Biomechanical behavior of fiber-reinforced and bulk-fill composites in extensive class II restorations: a three-dimensional finite element analysis
DOI:
https://doi.org/10.2340/biid.v13.46067Keywords:
Finite element analysis, biomechanics, dental restoration, biomimetic restorative material, fiber-reinforced compositeAbstract
Introduction: Owing to the complexity of dental architecture and the ongoing development of restorative materials, the biomechanical behavior within restored dental structures is not yet fully understood.
Objective: This study aimed to evaluate and compare the stress distribution in extensive Class II restorations reinforced with different composite systems using 3D-Finite Element Analysis (FEA).
Materials and Methods: A sound human mandibular first molar was digitized to generate a 3D solid model. Five experimental groups with mesio-occluso-distal (MOD) restorations were simulated: G1, bulk-fill composite core; G2, short fiber–reinforced composite (SFRC) core; G3, ultra-high molecular weight polyethylene (UHMWPE) fiber–reinforced core; C−, conventional nanohybrid composite; and C+, intact sound tooth. All restored groups received an occlusal and proximal veneering layer of conventional nanohybrid resin. A vertical load of 600 N was applied, and von Mises and maximum principal stresses were calculated.
Results: The UHMWPE group exhibited the most favorable stress distribution, demonstrating the lowest stress concentrations in the coronal tooth structure (353.5 MPa) and the adhesive interface (11.10 MPa). Conversely, the SFRC group presented the highest stress values in the remaining tooth structure (359.9 MPa), while the bulk-fill group recorded elevated stress peaks within the veneering material (21.29 MPa). Notably, the polyethylene core absorbed the highest internal stress (13.31 MPa) compared to the other experimental groups.
Conclusions: The type of structural reinforcement significantly dictates the biomechanics of Class II restorations. A core reinforced with polyethylene fibers (Ribbond THM) demonstrates a superior capacity to manage stress in high-load areas compared to SFRC (EverX Posterior) and bulk-fill composite (Tetric N-Ceram bulk fill).
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References
Garoushi S, Säilynoja E, Frater M, Keulemans F, Vallittu PK, Lassila L. A comparative evaluation of commercially available short fiber-reinforced composites. BMC Oral Health. 2024;24(1):1573. DOI: https://doi.org/10.1186/s12903-024-05267-6
Jakab A, Palkovics D, Szabó VT, Szabó B, Vincze-Bandi E, Braunitzer G, et al. Mechanical performance of extensive restorations made with short fiber-reinforced composites without coverage: a systematic review of in vitro studies. Polymers. 2024;16(5):590. DOI: https://doi.org/10.3390/polym16050590
Daher R, Ardu S, Di Bella E, Rocca GT, Feilzer AJ, Krejci I. Fracture strength of non-invasively reinforced MOD cavities on endodontically treated teeth. Odontology. 2021;109(2):368–75. DOI: https://doi.org/10.1007/s10266-020-00552-6
Alvanforoush N, Palamara J, Wong RH, Burrow MF. Comparison between published clinical success of direct resin composite restorations in vital posterior teeth in 1995–2005 and 2006–2016 periods. Aust Dent J. 2017;62(2):132–45. DOI: https://doi.org/10.1111/adj.12487
Alshabib A, Silikas N, Watts DC. Properties of model E-glass fiber composites with varying matrix monomer ratios. Dent Mater. 2024;40(3):441–50. DOI: https://doi.org/10.1016/j.dental.2023.12.002
Aminoroaya A, Neisiany RE, Khorasani SN, Panahi P, Das O, Madry H, et al. A review of dental composites: challenges, chemistry aspects, filler influences, and future insights. Compos Part B Eng. 2021;216(1):108852. DOI: https://doi.org/10.1016/j.compositesb.2021.108852
Bienias B, Kostrzewa-Janicka J, Wróbel-Bednarz K, Strużycka I. Comparative assessment of a light-curable dental composite reinforced with artificial fibers. Polymers (Basel). 2024;16(21):2970. DOI: https://doi.org/10.3390/polym16212970
Lempel E, Őri Z, Kincses D, Lovász BV, Kunsági-Máté S, Szalma J. Degree of conversion and in vitro temperature rise of pulp chamber during polymerization of flowable and sculptable conventional, bulk-fill and short-fibre reinforced resin composites. Dent Mater. 2021;37(6):983–97. DOI: https://doi.org/10.1016/j.dental.2021.02.013
Mossad Hassan Negm H, Yousry Elkharadly D, Badawy S, Rashad Omar Taha R. Fracture resistance in fibre-reinforced resin composite restorations in deciduous and permanent molars: an ex vivo study. Saudi Dent J. 2024;36(9):1197–202. DOI: https://doi.org/10.1016/j.sdentj.2024.06.017
Yang J, Silikas N, Watts DC. Polymerization and shrinkage kinetics and fracture toughness of bulk-fill resin-composites. Dent Mater. 2022;38(12):1934–41. DOI: https://doi.org/10.1016/j.dental.2022.10.002
Alshabib A, Silikas N, Algamaiah H, Alayad AS, Alawaji R, Almogbel S, et al. Effect of fibres on physico-mechanical properties of bulk-fill resin composites. Polymers (Basel). 2023;15(16):3452. DOI: https://doi.org/10.3390/polym15163452
Salem MN, Hassanein OE, ElKassas DW, Shaalan OO. 12-months clinical evaluation of fiber reinforced bulk fill resin composite versus incremental packing of nanohybrid resin composite in restoration of deep proximal lesions of permanent molars: a randomized controlled trial. Acta Stomatol Croat. 2022;56(3):267–80. DOI: https://doi.org/10.15644/asc56/3/5
Salem MN, Ghallab OH, Anwar MN, Elkassas DW. Effect of different formulations of dentin replacement materials and aging on the flexural strength of the overlying resin composite. J Dent Mater Tech. 2022;11(1):19–27.
