Residual monomers and volatile leachable substances of conventional and CAD/CAM-fabricated denture base materials -...

Methacrylic acid ester-based resins for denture fabrication release residual monomers and leachable substances that may interact with oral tissues. With increasing adoption of CAD/CAM technologies, a systematic comparison of leachable substance profiles and surface characteristics across polymerization methods is needed.

This study compared the chemical composition and profiles of leachable substances of four denture materials - autopolymerized, thermal polymerized, milled, and 3D-printed - using gas chromatography-mass spectrometry (GC-MS). Surface roughness was evaluated by confocal microscopy.

GC-MS screening detected 24 distinct compounds in the solid specimens. Among the MMA/PMMA-based materials, methyl methacrylate content was highest in the thermally polymerized resin, followed by the autopolymerized and milled materials, and absent from the 3D-printed resin, consistent with its MMA-free formulation. MMA levels in the extracts did not exceed those of the negative control in any group. Surface roughness was comparable on the polished face (R_a ≈ 0.21-0.25 μm), consistent with SEM findings but material-dependent on the unpolished, tissue-contacting face (R_a 0.37-1.03 μm).

Both fabrication method and material formulation influence the volatile and semi-volatile extractables of denture resins. As the present GC-MS screening may not reliably capture high-molecular-weight dimethacrylates such as Bis-EMA and UDMA, novel CAD/CAM materials require additional, complementary toxicological evaluation.

The leachable substance profiles of CAD/CAM denture resins, particularly the distinct compounds detected in the 3D-printed material, underscore the need for material-specific biocompatibility data to support informed clinical material selection and patient safety.