This is an unedited manuscript accepted for publication and provided as an Article in Press for early access at the author’s request. The article will undergo copyediting, typesetting, and galley proof review before final publication. Please be aware that errors may be identified during production that could affect the content. All legal disclaimers of the journal apply.
Amir Khan,
Piyush Singhal,
- Phd Scholar, Department of Mechanical Engineering GLA university, Mathura, Uttar Pradesh, India
- Professor, Department of Mechanical Engineering GLA university, Mathura, Uttar Pradesh, India
Abstract
Dental resin composites are widely used in restorative dentistry because of their excellent aesthetics, conservative cavity preparation, and satisfactory mechanical properties. However, their long-term clinical performance is limited by polymerization shrinkage, wear, microcrack formation, water absorption, and degradation in the oral environment. This study investigates the mechanical and morphological characteristics of Halloysite Nanotube (HNT)-reinforced Urethane Dimethacrylate (UDMA) dental composites to enhance the structural performance and durability of restorative materials. UDMA-based composites containing different concentrations of HNTs were fabricated using controlled mixing and light-curing techniques. Their flexural strength, flexural modulus, compressive strength, Vickers microhardness, and water sorption behavior were evaluated. Morphological characterizations were performed using Scanning Electron Microscopy (SEM). The experimental results demonstrated that low to moderate HNT loadings significantly improved the mechanical performance of the composites by enhancing stress transfer, crack deflection, and filler matrix interactions. Increased microhardness indicated superior surface durability and wear resistance. SEM observations revealed uniform nanotube dispersion at lower filler concentrations, whereas higher HNT loadings resulted in particle agglomeration, increased viscosity, and localized void formation, adversely affecting mechanical performance. The findings confirm that HNTs are effective nano reinforcements for UDMA dental composites when incorporated at optimized concentrations and uniformly dispersed within the resin matrix. The developed nanocomposites exhibit enhanced stiffness, hardness, and fracture resistance, demonstrating considerable potential for advanced restorative dentistry. Future investigations should focus on long-term aging, simulated oral wear, antibacterial performance, cytocompatibility, and clinical validation to establish their suitability for next-generation dental restorative applications.
Keywords: Halloysite nanotubes (HNTs), dental composites, restorative dentistry, mechanical characterization.
References
1. J. L. Ferracane, Resin composite State of the art, Dental Materials. 27(1):29–38, Jan. 2011, doi: 10.1016/j.dental.2010.10.020.
2. M. M. Gad, R. Abualsaud, A. M. Rahoma, A. M. Al-Thobity, M. Al-Harbi, and M. A. Akhtar, Dental resin composites: A review on materials to product realizations, Polymers. 14(5. 1000. 2022. doi: 10.3390/polym14051000.
3. H. Y. Marghalani, Resin-based dental composite materials, in Advanced Dental Biomaterials, B. Ben-Nissan, Ed. Cham, Switzerland: Springer, 2019:357–405.
4. Y. Lvov, W. Wang, L. Zhang, and R. Fakhrullin, Halloysite clay nanotubes for loading and sustained release of functional compounds, Advanced Materials. 28(6):1227–1250. 2016. doi: 10.1002/adma.201502341.
5. R. Sakaguchi and J. M. Powers, Craig’s Restorative Dental Materials, 14th ed. St. Louis, MO, USA: Elsevier. 2019.
6. J. W. Nicholson, Polymer-Based Dental Materials. Cham, Switzerland: Springer. 2020.
7. I. Sideridou, V. Tserki, and G. Papanastasiou, Effect of chemical structure on degree of conversion in light-cured dimethacrylate-based dental resins, Biomaterials. 23(8):1819–1829. 2002. doi: 10.1016/S0142-9612(01)00308-8.
8. J. Gajewski, M. Pfeifer, N. Fróes-Salgado, A. Boaro, and R. R. Braga, Monomers used in resin composites: Degree of conversion, mechanical properties and water sorption/solubility, Brazilian Dental Journal. 23(5):508–514. 2012.
9. R. R. Braga, R. Y. Ballester, and J. L. Ferracane, Factors involved in the development of polymerization shrinkage stress in resin composites: A systematic review, Dental Materials. 21(10):962–970. 2005. doi: 10.1016/j.dental.2005.04.018.
10. R. Ilie and R. Hickel, Resin composite restorative materials, Australian Dental Journal. 56;Suppl 1:59–66. 2011. doi: 10.1111/j.1834-7819.2010.01296.x.
11. S. Deb, Dental Materials at a Glance, 2nd ed. Hoboken, NJ, USA: Wiley-Blackwell. 2018.
12. S. Mitra, H. Wu, and B. N. Holmes, An application of nanotechnology in advanced dental materials, Journal of the American Dental Association. 134(10):1382–1390. 2003. doi: 10.14219/jada.archive.2003.0054.
