Abstract
This study aimed to investigate the mechanical behavior of the tooth–class II restoration complex restored with composite resin, ceramic, amalgam, and gold using three-dimensional linear and non-linear finite element analyses (FEA). Previous FEA studies generally assumed linear mechanical properties and bonded interfaces between tooth and restorative materials, which differ from clinical reality, particularly for non-bonded restorations such as amalgam and gold. Therefore, in this study, non-linear mechanical properties and non-bonded contact conditions were adopted for different restorative materials. The results showed that the highest enamel and dentin stresses occurred in amalgam restorations, while the lowest were found in ceramic restorations. Amalgam and gold produced higher stress in enamel and dentin compared with composite resin and ceramic. The higher stress observed in amalgam and gold was mainly associated with the non-bonded (frictional) contact condition, because the stresses in these restorations remained below their reported yield strengths under the applied loading conditions. This study provides mechanical insights into the behavior of the tooth–class II restoration complex and offers a possible mechanical interpretation of previously reported clinical observations. These findings should be interpreted within the limitations of the finite element model and do not directly represent clinical outcomes.
Data availability
- The datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request. - All data generated or analysed during this study are included in this published article [and its supplementary information files].
References
Skorulska, A., Piszko, P., Rybak, Z., Szymonowicz, M. & Dobrzyński, M. Review on Polymer, ceramic and composite materials for CAD/CAM indirect restorations in Dentistry—Application, mechanical characteristics and comparison. Materials 14, 1592 (2021).
Warreth, A. & Elkareimi, Y. All-ceramic restorations: A review of the literature. Saudi Dent. J. 32, 365–372. https://doi.org/10.1016/j.sdentj.2020.05.004 (2020).
Sulaiman, T. A. Materials in digital dentistry—A review. J. Esthetic Restor. Dentistry. 32, 171–181. https://doi.org/10.1111/jerd.12566 (2020).
Reza Rezaie, H., Rizi, B., Rezaei Khamseh, H. & Öchsner, A. M. M. in A Review on Dental Materials 47–171Springer International Publishing, (2020).
Daghrery, A. et al. Dimensional accuracy of additive and subtractive manufactured ceramic-reinforced hybrid composite inlays: a CBCT-based in vitro study. Sci. Rep. 15, 6048 (2025).
Feilden, E. et al. 3D printing bioinspired ceramic composites. Sci. Rep. 7, 13759 (2017).
Van Nieuwenhuysen, J. P., D’Hoore, W., Carvalho, J. & Qvist, V. Long-term evaluation of extensive restorations in permanent teeth. J. Dent. 31, 395–405. https://doi.org/10.1016/S0300-5712(03)00084-8 (2003).
Beier, U. S., Kapferer, I. & Dumfahrt, H. Clinical long-term evaluation and failure characteristics of 1,335 all-ceramic restorations. International J. Prosthodontics 25 (2012).
Studer, S. P., Wettstein, F., Lehner, C., Zullo, T. G. & Schärer, P. Long-term survival estimates of cast gold inlays and onlays with their analysis of failures. J. Rehabil. 27, 461–472. https://doi.org/10.1046/j.1365-2842.2000.00540.x (2000).
Nor, F. M., Teh, Z. S. & Kurniawan, D. Finite element analysis on mechanical performance of amalgam, gold, and bioglass dental filling materials in molar tooth. Materials Today: Proceedings, (2023). https://doi.org/10.1016/j.matpr.2023.04.201
Asmussen, E., Peutzfeldt, A., Class, I., Class & and II restorations of resin composite: an FE analysis of the influence of modulus of elasticity on stresses generated by occlusal loading. Dent. Mater. 24, 600–605. https://doi.org/10.1016/j.dental.2007.06.019 (2008).
Tantbirojn, D., Versluis, A., Pintado, M. R., DeLong, R. & Douglas, W. H. Tooth deformation patterns in molars after composite restoration. Dent. Mater. 20, 535–542. https://doi.org/10.1016/j.dental.2003.05.008 (2004).
Seo, D. G., Yi, Y. A., Shin, S. J. & Park, J. W. Analysis of factors associated with cracked teeth. J. Endod. 38, 288–292. https://doi.org/10.1016/j.joen.2011.11.017 (2012).
Babaei, B. et al. The effect of dental restoration geometry and material properties on Biomechanical behaviour of a treated molar tooth: A 3D finite element analysis. J. Mech. Behav. Biomed. Mater. 125, 104892. https://doi.org/10.1016/j.jmbbm.2021.104892 (2022).
Masoudi Nejad, R. et al. Fracture behavior of restored teeth and cavity shape optimization: numerical and experimental investigation. J. Mech. Behav. Biomed. Mater. 124, 104829. https://doi.org/10.1016/j.jmbbm.2021.104829 (2021).
Babaei, B., Cella, S., Farrar, P., Prentice, L. & Prusty, B. G. The influence of dental restoration depth, internal cavity angle, and material properties on Biomechanical resistance of a treated molar tooth. J. Mech. Behav. Biomed. Mater. 133, 105305. https://doi.org/10.1016/j.jmbbm.2022.105305 (2022).
Ausiello, P., Rengo, S., Davidson, C. L. & Watts, D. C. Stress distributions in adhesively cemented ceramic and resin-composite class II inlay restorations: A 3D-FEA study. Dent. Mater. 20, 862–872. https://doi.org/10.1016/j.dental.2004.05.001 (2004).
