Parents looking for BPA Free Sealants for their children are assured by the dental manufacturers that their sealants are “BPA free”. It turns out the statement “BPA free sealants” needs to be carefully evaluated. This whole episode reminds me of Sigg, the Swiss aluminum water bottle manufacturers that everyone switched to, to stop buying plastic water bottles, who were forced to admit their plastic lined bottles did in fact contain BPA.
Dental sealants are plastic. They are made from monomers that are derived from BPA, for example bis-GMA and bis-DMA. BPA by itself is rarely used in dental sealants. So when dentists and the dental manufacturers say they have BPA free sealants, they are correct – until they begin to worn down by the saliva and mastication in a chemical reaction that creates BPA.
The crucial distinction to make it the type of monomer used. There are two types commonly used in the industry – bis-GMA and bis-DMA. A team at Heidelberg University performed the analysis and published their results in the Clinical Oral Investigations Journal.
“For Bis-GMA-monomer, no BPA could be detected under any hydrolytic conditions chosen (detection limit: ≤1%). For Bis-DMA-monomer an increase of BPA was observed at pH 11, resulting in a conversion of approx. 100% Bis-DMA to BPA. When Bis-DMA was subjected to esterase, a conversion of 82.5 % resulted after 24 h; saliva led to an 81.4 % conversion of Bis-DMA after 24 h. Hence, we conclude that the results reported in the literature may be attributed to the Bis-DMA-content of the fissure sealant tested (Delton). No BPA-release is expected under physiologic conditions from fissure sealants based on Bis-GMA if pure base monomers are used.
While the original sealants do not contain BPA, Bis-DMA is hydrolyzed to BPA by the saliva which will result in BPA being released from the sealants as they degrade over time. It seems as if bisGMA based sealants are much more stable over time than Bis-DMA based structures. Make sure you select one of the bisGMA resins.
The Americal Dental Association ADA in it’s research on sealants says; ” As a product of the degradation of the material in the oral cavity: Composite resins are formulated from a mixture of monomers that are commonly based on bisphenol A glycidyl methacrylate (bis-GMA). Some composite resins may contain other monomers, in addition to bis-GMA, that are added to modify the properties of the resin. An example is bisphenol A dimethacrylate (bis-DMA). Bis-DMA-containing materials can release very small quantities of BPA because bis-DMA is subject to degradation by salivary enzymes.”
So it’s not to enough to specify “BPA free Sealants,” when you want a BPA free sealant. You need to ask for a BPA free sealant that does not release BPA in the mouth over time. There are plenty of bis-GMA sealants out there. Avoid the ones made from bis-DMA.
At the end of the day, do you want to put plastic in your mouth at all? The benefits of dental sealants for children are very good. Although you can do wonders with diet to remineralize the teeth and make them strong, it’s not always the easiest feeding kids on a soda free, sugar free diet rich in cod liver oil and vegetables. So even with the dangers of plastic in the mouth, it is still worth putting sealants in.