13. K. S. Sodagar, A. Bahador, M. Khalil, S. Shahroudi, and M. Zaman Kassaee, The effect of TiO₂ and SiO₂ nanoparticles on mechanical properties of dental composites: A review, Journal of Prosthodontic Research. 60(3):151–159. 2016.
14. A. Besinis, T. De Peralta, and R. D. Handy, The antibacterial effects of nanostructured dental restorative materials: A review, Journal of Dentistry. 42(9):1012–1023. 2014.
15. R. S. Ahmed and M. A. A. Mohamed, Nanofillers as reinforcement agents for dental resin composites: A comprehensive review, Journal of Composite Materials. 55(20):2897–2918. 2021.
16. E. Abdullayev and Y. Lvov, Halloysite clay nanotubes as a ceramic nanocontainer for biomedical and pharmaceutical applications, Journal of Materials Chemistry B. 1(23):2894–2903. 2013. doi: 10.1039/C3TB20169H.
17. Y. Lvov, E. Abdullayev, and A. Fakhrullin, Functional polymer–clay nanotube composites with sustained release of chemical agents, Progress in Polymer Science. 38(10–11:1690–1719. 2013. doi: 10.1016/j.progpolymsci.2013.05.009.
18. R. Fakhrullin and Y. Lvov, Halloysite clay nanotubes for tissue engineering and drug delivery, Nanomedicine. 11(17):2243–2246. 2016.
19. E. Joussein, S. Petit, D. Churchman, B. Theng, R. Righi, and B. Delvaux, Halloysite clay minerals—A review, Clay Minerals. 40(4):383–426. 2005. doi: 10.1180/0009855054040180.
20. P. Yuan, D. Tan, and F. Annabi-Bergaya, Properties and applications of halloysite nanotubes: Recent research advances and future prospects, Applied Clay Science. 112–113:75–93. 2015. doi: 10.1016/j.clay.2015.05.001.
21. M. Massaro, G. Lazzara, S. Milioto, R. Noto, and S. Riela, Halloysite nanotubes: A sustainable nanomaterial for biomedical, environmental and industrial applications, Journal of Materials Chemistry B. 6(3):341–363. 2018. doi: 10.1039/C7TB02521A.
22. X. Chen, M. D. Weir, H. H. K. Chow, M. A. Melo, L. Cheng, and H. H. K. Xu, Nanotechnology in dental restorative materials: Advances and perspectives, International Journal of Nanomedicine. 11:107–121. 2016.
23. M. D. Weir, H. H. K. Xu, M. A. S. Melo, and L. Cheng, Nanocomposite dental materials for clinical applications, Dental Materials Journal. 36(5):561–572. 2017.
24. L. Cheng, M. D. Weir, H. H. K. Xu, A. M. Kraigsley, N. J. Lin, S. Lin-Gibson, and X. Zhou, Antibacterial and physical properties of calcium-phosphate and nanocomposite dental restorative materials: A review, Dental Materials. 28(5):561–572. 2012.
25. E. Abdullayev, R. Joshi, W. Wei, Y. Zhao, and Y. Lvov, Enlargement of halloysite clay nanotube lumen by selective etching of aluminum oxide, ACS Nano. 6(8):7216–7226. 2012. doi: 10.1021/nn302678a.
26. P. Pasbakhsh, G. J. Churchman, and J. L. Keeling, Halloysite nanotubes: Properties, synthesis, and applications in polymer nanocomposites, Applied Clay Science. 74:47–57. 2013. doi: 10.1016/j.clay.2012.06.014.
27. P. Yuan, D. Tan, and F. Annabi-Bergaya, Halloysite nanotubes: Natural nanomaterials for advanced functional applications, Journal of Materials Chemistry A. 3(13):7299–7310. 2015. doi: 10.1039/C4TA06444D.
28. J. L. Ferracane, Hygroscopic and hydrolytic effects in dental polymer networks, Dental Materials. 22(3):211–222. 2006. doi: 10.1016/j.dental.2005.05.005.
29. A. Alshali, N. Salim, J. Satterthwaite, and N. Silikas, Post-irradiation changes in degree of conversion and mechanical properties of bulk-fill and conventional resin composites, Journal of Dentistry. 43(2):209–217. 2015. doi: 10.1016/j.jdent.2014.12.008.
30. L. M. dos Santos, A. C. F. M. Costa, R. R. Braga, and F. R. Tay, Water sorption, solubility and stability of contemporary dental resin composites: A systematic review, Journal of the Mechanical Behavior of Biomedical Materials. 119, 104518. 2021. doi: 10.1016/j.jmbbm.2021.104518.
