{
  "abstract": "Per-layer UV exposure during 3D printing may influence polymerization and the biological response of photocurable aligner resins. This study evaluated exposure-dependent cytotoxicity of Tera Harz TC-85 and NextDent Ortho Flex and performed an exploratory screening of selected resin-specific printing conditions for ER-selective estrogen-like responses. TC-85 was printed at 2.0, 2.4, 3.0, and 4.0 s per layer, and Ortho Flex at 5.0, 6.0, 7.0, and 8.0 s per layer. The resin-specific per-layer UV exposure ranges were selected based on our previous physicochemical characterization of the same materials and printing system. Extracts were prepared according to ISO 10993-12. Cytotoxicity was assessed in human gingival fibroblasts using the MTT assay, while selected conditions (TC-85, 2.4 s; Ortho Flex, 7.0 s) were evaluated in estrogen receptor (ER)-positive MCF-7 and ER-negative MDA-MB-231 cells as an exploratory screening assay rather than a direct test of ER activation. For both resins, per-layer exposure condition, extract concentration, and their interaction significantly affected the normalized MTT response. At 50% extract concentration, normalized MTT responses ranged from 89.2% to 111.3%, whereas Ortho Flex ranged from 8.8% to 76.8%, with the 8.0 s condition being the only Ortho Flex condition above the 70% cytotoxicity threshold. Ortho Flex showed pronounced cytotoxicity in concentrated extracts, particularly at shorter exposure times, whereas TC-85 showed a less monotonic exposure-dependent pattern. In the exploratory screening, the 6.25% Ortho Flex extract produced a normalized MCF-7 MTT response of 129.1%, but this was comparable with the corresponding saline vehicle response of 137.0% and was not statistically greater than the response in ER-negative MDA-MB-231 cells. No statistically supported ER-selective response was detected for either tested resin under the specific screening conditions; however, exposure-time dependence of this response was not evaluated. Per-layer UV exposure therefore influenced the HGF-1 MTT response in a resin- and concentration-dependent manner. For dental laboratory practice, these findings support the use of resin-specific, validated printing parameters rather than transferring exposure settings between materials; deviations from manufacturer-specified processing conditions should be independently validated before clinical use.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Orthodontics, School of Dental Medicine, University of Zagreb, 10000 Zagreb, Croatia",
    "Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, 10000 Zagreb, Croatia"
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 3,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Luka Šimunović",
      "orcid": "0000-0003-2848-6041"
    },
    {
      "affs": [
        1
      ],
      "name": "Antun Jakob Marić",
      "orcid": "0009-0008-2099-3237"
    },
    {
      "affs": [
        0
      ],
      "name": "Senka Meštrović",
      "orcid": "0000-0003-3224-3579"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/0dh67q3xe6tpa.bib",
  "cited_by": 0,
  "doi": "10.3390/polym18202469",
  "fulltext_url": "https://europepmc.org/articles/PMC13709321",
  "id": "0dh67q3xe6tpa",
  "issns": [
    "2073-4360"
  ],
  "landing_url": "https://www.mdpi.com/2073-4360/18/20/2469",
  "language": "eng",
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "3505|Dental materials and restorations"
    ]
  ],
  "openalex": "W7221309912",
  "pdf_url": "https://europepmc.org/articles/PMC13709321?pdf=render",
  "pmcid": "PMC13709321",
  "pmid": "42942590",
  "published": "2026-10-10",
  "publisher": "MDPI AG",
  "ris": "https://research.draconitic.com/paper/0dh67q3xe6tpa.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:44Z",
      "native_id": "10.3390/polym18202469",
      "source": "crossref",
      "url": "https://www.mdpi.com/2073-4360/18/20/2469"
    },
    {
      "first_seen": "2026-10-30T12:22:24Z",
      "native_id": "MED:42942590",
      "source": "europepmc",
      "url": "https://europepmc.org/article/MED/42942590"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "issn:2073-4360",
      "subfield": "materials-polymers"
    }
  ],
  "title": "Per-Layer UV Exposure-Dependent Cytotoxicity of 3D-Printed Aligner Resins and Estrogen-like Activity Screening",
  "title_text": "Per-Layer UV Exposure-Dependent Cytotoxicity of 3D-Printed Aligner Resins and Estrogen-like Activity Screening",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:22:24Z",
  "url": "https://research.draconitic.com/paper/0dh67q3xe6tpa",
  "venue": "Polymers",
  "versions": []
}