Release of Bisphenol A from dental materials: risks and future perspective

This summary was written by Dr Anu Polster on behalf of the Dental Instruments, Materials & Equipment (DIME) committee on the following scholarly article: Tichy A, Srolerova T Schwendicke F. Journal of Dental Research 2025;104(10): 1051-1060. doi: 10.1177/ 00220345251337728

The ongoing phase-out of dental amalgam has led to a rise in the use of resin-based dental materials. While resin-based composites, adhesives and sealants provide significant improvements in aesthetics and acceptable mechanical strength, concerns remain about their biocompatibility – particularly the potential release of bisphenol A (BPA).

BPA is a synthetic chemical used widely in plastics and epoxy resins and has long been recognised as an endocrine-disrupting chemical. It can interfere with hormonal pathways and is characterised by a non-monotonic dose–response relationship, where very low exposures may have significant biological effects.

Although dietary sources remain the primary source of BPA exposure, resin monomers derived from BPA may degrade to release trace quantities into the oral environment.

In 2023, the European Food Safety Authority (EFSA) proposed reducing the tolerable daily intake of BPA by 20,000-fold to 0.2 ng/kg body weight, based on immune-system effects observed at extremely low exposure levels. EFSA’s stance has major implications for dentistry.

The main aims of this review were to:

1. summarise the controversy surrounding BPA, its associated health risks, and regulatory shifts.

2. critically evaluate the current evidence on BPA release from dental materials.

3. explore mitigation strategies and outline future research directions to guide the development of safer and more biocompatible dental materials.

Key findings

Animal and in vitro studies link BPA to adverse effects on the reproductive, neurological, metabolic and immune systems. BPA’s non-monotonic dose–response relationship means very low exposures may have significant biological consequences. Even trace exposures to BPA may be harmful, particularly to vulnerable groups such as infants, children and pregnant women.

While daily exposures up to 50μg/kg body weight were previously considered safe by US authorities, EFSA’s 2023 reassessment reduced the tolerable daily intake to just 0.2μg/kg body weight. This means that sources previously regarded as negligible – including resin-based dental restorations – now merit closer scrutiny.

The review highlights that resin-based dental materials rarely contain BPA itself. Instead, they contain derivatives such as BisGMA, BisEMA, BisDMA and polycarbonate compounds. Their potential to release BPA depends largely on chemical structure:

• BisGMA and BisEMA contain ether linkages, which are resistant to hydrolysis, making BPA release unlikely. Most studies confirm only trace or undetectable levels far below environmental background exposure.

• BisDMA and some polycarbonate derivatives contain ester linkages, which are susceptible to hydrolysis. In these cases, transient salivary BPA elevations have been observed immediately after sealant placement, particularly in paediatric population. These elevations typically subside within hours to days.

Despite these patterns, the authors note that inconsistent study methodologies make it difficult to draw firm conclusions. Variability occurs in specimen preparation (curing, finishing and polishing resin-based dental materials), the choice of extraction media (water, ethanol or saliva substitutes), the duration of testing and the analytical methods used as above. Reporting formats also vary
(by concentration, per surface area or per restoration) making direct comparisons difficult and hindering meaningful analysis.

In vivo biomonitoring and animal studies suggest that BPA from dental sources does not accumulate in tissues and is rapidly metabolised an excreted. However, there is a lack of long-term human data, particularly regarding repeated and extensive dental treatments. Overall, resin-based dental materials appear to contribute only a fraction of the total BPA exposure, often less than 0.1% of daily intake. However, under EFSA’s newly defined safety threshold, even this small contribution could exceed acceptable limits.

Tichy and colleagues outline several approaches to reduce BPA exposure in dental practice:

Material innovation and selection

• Encourage the development of BPA-free alternatives and priorities formulations based on monomers not prone to BPA hydrolysis.

• Promote transparency from manufacturers regarding monomer composition and potential for release.

Clinical practice modifications

• Apply optimal curing protocols to maximise polymerisation and reduce residual monomers.

• Polish and rinse restorations after placement to minimise surface release.

• Consider patient factors; in children who may receive multiple sealants, cautious material selection is important.

Research priorities

• Establish standardised testing protocols to address variability in laboratory studies.

• Conduct realistic in vivo research incorporating saliva, mastication and oral temperature fluctuations.

• Expand biomonitoring studies in patient with significant resin-based restorations.

• Investigate toxicokinetics, including absorption, metabolism and elimination pathways of dental BPA.

• Align with global regulatory framework while ensuring that public concern does not overshadow the clinical benefits of resin-based dental materials.

This review by Tichy, Srolerova and Schwendicke places the issue of BPA release from dental materials within the broader debate on chemical safety, regulation and patient trust. While current evidence suggests that resin-based dental materials are a relatively minor source of BPA exposure, the regulatory change led by EFSA implies that even minimal released cannot be dismissed. Looking ahead, the authors stress the importance of interdisciplinary collaboration. Researchers, clinicians, material scientists, manufacturers and regulators must work together to:

• refine methodologies for BPA detection and reporting;

• develop next generation restorative materials that balance mechanical performance, aesthetics and biocompatibility; and

• reassure patients and the public by providing clear evidence -based communication about risks.