Ausiello, P. et al. Mechanical behavior of bulk direct composite versus block composite and lithium disilicate indirect class II restorations by CAD-FEM modeling. Dent. Mater. 33, 690–701. https://doi.org/10.1016/j.dental.2017.03.014 (2017).
Kim, S. Y., Kim, B. S., Kim, H. & Cho, S. Y. Occlusal stress distribution and remaining crack propagation of a cracked tooth treated with different materials and designs: 3D finite element analysis. Dent. Mater. 37, 731–740. https://doi.org/10.1016/j.dental.2021.01.020 (2021).
Jiang, W., Bo, H., YongChun, G. & LongXing, N. Stress distribution in molars restored with inlays or onlays with or without endodontic treatment: A three-dimensional finite element analysis. J. Prosthet. Dent. 103, 6–12. https://doi.org/10.1016/S0022-3913(09)60206-7 (2010).
Wakabayashi, N., Ona, M., Suzuki, T. & Igarashi, Y. Nonlinear finite element analyses: advances and challenges in dental applications. J. Dent. 36, 463–471. https://doi.org/10.1016/j.jdent.2008.03.010 (2008).
Lin, C. L., Chang, C. H., Wang, C. H., Ko, C. C. & Lee, H. E. Numerical investigation of the factors affecting interfacial stresses in an MOD restored tooth by auto-meshed finite element method. J. Oral Rehabil. 28, 517–525. https://doi.org/10.1046/j.1365-2842.2001.00689.x (2001).
Chun, K. J. & Lee, J. Y. Comparative study of mechanical properties of dental restorative materials and dental hard tissues in compressive loads. J. Dent. Biomech. 5, 1758736014555246. https://doi.org/10.1177/1758736014555246 (2014).
Sakaguchi, R. L. F. J. L. P. J. M. Craig’s restorative dental materials / edited by Ronald Sakaguchi, Jack Ferracane, John Powers (Elsevier, 2019).
Parsa, R. Z., Goldstein, G. R., Barrack, G. M. & LeGeros, R. Z. An in vitro comparison of tensile bond strengths of noble and base metal alloys to enamel. J. Prosthet. Dent. 90, 175–183. https://doi.org/10.1016/S0022-3913(03)00411-6 (2003).
Abreu, A. et al. Tensile bond strength of an adhesive resin cement to different alloys having various surface treatments. J. Prosthet. Dent. 101, 107–118. https://doi.org/10.1016/S0022-3913(09)60004-4 (2009).
Sen, D., Nayir, E. & Pamuk, S. Comparison of the tensile bond strength of high-noble, noble, and base metal alloys bonded to enamel. J. Prosthet. Dent. 84, 561–566. https://doi.org/10.1067/mpr.2000.110265 (2000).
Arola, D., Galles, L. A. & Sarubin, M. F. A comparison of the mechanical behavior of posterior teeth with amalgam and composite MOD restorations. J. Dent. 29, 63–73. https://doi.org/10.1016/S0300-5712(00)00036-1 (2001).
Sajewicz, E. & Kulesza, Z. A new tribometer for friction and wear studies of dental materials and hard tooth tissues. Tribol. Int. 40, 885–895. https://doi.org/10.1016/j.triboint.2006.09.006 (2007).
Gomes de Oliveira, S., Seraidarian, P. I., Landre, J. Jr., Oliveira, D. D. & Cavalcanti, B. N. Tooth displacement due to occlusal contacts: a three-dimensional finite element study. J. Oral Rehabil. 33, 874–880. https://doi.org/10.1111/j.1365-2842.2006.01670.x (2006).
Yang, H. et al. Stress distribution in premolars restored with inlays or onlays: 3D finite element analysis. J. Adv. Prosthodont. 10, 184–190. https://doi.org/10.4047/jap.2018.10.3.184 (2018).
Lin, C. L., Chang, Y. H. & Liu, P. R. Multi-factorial analysis of a cusp-replacing adhesive premolar restoration: A finite element study. J. Dent. 36, 194–203. https://doi.org/10.1016/j.jdent.2007.11.016 (2008).
Morikawa, A. Investigation of occlusal force on lower first molar in function]. Kokubyo Gakkai Zasshi. 61, 250–274. https://doi.org/10.5357/koubyou.61.250 (1994).
Acknowledgements
The authors thank ANSYS Inc. for providing the ANSYS software to Yonsei University, which enabled the finite element analysis in this study. This work was supported by a grant from the Yonsei University College of Dentistry, Seoul, Republic of Korea. The authors also acknowledge the Department of Conservative Dentistry, Yonsei University Dental Hospital, for technical assistance.
Funding
This study was supported by the Yonsei University College of Dentistry Fund (6-2017-0023).
Author information
Authors and Affiliations
Contributions
Y. H. Y. performed the finite element modelling and analysis and drafted the manuscript. M. J. J. contributed to the validation and interpretation of the results. S. J. S. assisted in the study design and supervised the analytical procedures. J. W. P. conceived and designed the study, revised the manuscript critically for important intellectual content, and approved the final version. All authors reviewed and approved the final manuscript.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing interests.
Additional information
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Supplementary Information
Below is the link to the electronic supplementary material.
Rights and permissions
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
About this article
Cite this article
Yu, YH., Jeon, MJ., Shin, SJ. et al. Mechanical behavior of tooth-class II restoration complex with various restorative materials using linear and non-linear finite element analysis. Sci Rep (2026). https://doi.org/10.1038/s41598-026-40204-3
Received:
Accepted:
Published:
DOI: https://doi.org/10.1038/s41598-026-40204-3
