reasons. In particular new research is needed concerning possible caries preventive effect of fluoridated milk and salt.