Improper Curing of 3D Printed Restorations and Intraoral Degradation: Microplastic Release Health Risks and the Role of Oxygen-Free Polymerisation
Main Article Content
Abstract
Three-dimensional (3D) printing technology has significantly revolutionised the field of restorative dentistry by facilitating the remarkably swift and highly accurate production of customised dental restorations tailored to meet individual patient needs and specifications. Nevertheless, a growing body of evidence increasingly underscores the presence of substantial health risks that are associated with the intraoral degradation of resin-based materials that have not been appropriately cured during the manufacturing process. The phenomenon of incomplete polymerisation—often a consequence of factors such as oxygen inhibition, insufficient exposure to light, or the implementation of suboptimal curing protocols—results in the release of residual monomers and microplastics into the oral cavity, thereby raising serious concerns. These released substances are progressively being recognised as biologically active contaminants that possess the potential to induce a variety of adverse effects, including cytotoxicity, oxidative stress, endocrine disruption, and inflammatory responses that can impact both local tissues within the oral cavity and systemic tissues throughout the body. This comprehensive review aims to synthesise the most current research regarding the chemical and mechanical consequences that arise from inadequate curing processes, the biological pathways that are affected by the ingestion of microplastics and the leaching of monomers, and the broader implications this has for the long-term safety and well-being of patients undergoing such dental procedures. Various strategies that have been proposed—including oxygen-free polymerisation techniques, the use of optimised curing wavelengths (for example, at 385 nm), and the development of modified resin formulations—are discussed as potential means to effectively mitigate these significant health risks associated with dental materials. The findings presented in this review emphasise the pressing necessity for the establishment of standardised protocols and the pursuit of further research endeavours aimed at addressing the concealed health burden that is posed by the degradation of 3D printed dental restorations in the context of clinical dentistry. Ultimately, addressing these challenges will require a collaborative effort among researchers, clinicians, and manufacturers to enhance the safety and efficacy of dental materials in restorative practices.
Keywords:
3D printing in dentistry; resin-based restorations; improper curing; oxygen inhibition; microplastic release; intraoral degradation; polymerisation; biocompatibility; endocrine disruption; dental material safety
Article Details
How to Cite
NULTY, Adam Brian; ZACHRISSON, Patrik Magnus.
Improper Curing of 3D Printed Restorations and Intraoral Degradation: Microplastic Release Health Risks and the Role of Oxygen-Free Polymerisation.
Medical Research Archives, [S.l.], v. 13, n. 7, july 2025.
ISSN 2375-1924.
Available at: <https://esmed.org/MRA/mra/article/view/6684>. Date accessed: 05 dec. 2025.
doi: https://doi.org/10.18103/mra.v13i7.6684.
Section
Research Articles
The Medical Research Archives grants authors the right to publish and reproduce the unrevised contribution in whole or in part at any time and in any form for any scholarly non-commercial purpose with the condition that all publications of the contribution include a full citation to the journal as published by the Medical Research Archives.
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14. Covernton GA, Davies HL, Cox K, et al. A Bayesian analysis of the factors determining microplastics ingestion in fishes. J Hazard Mater. 2021;413: 125405. doi:10.1016/j.jhazmat.2021.125405.
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25. Hajjaj MS, Alamoudi RAA, Babeer WA, et al. Flexural strength, flexural modulus and microhardness of milled vs. fused deposition modeling printed zirconia; effect of conventional vs. speed sintering. BMC Oral Health. 2024;24(1):[page number not available]. doi:10.1186/s12903-023-03829-8.
26. Heris YS. Bacterial biodegradation of synthetic plastics: a review. Bull Natl Res Cent. 2024;48(1): [page number not available]. doi:10.1186/s42269-024-01241-y.
27. Ilie N. Degradation of dental methacrylate based composites in simulated clinical immersion media. J Funct Biomater. 2022;13(1):25. doi:10.3390/jfb13 010025.
28. Jiang J. Occurrence of microplastics and its pollution in the environment: a review. Sustain Prod Consump. 2017;13:16. doi:10.1016/j.spc.20 17.11.003.
29. John N, Salim R. Biodegradation of plastics by microbes a review. AIP Conf Proc. 2020;2263: 20003. doi:10.1063/5.0016828.
30. Kumar R, Manna C, Padha S, et al. Micro(nano)plastics pollution and human health: how plastics can induce carcinogenesis to humans? Chemosphere. 2022;298:134267. doi:10.1016/j.ch emosphere.2022.134267.
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32 Leggat PA, Kedjarune U. Toxicity of methyl methacrylate in dentistry. Int Dent J. 2003;53 (3):126. doi:10.1111/j.1875-595x.2003.tb00736.x.
33. Li Y, Tao L, Wang Q, Wang F, Li G, Song M. Potential health impact of microplastics: a review of environmental distribution, human exposure, and toxic effects. Environ Health. 2023;1(4):249. doi:10.1021/envhealth.3c00052.
34. Mahran GA, El Banna A, El Korashy DI. Evaluation of a 3D printed nanohybrid resin composite versus a milled resin composite for flexural strength, wear and color stability. BMC Oral Health. 2025;25(1):[page number not available]. doi:10.1186/s12903-025-05861-2.
35. Marigo L, Nocca G, Fiorenzano G, et al. Influences of different air inhibition coatings on monomer release, microhardness, and color stability of two composite materials. Biomed Res Int. 2019; 2019:1. doi:10.1155/2019/4240264.
36. Martos J, Osinaga PWR, Oliveira E de, Castro LAS de. Hydrolytic degradation of composite resins: effects on the microhardness. Mater Res. 2003;6 (4):599. doi:10.1590/s1516-14392003000400029.
37. Microplastics are everywhere — we need to understand how they affect human health. Nat Med. 2024;30(4):913. doi:10.1038/s41591-024-02968-x.
38. Nisha M, Montazer Z, Sharma P, Levin DB. Microbial and enzymatic degradation of synthetic plastics. Front Microbiol. 2020;11. doi:10.3389/fmi cb.2020.580709.
39. Oberoi G, Nitsch S, Edelmayer M, Janjić K, Müller AS, Agis H. 3D printing—encompassing the facets of dentistry. Front Bioeng Biotechnol. 2018;6. doi:10.3389/fbioe.2018.00172.
40. Oliveira J, Belchior A, Silva VD da, et al. Marine environmental plastic pollution: mitigation by microorganism degradation and recycling valorization. Front Mar Sci. 2020;7. doi:10.3389/fm ars.2020.567126.
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