Early US projects were at 5 parts per million. In areas of India, fluoride occurs naturally at 14 parts per million and causes widespread physical damage, especially where malnutrition exists. But in the UK, fluoride addition is rigorously monitored to top up naturally occurring fluoride to one part per million. Its benefits over the last 25 years have been very clear.
J E MURRELL
West Wickham, KentReuse content