Load-bearing capacity and the recommended thickness of dental monolithic zirconia single crowns

Ting Sun; Shanyu Zhou; Renfa Lai; Ruoyu Liu; Shuyuan Ma; Zhiying Zhou; Shao Longquan

doi:10.1016/j.jmbbm.2014.03.014

Load-bearing capacity and the recommended thickness of dental monolithic zirconia single crowns

J Mech Behav Biomed Mater. 2014 Jul:35:93-101. doi: 10.1016/j.jmbbm.2014.03.014. Epub 2014 Apr 2.

Authors

Ting Sun¹, Shanyu Zhou², Renfa Lai¹, Ruoyu Liu², Shuyuan Ma¹, Zhiying Zhou¹, Shao Longquan³

Affiliations

¹ The Medical Centre of Stomatology, the 1st Affiliated Hospital of Jinan University, Guangzhou 510630, China.
² Department of Stomatology, Nanfang Hospital, Southern Medical University, No.1838, North of Guangzhou Street, Guangzhou 510515, Guangdong, China.
³ Department of Stomatology, Nanfang Hospital, Southern Medical University, No.1838, North of Guangzhou Street, Guangzhou 510515, Guangdong, China. Electronic address: shaolongquan@smu.edu.cn.

PMID: 24762856
DOI: 10.1016/j.jmbbm.2014.03.014

Abstract

Purpose: The aim of this study was to evaluate the load bearing capacity and a reasonable thicknesss of dental monolithic zirconia crowns.

Materials and methods: Polymethyl methacrylate (PMMA) abutment tooth specimens were made by CAD/CAM technic. Monolithic zirconia crowns (MZC), monolithic lithium disilicate crowns (MLC), layered zirconia crowns (LZC) and metal ceramic crowns(MCC), of which the occlusal thickness was 1.5mm were thereafter fabricated and cemented on the abutment tooth specimens. MCC with occlusal thicknesses of 0.6mm, 0.8mm, 1.00mm, 1.2mm were also made. All specimens underwent load-to-fracture test. Weibull parameters (σ0) and (m) were calculated. Fracture modes were also evaluated.

Results: The mean fracture load was 1863.16±116.81 for MLC, 2284.77±355.60 for MCC, 2308.0±510.94 for LZC, 4109.93±610.18 for MZC (1.5mm), 3068.31±233.88 for MZC (1.2mm), 2429.88±315.03 for MZC (1.0mm), 1814.60±68.21 for MZC (0.8mm) and 1308.38±111.38 for MZC (0.6mm). The fracture load of MZC was significantly higher than MCC, LZC and MLC (P<0.05). The fracture loads for MCC with different thickness were significantly different (P<0.05). Similar trend was observed for the characteristic strength (σ0) and Weibull modulus (m). For MZC and MLC, the fracture mode was catastrophic failure. The predominant fracture mode for LZC was catastrophic fracture. The fracture loads of MZC(1.0mm) and MCC were not statistically different (P>0.05).

Conclusions: Monolithic zirconia crowns exhibit higher fracture loads than monolithic lithium disilicate crowns, layered zirconia crowns and metal ceramic crowns. The fracture resistance of monolithic zirconia crowns with a thickness of 1.0mm can be equal to metal ceramic crowns. Doubling the monolithic zirconia core from 0.6mm to 1.5mm increases the fracture resistance of this restorative system threefold.

Keywords: Fracture load; Monolithic; Single crown; Thickness; Zirconia.

Publication types

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

MeSH terms

Cementation
Ceramics
Crowns*
Dental Cements
Dental Prosthesis Design / methods*
Dental Restoration Failure*
Dental Stress Analysis / methods*
Humans
Lithium / chemistry
Materials Testing
Metal Ceramic Alloys / chemistry*
Microscopy, Electron, Scanning
Stress, Mechanical
Tooth / ultrastructure
Weight-Bearing*
Zirconium / chemistry*

Substances

Dental Cements
Metal Ceramic Alloys
Lithium
Zirconium
zirconium oxide