BPA resin

Worried about BPA resin in your dental work?

Are you concerned about BPA resin in dentistry?  The number of chemicals in a composite filling is pretty large and many are known to be toxic to some degree.

What does BPA resin do in humans?

Let’s talk about what BPA resin does in the human body, first.  BPA resin is an endocrine disruptor and binds to the human estrogen receptor.  Depedning on the research BPA either binds at 1000-5000 times weaker levels Roy 2009 Med Sci. or is similar to estradiol Vandenberg 2007 Reprod Tox.  It also binds to glucocorticoid, androgen, and throid recptors.  Sharma 2016 JADA 18-20.

What is BPA resin?

BPA is bisphenol A, a synthetic compound that is mass produced globally.  It is unavoidable and you are exposed to it, no matter what.  Check the graph at the bottom to see what I mean.  US Environmental Protection Agency set the safe level at 50 µg/kg/day.  BPA is used directly in the manufacturing of some resins (especially bis-GMA).  BPA derivatives such as bisphenol A-glycidyl methacrylate (bis-GMA), bisphenol A-dimethacrylate, and bisphenol A-ethoxylated dimethacrylate are all used in dental resins that polymerize via chemical or light activation.  Fleisch 2010 Pediatrics  BPA is a byproduct of chemical degradation of these resin-based dental materials, which is what causes even BPA free materials to release BPA.  It is also found in nearly all composites from incomplete chemical reactions on the manufacturing side. (referenceSharma 2016 JADA article’s references 5-10 support previous statements.

BPA resin research

Composites also have been proven to result in higher levels of BPA in the urine, but only for a short time Maserejian JADA 2016.  How the composite is placed makes no difference,  a protective rubber dam has no influence on amount of BPA leaked into your system.  BPA in the urine does mean the body is eliminating it, but how much of it?  reference  A systemic review in JADA 2014 showed that no BPA was ever detected in the blood and it appears that the very minor amounts that are present in saliva and get into our system are being quickly and effectively eliminated into the urine.  The fact that BPA was at no point detectable in the blood makes me wonder if the detection levels are set too high.  BPA is an endocrine disruptor and very small doses may have an impact.

There are several studies showing effects like prenatal exposure to BPA being tied to hyperactivity and anxiety, especially in girls.  Newer studies are showing effects on behavior. Maserejian 2012

Good lit review

bpa resin

BPA resin free mouth.

What can you do to mitigate BPA resin in dentistry?

People looking for BPA free dentistry simply need to ask for their dental work to be “indirect” gold or porcelain.  This will increase your costs by 3-6x but that is a choice you are free to make.  Most dentists would much rather give you a gold or porcelain filling anyway, because they do hold up very well.  The main reason dentists do not is that so few people are willing to pay the extra cost.

Another option that is newer to the market is the class of composites called ormocer.  The chemistry of this class is better as there is no BPA resin and ormocers are more highly cured.  They are new and patented so despite being better chemistry, will take a awhile to become main stream.  I use these occasionally but the esthetics aren’t there yet for anterior teeth and the consistency is stiffer than I prefer.

Is BPA resin an issue in dentistry?

Almost certainly not.  Even if the ADA is way off with their number of .09ng daily exposure from 4 dental sealants that is almost nothing compared to the 6020ng daily exposure the European Food Safety Authority says we get.  The following is a breakdown of the BPA sources we receive based on EFSA numbers.  Although it discusses sealants and not fillings, sealants often contain more BPA than fillings so comparing just those is reasonable.

BPA resin daily exposure


I cover the BPA resin topic to some extent in my amalgam vs composite blog post.
Bryan Bauer, DDS, FAGD

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