Sir, we write regarding the letter by Bland and Bland1 and seek to reassure the authors and readers regarding fluoridation and dental fluorosis.

The World Health Organisation's recommendation2 of a maximum fluoride concentration in drinking water of 1.5 mg/L is designed to be protective against any adverse effect, including dental fluorosis which might be unsightly. The target level for fluoridation in England is 1.0 mg/L and in some parts of the UK, developing teeth are exposed to fluoride in water occurring naturally at similar levels.

The most recent study of fluorosis in England (2016)3 compared children in fluoridated Newcastle and Birmingham with non-fluoridated Liverpool and Manchester. A higher prevalence of any dental fluorosis was observed among children in the two fluoridated cities (61% vs 37%) and of fluorosis above the threshold generally considered to be aesthetically objectionable (10% vs 2%). There was, however, no significant difference in the degree of aesthetic concern held by the children themselves in the fluoridated and non-fluoridated cities.

Bland and Bland suggest that successive generations of children may find fluorosis more objectionable. This may be true, but research to date suggests a complex picture of mild fluorosis possibly making teeth more attractive4 and fluorosis possibly diminishing with age.5

Swallowing excess fluoride toothpaste during tooth development is also a potential risk for dental fluorosis and recent guidance has re-stated the importance of avoiding excess ingestion.6

We agree that ongoing professional education is important regarding counselling and managing patients presenting with dental mottling. Where mottling is severe enough to have an aesthetic impact, differential diagnosis should include the possibility of alternative diagnoses such as systemic disease or amelogenesis imperfecta and a specialist opinion considered.

With many years of collective experience working in fluoridated and non-fluoridated areas, fluorosis has not been a general cause of concern for our communities but the impact of caries on individuals and services remains a significant burden, especially for non-fluoridated communities. Water fluoridation is an effective and safe public health measure.