Sir, in the recent letter Bisphenol alert (BDJ 2008; 205: 583), the sentence 'The overall conclusion is that there is little to worry about...' appeared. This contrasts with findings of other workers in the field. The topic of human exposure to compounds which have potential oestrogenic influence has aroused interest from different branches of medicine. Adult or mature mammalian subjects have been used in experimental models in the past. However, findings change and questions are raised when the immature or growing mammalian subject is used within the experimental model. Work is now being directed towards specific time frames in which compounds may exert irreversible influence on developmental pathways on the growing embryo. Work done by Vom Saal, and others, has contributed to this debate. He found 2 ng/g body weight (2 ppb) of bisphenol A, fed to mice between 11 to 17 days gestation, produced a permanent change in the developmental pathways of specific organs.1 This work has been independently verified by others.

It is recognised that the contents of resin based restorative materials used in dental practice cannot be solely responsible for the total body burden a patient may be exposed to. However, the likelihood exists that they may contribute towards overall exposure of the patient. In order for the dental community to contribute meaningfully to wider scientific discussion in this area, further research would be welcome.