Study Warns Resins In Some Clear Tooth Aligners May Leach Toxins

Two 3D-printable resins used in some dental applications have been found to leach toxins that may harm reproductive health, according to a new study from Northwestern University. The discovery, which is described as 'unexpected,' was made when researchers were validating various commercial resins for 3D printing materials that would have been used to culture reproductive cells.

The study focuses on resins called Dental SG and Dental LT, both of which are used in clear tooth aligners, among other things. The materials are marketed as biocompatible for use in dental devices like these, but were found to 'readily leach compounds into their surroundings,' according to the researchers.

The leached compounds are capable of inducing 'severe toxicity' to the immature precursor to eggs called the oocyte — this finding was based on mouse oocytes during an in vitro study. The discovery indicates that dental applications involving these 3D-printed resins may have a negative impact on reproductive health, though in vivo research is needed to further explore the potential consequences.

One of the co-corresponding authors of the study, Francesca Duncan, said:

Our results are important because they demonstrate leachates from commonly used materials in 3D printing [are] slated as 'biocompatible' but may have adverse effects on reproductive health. There is a critical need to better understand the identity and biological impact of compounds that leach from these materials.

The study notes that DLT resins in particular are used to make dental retainers, which are often kept in the mouth for long periods of time. This extended exposure may be particularly harmful, but in vivo effects are yet to be determined.