In Vitro Cytotoxicity of Three Dimethacrylate-Based Photopolymer Resins for 3D-Printed Dental Restorations: A Qualitative Morphological Screening on Human Fibroblasts

The rapid adoption of vat photopolymerization (3D printing) in restorative and prosthetic dentistry has outpaced the independent biological characterization of the dimethacrylate resins on which it relies, even though incompletely converted networks can release residual monomers that are cytotoxic to the adjacent oral tissues. This study reports a qualitative in vitro cytotoxicity screening of three commercial photopolymer resins optimized for additive manufacturing: a general-purpose resin (ANYCUBIC) and two resins with a declared dental indication (TEMP PRINT and V-PRINT) performed according to the morphological evaluation described in ISO 10993-5. Aqueous extracts were prepared following ISO 10993-12 and applied to normal human fibroblasts (BJ line, ATCC CRL-2522) at 100% and 50% concentration for 24 h; morphological reactivity was graded on the standardized 0–4 scale by inverted light microscopy against an unexposed control, and supported by a semi-quantitative visual estimate of the proportion of affected cells. All three materials produced a concentration-dependent response. TEMP PRINT retained the best cellular compatibility (grade 1 at 50%, grade 2 at 100%), V-PRINT was intermediate, and ANYCUBIC showed the most pronounced reactivity (approaching grade 3 at 100%), giving an estimated cytotoxicity order of ANYCUBIC > V-PRINT > TEMP PRINT. As a qualitative morphological screening, the findings indicate that the dental-grade resins elicited a milder fibroblast response than the general-purpose photopolymer and support the recommendation that general-purpose resins should not be substituted for certified materials in intraoral use. Confirmation by quantitative viability assays with independent replicates is required before firm conclusions are drawn. In line with the qualitative nature of ISO 10993-5 morphological screening, the reported proportions of morphologically affected cells represent visual scoring rather than direct measurements of cell viability, and the study is therefore presented as an initial biological screening.