Oksanen V, Bijelic-Donova J, Vallittu PK, Lassila L, Garoushi S. Two different short fiber-reinforced resin composites for extensive MOD cavities in premolars and molars. Clin Oral Investig. 2025;29(10):462. DOI: https://doi.org/10.1007/s00784-025-06562-4
Tsertsidou V, Mourouzis P, Dionysopoulos D, Pandoleon P, Tolidis K. Fracture resistance of class II MOD cavities restored by direct and indirect techniques and different materials combination. Polymers (Basel). 2023;15(16):3413. DOI: https://doi.org/10.3390/polym15163413
Jafarnia S, Valanezhad A, Shahabi S, Abe S, Watanabe I. Physical and mechanical characteristics of short fiber-reinforced resin composite in comparison with bulk-fill composites. J Oral Sci. 2021;63(2):148–51. DOI: https://doi.org/10.2334/josnusd.20-0436
Cruzado-Oliva FH, Vega-Anticona A, Ortiz-Diaz DA, Alarco-Jurado LC, Arbildo-Vega HI. Current perspective on fiberglass posts length: finite element study. Odovtos Int J Dent Sci. 2024;26(3):205–14. DOI: https://doi.org/10.15517/ijds.2024.61452
Pineda-Vélez E, Yadalam PK, Ardila CM. Efficacy of the finite element analysis in assessing the effects of light curing on the mechanical properties of direct restorative composites: a systematic review. J Clin Exp Dent. 2024;16(11):e1411–21. DOI: https://doi.org/10.4317/jced.62021
Mohammadi R, Alkurt Kaplan S, Harmankaya A, Gönder HY. Investigation of stress distribution and fatigue performance in restored teeth using different thicknesses of adhesive materials and different restorative materials: 3D finite element analysis (FEM). Materials (Basel). 2025;18(16):3888. DOI: https://doi.org/10.3390/ma18163888
Fidancioğlu YD, Alkurt Kaplan S, Mohammadi R, Gönder HY. Three-dimensional finite element analysis (FEM) of tooth stress: the impact of cavity design and restorative materials. Appl Sci. 2025;15(17):9677. DOI: https://doi.org/10.3390/app15179677
Neri H, Aripin D, Muryani A, Dharsono HDA, Yolanda Y, Mahyuddin AI. Stress analysis on mesiolingual cavity of endodontically treated molar restored using bidirectional fiber-reinforced composite (wallpapering technique). Clin Cosmet Investig Dent. 2024;16(1):75–89. DOI: https://doi.org/10.2147/CCIDE.S450325
Bansal P, Seth T, Kumar M, Bhatt M, Arora P, Gupta I, et al. Comparative evaluation of stress distribution and deformation in class II cavities restored with two different biomimetic restorative materials: a three-dimensional finite element analysis. Cureus. 2024;16(9):e69179. DOI: https://doi.org/10.7759/cureus.69179
Jung MK, Jeon MJ, Kim JH, Son SA, Park JK, Seo DG. Comparison of the stress distribution in base materials and thicknesses in composite resin restorations. Heliyon. 2024;10(3):e25040. DOI: https://doi.org/10.1016/j.heliyon.2024.e25040
Kim SY, Kim BS, Kim H, Cho SY. Occlusal stress distribution and remaining crack propagation of a cracked tooth treated with different materials and designs: 3D finite element analysis. Dent Mater. 2021;37(4):731–40. DOI: https://doi.org/10.1016/j.dental.2021.01.020
Arya A, Grewal MS, Arya V, Choudhary E, Duhan J. Stress distribution of endodontically treated mandibular molars with varying amounts of tooth structure restored with direct composite resin with or without cuspal coverage: a 3D finite element analysis. J Conserv Dent. 2023;26(1):20–5. DOI: https://doi.org/10.4103/jcd.jcd_333_22
Rahmayanti ZA, Aripin D, Muryani A, Yolanda Y, Dharsono HDA, Mihradi S, et al. Stress distribution of endodontically treated tooth MOD cavity restored with ribbon fiber-reinforced composite (wallpapering technique) using finite element method. Clin Cosmet Investig Dent. 2024;16(1):91–9. DOI: https://doi.org/10.2147/CCIDE.S450458
