3D printable resins used in dental applications are usually marketed as biocompatible for use in dentistry. This is the reason for the increase in the use of these resins lately. They are mostly used in medical devices and tissue-engineered constructs.

However, a recent study by Northwestern University has found that they readily leach compounds into their surroundings. These compounds can induce severe toxicity in the oocyte, the immature precursors of the egg while eventually have to be fertilized.

The whole study was carried out in mouse oocytes. The research team made this unexpected discovery while validating the use of commercially available resins to 3D print materials to culture reproductive cells.

"Our results are important because they demonstrate leachates from commonly used materials in 3D printing slated as 'biocompatible' but may have adverse effects on reproductive health," said Francesca Duncan, co-corresponding author of the study and assistant professor of obstetrics and gynecology at Northwestern University Feinberg School of Medicine. "There is a critical need to better understand the identity and biological impact of compounds that leach from these materials." The final study was published in the journal Chemosphere on January 26.

While there have been a few previous studies investigating potential toxicities due to exposure to 3D-printed materials, there have been no studies investigating the potential reproductive toxicities induced by these materials in mammalian models.

The research team discovered the toxicity while using 3D-printing technology to create the first ex vivo model of the female reproductive tract. They characterized the leachates of DLT resins using mass spectroscopy and identified Tinuvin 292 (BASF), a commercial light stabilizer that is commonly used in the production of plastic materials, as a major component. The researchers attributed the significant ovo-toxicity to this substance.

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"Despite the revelations surrounding BPA almost 20 years ago, it is still rare that the potential impact new materials may have on reproductive health is rigorously and systematically studied despite their ubiquitous nature in our day-to-day lives," Duncan said.

While the results of the study only provide evidence for egg toxicity of these materials in an in vitro setting, whether there are possible in vivo effects needs to be further examined, scientists said. This is especially the case for DLT resins, which are intended for making oral retainers that must stay in one's mouth for long periods of time, leading to extended exposure in the body.

In terms of the next steps, scientists plan to investigate whether in vivo exposures to Dental SG and Dental LT resins have egg toxicity similar to what occurs in vitro, examine whether there are sex differences in reproductive toxicity in response to DSG and DLT , and examine the human exposure levels to Tinuvin 292.

Source: The study, titled “Dental resins used in 3D printing technologies release ovo-toxic leachates,” was published in Volume 270 of Chemosphere.