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Monolithic crowns fracture analysis: The effect of material properties, cusp angle and crown thickness.
Dent Mater. 2020 08; 36(8):1038-1051.DM

Abstract

OBJECTIVES

This study aimed to investigate the collective influence of material properties and design parameters on the fracture behavior of monolithic dental crowns.

METHODS

Three-dimensional (3D) models (N=90) with different combinations of design parameters (thickness, cusp angle and occlusal notch geometry) and material type (lithium disilicate, feldspar ceramic, zirconia, hybrid resin ceramic and hybrid polymer-infiltrated ceramic) were developed for the failure analysis using extended finite element method (XFEM) to identify the stress distribution, crack initiation load, fracture surface area and fracture pattern. Analytical formulation, in vitro fracture tests and fractographic analysis of dedicated models were also performed to validate the findings of the XFEM simulation.

RESULTS

For all material types considered, crowns with a sharp occlusal notch design had a significantly lower fracture resistance against occlusal loading. In most of the models, greater crown thickness and cusp angle resulted in a higher crack initiation load. However, the effect of cusp angle was dominant when the angle was in the low range of 50° for which increasing thickness did not enhance the crack initiation load.

SIGNIFICANCE

Comparing the critical load of crack initiation for different models with the maximum biting force revealed that for the studied monolithic materials excluding zirconia, a design with a rounded occlusal notch, 70° cusp angle and medium thickness (1.5mm occlusal) is an optimum combination of design parameters in terms of tooth conservation and fracture resistance. Zirconia crowns exhibited sufficient strength for a more conservative design with less thickness (1.05mm occlusal) and sharper cusp angle (60°).

Links

Publisher Full Text (DOI)

Authors+Show Affiliations

Shahmoradi M
School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW 2006, Australia. Electronic address: mahdi.shahmoradi@sydney.edu.au.
Wan B
School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW 2006, Australia. Electronic address: bwan9310@uni.sydney.edu.au.
Zhang Z
School of Engineering, Western Sydney University, Penrith, NSW 2751, Australia. Electronic address: leo.zhang@westernsydney.edu.au.
Wilson T
School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW 2006, Australia. Electronic address: twil8481@uni.sydney.edu.au.
Swain M
School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW 2006, Australia. Electronic address: michael.swain@sydney.edu.au.
Li Q
School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW 2006, Australia. Electronic address: qing.li@sydney.edu.au.

MeSH

CeramicsCrownsDental PorcelainDental Prosthesis DesignDental Restoration FailureDental Stress AnalysisMaterials TestingZirconium

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

32534794

Citation

Shahmoradi, Mahdi, et al. "Monolithic Crowns Fracture Analysis: the Effect of Material Properties, Cusp Angle and Crown Thickness." Dental Materials : Official Publication of the Academy of Dental Materials, vol. 36, no. 8, 2020, pp. 1038-1051.
Shahmoradi M, Wan B, Zhang Z, et al. Monolithic crowns fracture analysis: The effect of material properties, cusp angle and crown thickness. Dent Mater. 2020;36(8):1038-1051.
Shahmoradi, M., Wan, B., Zhang, Z., Wilson, T., Swain, M., & Li, Q. (2020). Monolithic crowns fracture analysis: The effect of material properties, cusp angle and crown thickness. Dental Materials : Official Publication of the Academy of Dental Materials, 36(8), 1038-1051. https://doi.org/10.1016/j.dental.2020.04.022
Shahmoradi M, et al. Monolithic Crowns Fracture Analysis: the Effect of Material Properties, Cusp Angle and Crown Thickness. Dent Mater. 2020;36(8):1038-1051. PubMed PMID: 32534794.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Monolithic crowns fracture analysis: The effect of material properties, cusp angle and crown thickness. AU - Shahmoradi,Mahdi, AU - Wan,Boyang, AU - Zhang,Zhongpu, AU - Wilson,Tom, AU - Swain,Michael, AU - Li,Qing, Y1 - 2020/06/11/ PY - 2019/10/14/received PY - 2020/04/18/revised PY - 2020/04/30/accepted PY - 2020/6/15/pubmed PY - 2020/12/15/medline PY - 2020/6/15/entrez KW - Cusp angle KW - Extended finite element analysis KW - Material property KW - Monolithic dental crown KW - Thickness SP - 1038 EP - 1051 JF - Dental materials : official publication of the Academy of Dental Materials JO - Dent Mater VL - 36 IS - 8 N2 - OBJECTIVES: This study aimed to investigate the collective influence of material properties and design parameters on the fracture behavior of monolithic dental crowns. METHODS: Three-dimensional (3D) models (N=90) with different combinations of design parameters (thickness, cusp angle and occlusal notch geometry) and material type (lithium disilicate, feldspar ceramic, zirconia, hybrid resin ceramic and hybrid polymer-infiltrated ceramic) were developed for the failure analysis using extended finite element method (XFEM) to identify the stress distribution, crack initiation load, fracture surface area and fracture pattern. Analytical formulation, in vitro fracture tests and fractographic analysis of dedicated models were also performed to validate the findings of the XFEM simulation. RESULTS: For all material types considered, crowns with a sharp occlusal notch design had a significantly lower fracture resistance against occlusal loading. In most of the models, greater crown thickness and cusp angle resulted in a higher crack initiation load. However, the effect of cusp angle was dominant when the angle was in the low range of 50° for which increasing thickness did not enhance the crack initiation load. SIGNIFICANCE: Comparing the critical load of crack initiation for different models with the maximum biting force revealed that for the studied monolithic materials excluding zirconia, a design with a rounded occlusal notch, 70° cusp angle and medium thickness (1.5mm occlusal) is an optimum combination of design parameters in terms of tooth conservation and fracture resistance. Zirconia crowns exhibited sufficient strength for a more conservative design with less thickness (1.05mm occlusal) and sharper cusp angle (60°). SN - 1879-0097 UR - https://www.unboundmedicine.com/medline/citation/32534794/Monolithic_crowns_fracture_analysis:_The_effect_of_material_properties_cusp_angle_and_crown_thickness_ DB - PRIME DP - Unbound Medicine ER -