Paruchuri H, Ballullaya SV, Vadamodalu AK, Shankar P, Donthireddy BKR. Stress analysis of biomimetic restorations under thermomechanical loading using three-dimensional finite element analysis. J Conserv Dent Endod. 2025;28(10):1038. DOI: https://doi.org/10.4103/JCDE.JCDE_493_25
Deliperi S, Alleman D, Rudo D. Stress-reduced direct composites for the restoration of structurally compromised teeth: fiber design according to the ‘wallpapering’ technique. Oper Dent. 2017;42(3):233–43. DOI: https://doi.org/10.2341/15-289-T
Selvaraj H, Krithikadatta J. Fracture resistance of endodontically treated teeth restored with short fiber reinforced composite and a low viscosity bulk fill composite in class II mesial-occlusal-distal access cavities: an ex-vivo study. Cureus. 2023;15(8):e42798. DOI: https://doi.org/10.7759/cureus.42798
Gönder H, Mohammadi R, Harmankaya A, Yüksel İ, Fidancıoğlu Y, Karabekiroğlu S. Teeth restored with bulk–fill composites and conventional resin composites; investigation of stress distribution and fracture lifespan on enamel, dentin, and restorative materials via three-dimensional finite element analysis. Polymers (Basel). 2023;15(7):1637. DOI: https://doi.org/10.3390/polym15071637
Duarte JCL, Costa AR, Veríssimo C, Duarte RW, Calabrez Filho S, Spohr AM, et al. Interfacial stress and bond strength of bulk-fill or conventional composite resins to dentin in class II restorations. Braz Dent J. 2020;31(5):532–9. DOI: https://doi.org/10.1590/0103-6440202003338
Aliberti A, Caggiano M, Piscopo M, Gasparro R, Cernera M, Armogida NG, et al. Finite element analysis in polymer-based adhesive dental restorations: a narrative review on material behavior, methodological validity, and clinical relevance. Polymers (Basel). 2026;18(5):580. DOI: https://doi.org/10.3390/polym18050580
Kozák V, Vala J, Derevianko A. Modelling structural material damage using the cohesive zone approach under operational conditions. Materials (Basel). 2025;18(17):4039. DOI: https://doi.org/10.3390/ma18174039
Pedram P, Jafarnia S, Shahabi S, Saberi S, Hajizamani H. Comparative evaluation of fiber-reinforced, bulk-fill and conventional dental composites: physical characteristics and polymerization properties. Polim Med. 2022;52(1):13–8. DOI: https://doi.org/10.17219/pim/151857
Tuncdemir MT, Yeşilyurt NG, Arıkan M. Comparison of the stress distribution in class I and Class II amalgam and bulk-fill composite restorations using CAD-FEM modeling. Int J Periodontics Restorative Dent. 2021;41(1):e1–9. DOI: https://doi.org/10.11607/prd.5024
Escobar LB, Pereira da Silva L, Manarte-Monteiro P. Fracture resistance of fiber-reinforced composite restorations: a systematic review and meta-analysis. Polymers (Basel). 2023;15(18):3802. DOI: https://doi.org/10.3390/polym15183802
Kamourieh N, Faigenblum M, Blizard R, Leung A, Fine P. Fracture toughness of short fibre-reinforced composites – in vitro study. Materials (Basel). 2024;17(21):5368. DOI: https://doi.org/10.3390/ma17215368
Wayakanon K, Totiam P, Naorungroj S. Effect of short fiber-reinforced resin-based composite on fracture resistance of extensive direct restorations: a systematic review and network meta-analysis. J Prosthet Dent. 2026;135(2):277. DOI: https://doi.org/10.1016/j.prosdent.2025.09.034
Metwaly A, Zoghby A, Abd Elaziz R. Clinical performance of polyethylenefiber reinforced resin composite restorations in endodontically treated teeth: (a randomized controlled clinical trial). BMC Oral Health. 2024;24(1):1285. DOI: https://doi.org/10.1186/s12903-024-05009-8
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