Evidence map›Paper›PMID 42199088›Full record

ArticleEuropean journal of orthodontics2026

Effects of microplastic release from 3D-printed orthodontic aligners: a histological and immunological bioassay approach.

Marina Borgese, Piero Antonio Zecca, Annalisa Grimaldi, Nicolò Baranzini, Mario Raspanti, Francesca Zara, Marco Serafin, Alberto Caprioglio

Abstract read
In one paragraph

Article in European journal of orthodontics, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

8 authors.

Marina BorgeseDepartment of Medicine and Technological Innovation, University of Insubria, Via Guicciardini 9, Varese 21100, Italy.
Piero Antonio ZeccaDepartment of Medicine and Technological Innovation, University of Insubria, Via Guicciardini 9, Varese 21100, Italy.ORCID 0000-0001-9646-4958
Annalisa GrimaldiDepartment of Biotechnology and Health Sciences, University of Insubria, via J.H. Dunant 3, Varese 21100, Italy.ORCID 0000-0002-9258-7595
Nicolò BaranziniDepartment of Biotechnology and Health Sciences, University of Insubria, via J.H. Dunant 3, Varese 21100, Italy.
Mario RaspantiDepartment of Medicine and Technological Innovation, University of Insubria, Via Guicciardini 9, Varese 21100, Italy.
Francesca ZaraDepartment of Biomedical, Surgical and Dental Sciences, University of Milan, via della Commenda 10, Milan 20122, Italy.
Marco SerafinDepartment of Biomedical, Surgical and Dental Sciences, University of Milan, via della Commenda 10, Milan 20122, Italy.ORCID 0000-0003-4680-0989
Alberto CaprioglioDepartment of Biomedical, Surgical and Dental Sciences, University of Milan, via della Commenda 10, Milan 20122, Italy.ORCID 0000-0002-8264-7320

Funding

IRCCSItalian Ministry of Health
6 · The paper itself

Abstract

aimThis study investigated the acute biological effects of micro- and nanoplastics (MPs/NPs) released from 3D-printed orthodontic aligners, focusing on their potential to elicit inflammatory and oxidative responses. Given the dynamic intraoral environment, the use of a biologically relevant invertebrate model (Hirudo verbana) enabled histological and molecular assessment of short-term exposure to plastic-derived particles. MATERIALS AND

methodsMPs/NPs were generated from 3D-printed aligner samples via mechanical stress and ultrasonication. Medicinal leeches were exposed to the resulting plastic dispersion for 24, 72 h, and 1 week (triplicate experiments). Morphological alterations were assessed by light and electron microscopy. CD31 and HmAIF-1 immunostaining and acid phosphatase assays evaluated immunological responses. Oxidative stress was quantified by quantitative PCR (qPCR) analysis of SOD and GST gene expression. One-way ANOVA with Dunnett's post hoc test comparing MP/NP-treated vs controls (α = 0.05).

resultsExposure to MPs/NPs triggered rapid angiogenesis, confirmed by increased CD31 expression and vascular remodelling over time (24 h, P < .01; 72 h, P < .001; 1 week, P < .01). Macrophage-like cell activation was significantly evidenced by elevated HmAIF-1 levels (24 h, P < .001; 72 h, P < .01; 1-week, P < .001) and acid phosphatase activity (24 h, P < .001; 72 h, P < .01; 1-week, P < .001). Oxidative-stress markers (SOD and GST) were significantly upregulated at 24 h (P < .001) and, for glutathione transferase only, slightly increased at 72 h (P < .05), indicating an acute cellular stress response that decreased at later time points.

conclusionsEven brief exposure to MPs/NPs released from 3D-printed aligners can disrupt tissue homeostasis, activating inflammatory and oxidative pathways. These findings raise concerns about the biocompatibility of photopolymer resins and underscore the need for more dynamic, biologically relevant testing models to evaluate the safety of orthodontic materials under clinically realistic conditions.

Indexed as

Orthodontic AppliancesPlasticsPrinting, Three-DimensionalAcid PhosphataseAnimalsBiological AssayGlutathione TransferaseNeovascularization, PhysiologicOxidative StressPlatelet Endothelial Cell Adhesion Molecule-1Superoxide DismutaseTime FactorsAcid PhosphataseGlutathione TransferasePlasticsPlatelet Endothelial Cell Adhesion Molecule-1Superoxide Dismutase3D-printed alignersbiocompatibilityimmune responsemicro-nanoplasticsoxidative stress

Identifiers

PMID42199088
PMCPMC13213083

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LicenceCC BY
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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.