News Europe
PARIS, France: New research from France has suggested that bisphenol A (BPA), a chemical widely used in plastics and dental resins, is a potential causative agent of molar incisor hypomineralisation (MIH). Damage similar to this mineralisation disorder, which occurs selectively in permanent incisors and first molars, was observed in rodent teeth after treatment with BPA.
Researchers from the National Institute of Health and Medical Research treated the incisors of rats daily with low doses of BPA (5 µg/kg/day) from birth to 30 or 100 days. At day 30 already, the erupting tooth enamel exhibited signs of hypomineralisation similar to human MIH. The researchers suggested that BPA disrupts normal protein removal from the enamel matrix and leads to mineral depletion, making the teeth more fragile.
However, no such effect was observed in 100-day-old rats. As their erupting incisor enamel was normal, the scientists suggested that enamel formation is only sensitive to MIH-causing agents during a specific time window in early development.
As it is strongly suspected that BPA has the same effects on humans as on laboratory animals, it could be a causal agent of MIH, concluded Dr Sylvie Babajko, a research director at the institute.
The condition is found in roughly 18 per cent of children aged between 6 and 8. The permanent maxillary central incisors and first molars are affected most often, and the permanent mandibular incisors less frequently. Usually, the teeth show a yellowish-white to brown discoloration, which may affect only certain areas of the tooth or the whole tooth. The teeth of MIH children are commonly hypersensitive to pain and more susceptible to cavities.
Endocrine-disrupting chemicals, including BPA, are ubiquitous environmental pollutants and increasingly associated with health concerns. Prior studies have associated it with adverse effects on reproduction, neurological development and metabolism. The manufacture and marketing of babies’ bottles containing BPA were banned in Europe in 2011. The prohibition will be extended to all food containers in France from July 2015.
The study, titled “Enamel defects reflect perinatal exposure to bisphenol A”, was published online on 10 June in the American Journal of Pathology ahead of print.