A new study finds that many modern additively manufactured dental materials are nearly invisible on common radiologic scans, raising safety concerns for dental laboratories and clinicians using 3D-printed guides and templates.
Researchers tested 15 materials commonly used in computer-aided manufacturing by scanning standardized scan bodies and small splinters placed in porcine muscle and subcutaneous tissue. They compared cone-beam CT (CBCT) visual detectability with computed tomography (CT) measurements in Hounsfield units (HU).
CT density measurements showed that the 3D-printed materials clustered between roughly 69 ± 5 HU and 130 ± 5 HU—values very similar to muscle tissue. On CBCT, neither the larger cylinders nor the smaller fragments were reliably visible in muscle or fat; the smallest splinters were the hardest to tell apart from surrounding tissue.
By contrast, conventional dental materials used for temporary restorations and silicones were far more radiopaque: Futar D® measured about 1,031 ± 13 HU and Luxatemp® about 3,244 ± 69 HU, making them significantly easier to detect on imaging.
The authors conclude that, at present, CT and CBCT are often inadequate for visualizing modern 3D-printed dental materials embedded in soft tissue. That shortfall could complicate retrieval of broken guide fragments and increase the risk of retained foreign bodies, ingestion or aspiration during procedures.
The study recommends that manufacturers and dental laboratories consider adding radiopaque markers or modifying material formulations so fragments are radiographically distinguishable.
Clinicians should also be aware of the detection limits, inspect guides carefully before and during use, and follow strict protocols for locating and retrieving fragments if breakage occurs. Further research is needed to develop practical solutions and to confirm findings across additional materials and clinical scenarios.
