On the safety of dental fillings

For many years there have been questions raised regarding the safety of dental amalgam (silver) fillings. The concerns over silver fillings stem from the fact that they contain mercury. While mercury in its free elemental form is toxic to humans, the relevant question is whether or not mercury that is bound to other metals in a silver filling poses any risk.

Although there are groups who are passionately advocating governments to ban the use of dental amalgam, the largest body of peer-reviewed scientific evidence suggests that there is no significant risk, and no need for such a ban. Regulatory bodies, government agencies and member organizations in Canada (including Health Canada and the Canadian Dental Association) have continued to endorse dental amalgam as a safe option for restoring decayed teeth.

More recently, similar questions have been raised regarding the safety of composite resin (white) fillings. Concerns over white fillings are based on the fact that they contain the chemical bisphenol A. BPA is known to interfere with the endocrine system in humans, and may be linked to behavioural disorders, particularly in developing children.

To be fair, most of the concern about BPA is over its use in food packaging, re-sealable food storage containers and plastic drinking bottles. Studies have shown that when plastic products containing BPA are heated, BPA is released from the plastic. It is primarily for this reason that Health Canada has placed restrictions on plastic infant feeding bottles, and they have disappeared from the market in favour of glass bottles.

Regarding BPA in dental fillings, the relevant question is analogous to the one asked about silver fillings, and that question is how much BPA is actually released from white fillings. Studies have shown that release of BPA from white fillings is exceptionally low, and insignificant in comparison to environmental exposure to BPA. The scientific community continues to support white composite fillings as safe, and Health Canada and the Canadian Dental Association also continue to endorse the use of white fillings.

The bottom-line question, of course, is what is the best material to repair damaged or decayed teeth? Dentists are asked this question all the time, and unfortunately there is no single universal material that is best in all situations. The problem we face is that we have not yet come up with a ‘natural’ material to replace missing tooth enamel, and everything we use in restorative dentistry is synthetic. Even gold, arguably the best of all restorative materials (albeit extremely expensive and not so pretty to look at in a smile!), has to be bonded to teeth with an adhesive cement, which is of course synthetic and usually contains BPA.

For the present, the best strategy continues to be prevention. Maybe that is why dentists continue to nag their patients to floss!

 

Dr. Allan Katchky is a dentist who practises in the East End  ~  416-694-2220

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