- 作者：Andrea Coldea ; Michael V. Swain ; Norbert Thiel
- 关键词：Vickers indentation ; Fracture toughness ; Dental ceramics ; Interpenetrating phase composite ; Flexural strength ; Strength degradation ; Damage tolerance
- 刊名：Journal of the Mechanical Behavior of Biomedical Materials
- 出版年：2013
- 出版时间：October, 2013
- 年：2013
- 卷：26
- 期：Complete
- 页码：34-42
- 全文大小：1165 K
Objectives
To determine the flexural strength and subsequent strength degradation of a range of dental CAD/CAM ceramic materials and novel PICN (Polymer-Infiltrated-Ceramic-Network) materials by means of pre-damaging with Vickers indentations at various loads.Methods
The materials tested included (Mark II, PICN test material 1 and 2, In-Ceram Alumina, VM 9, In-Ceram YZ; Vita Zahnfabrik, Bad Saeckingen, Germany) and (IPS e.max CAD, Ivoclar Vivadent, Schaan, Liechtenstein). Bending bars were cut and lapped with 15 ¦Ìm diamond suspension. Initial flexural strength (n=10) was determined in three-point-bending. To evaluate the damage tolerance, Vickers indentations were placed on the bending bars (n=35) with varying loads (1.96-98.07 N). The indented bending bars were subsequently loaded to fracture in three-point-bending. In addition, the fracture toughness was determined by the indentation strength (IS) and the SEVNB technique (n=5).
Results
With increasing indentation loads the fracture strength of all materials tested decreased. The material with the highest fracture resistance to indentation induced damage, was the PICN test material 1 with an indentation load-flexural strength curve slope of 0.21. In-Ceram YZ exhibited the highest damage susceptibility with a slope of 0.4. The fracture toughness varied with the measurement technique and material in the range of 0.82 (VM 9) to 4.94 (In-Ceram YZ) MPa¡Ìm for the SEVNB method and 0.96 (VM 9) to 4.97 (In-Ceram YZ) MPa¡Ìm for the IS method respectively.
Significance
This study aims to indicate the likely clinical behavior by evaluating the damage tolerance and R-curve behavior of dental ceramics by in-vitro strength degradation and fracture toughness measurements.