31. R. R. Braga and J. L. Ferracane, Alternatives in polymerization contraction stress management, Critical Reviews in Oral Biology & Medicine. 15(3):176–184. 2004. doi: 10.1177/154411130401500306.
32. A. D. Parolia, M. A. Thomas, R. Kundabala, and V. Mohan, Recent advances in resin-based dental restorative materials, Journal of Clinical and Diagnostic Research. 11(8):ZE01–ZE05. 2017.
33. M. Massaro, G. Lazzara, S. Milioto, R. Noto, and S. Riela, Halloysite nanotubes as nanocarriers and reinforcing agents in polymer-based biomaterials, Applied Clay Science. 160:186–193. 2018.
34. S. C. Bayne, J. Y. Thompson, E. J. Swift Jr., P. Stamatiades, and W. Wilkerson, A characterization of first-generation flowable composites, Journal of the American Dental Association. 129(5):567–577. 1998.
35. C. A. Stansbury, Dimethacrylate network formation and polymerization behavior in dental resins, Dental Materials. 28(1):13–22. 2012.
36. A. D. Karabela and G. E. Sideridou, Synthesis and study of properties of dental resin composites with different nanosilica particles and silane coupling agents, Dental Materials. 27(8):825–835. 2011. doi: 10.1016/j.dental.2011.04.008.
37. M. Du, B. Guo, and D. Jia, Preparation and characterization of halloysite nanotube/polymer nanocomposites: A review, Polymer International. 59(5):574–582. 2010. doi: 10.1002/pi.2754.
38. M. Liu, B. Guo, M. Du, Y. Chen, and D. Jia, Halloysite nanotubes as a novel β-nucleating agent for polypropylene: Preparation, characterization and mechanical properties, Polymer. 49(13–14:3029–3037. 2008. doi: 10.1016/j.polymer.2008.04.045.
39. J. W. Nicholson and B. Czarnecka, Materials for the Direct Restoration of Teeth. Cambridge, U.K.: Woodhead Publishing. 2016.
40. ISO 4049:2019, Dentistry—Polymer-Based Restorative Materials. Geneva, Switzerland: International Organization for Standardization. 2019.
41. M. Du, B. Guo, and D. Jia, Thermomechanical properties, morphology, and fracture behavior of halloysite nanotube/polymer nanocomposites, European Polymer Journal. 42(6):1362–1369. 2006.
42. T. D. Fornes and D. R. Paul, Modeling properties of nylon 6/clay nanocomposites using composite theories, Polymer. 44(17):4993–5013. 2003.
43. R. L. Sakaguchi and J. M. Powers, Craig’s Restorative Dental Materials, 15th ed. St. Louis, MO, USA: Elsevier. 2024.
44. P. Pasbakhsh, G. J. Churchman, and J. L. Keeling, Characterisation of properties and morphology of halloysite nanotubes relevant to their use as nanotube fillers, Applied Clay Science. 74:47–57. 2013. doi: 10.1016/j.clay.2012.06.014.
45. ASTM E384-22, Standard Test Method for Microindentation Hardness of Materials. West Conshohocken, PA, USA: ASTM International. 2022.
46. I. M. Low, Hardness Testing: Principles and Applications. Materials Park, OH, USA: ASM International. 2008.
47. T. Liu, M. Tjiu, Y. Tong, C. He, and S. S. Yee, Morphology and fracture behavior of halloysite nanotube-reinforced polymer nanocomposites, Composites Science and Technology. 68(7–8:1810–1816. 2008.
48. J. K. Kim and Y. W. Mai, Engineered Interfaces in Fiber Reinforced Composites. Oxford, U.K.: Elsevier. 1998.
49. ISO 4049:2019, Dentistry—Polymer-Based Restorative Materials. Geneva, Switzerland: International Organization for Standardization. 2019.
50. C. H. S. Toledano, M. Osorio, F. S. Osorio, F. S. S. Osorio, and R. Carvalho, Water sorption and solubility of resin-based restorative dental materials: Influence on hydrolytic degradation and clinical performance, Dental Materials. 23(6):742–748. 2007.
51. J. I. Goldstein, D. E. Newbury, J. R. Michael, N. W. M. Ritchie, J. H. J. Scott, and D. C. Joy, Scanning Electron Microscopy and X-Ray Microanalysis, 4th ed. New York, NY, USA: Springer. 2018.
52. D. Hull and T. W. Clyne, An Introduction to Composite Materials, 2nd ed. Cambridge, U.K.: Cambridge University Press. 1996.
Journal of Polymer & Composites
| Volume | 14 | |
| 04 | ||
| Received | 17/08/2026 | |
| Accepted | 07/09/2026 | |
| Published | 19/09/2026 | |
| Publication Time | 33 Days |