Results of NHANES evaluation of BPA levels in urine
Recent articles have reviewed research reports on salivary BPA levels and provide a good perspective on the contribution of BPA exposure from dental materials. The findings of studies using current Bis-GMA-based composites and sealants showed that the acute BPA exposure levels associated with sealant placement were a minimum of 50,000–100,000 times lower than the daily recommended exposure limit for adults set by current EPA and NTP guidelines [21, 22]. Thus, exposure levels from dental materials alone are considered to be safe.
So what should be done? As with any biocompatibility issue, the decision to use these materials is a decision of risk to benefit ratio. The oral health benefits from these materials are well established [23–25]. Because the data on BPA levels and safety remains complex, it seems prudent to limit the exposure contribution from dental materials to these most vulnerable populations as much as possible. Some commonsense guidelines have been suggested in dealing with these issues : Limit elective placement of dental sealant and composite resin restorations in pregnant women. When possible, choose materials that are BPA-free. In pregnant women and children, use precautionary application techniques when restorations or sealants are placed to limit BPA exposure. These techniques are aimed at removing the unpolymerized material on the surface and have been shown to return BPA levels to baseline, greatly reducing the acute, short-term BPA exposure associated with sealant placement [27, 28].
Because of the high profile of BPA safety in the press, many patients may express concerns about the use of these dental materials. The ADA recently published some guidelines to help the dental practitioner address these concerns .
BPA and Dental Materials: Addressing Patient Concerns
Here are some key points that can help you answer patient questions about BPA:
According to manufacturers, BPA is not an added ingredient in dental composites or sealants currently on the market.
The main ingredient in most commonly used composites and sealants is Bis-GMA, which has been shown to be stable within the mouth and does not decompose to BPA over time.
Trace amounts of BPA present in raw Bis-GMA are a residue of its manufacturing process.
Some products contain added Bis-DMA as a Bis-GMA viscosity modifier. Bis-DMA is known to decompose to BPA in the presence of salivary esterases (enzymes). However, many current dental resins severely limit or eliminate all Bis-DMA from their formulations.
Although trace levels of BPA can be detected in dental products containing Bis-GMA, the potential exposure level is at least 100,000 times lower than current exposure limits.
BPA exposure from dental materials likely lasts only a few hours after placement of a composite or sealant. Therefore, any BPA exposure is brief and transient.
The preponderance of scientific data over the past 15 years indicates that the amount of BPA exposure from dental restoratives does not present a health hazard.
Compiled from Ref. , used with permission (pending)
5.7 What Can We Do in the Future?
BPA research would benefit from more standardized methodologies to study and report the effects of these compounds in the literature to better facilitate comparisons of the results. In addition, with newer and more sensitive techniques available, studies on longer-term/chronic release of these compounds from dental materials should be possible. Further assessment of volatile release of these compounds during dental procedures should be performed to better delineate potential risks to dental practitioners and staff.
Regulations concerning required product information could be modified to insure that the dental practitioner can make a better informed choice on which materials to use to help limit BPA exposure as much as possible. More extensive studies should be performed on other compounds released from these composite resin systems to assess their estrogenic/toxic effects. Manufacturers should continue to develop new BPA-free materials to offer as options. Of course, these new materials will need biocompatibility testing to insure that new risks are not being introduced.