[Cyclic fatigue of GI-II glass infiltrated ceramic in Hertzian's contact].
OBJECTIVE
To investigate the cyclic fatigue damage modes of GI-II glass infiltrated ceramic in Hertzian's contact.


METHODS
All ceramic specimens were loaded by a r=3.18 mm WC ball to investigate their cyclic fatigue behavior in Hertzian's contact. Furthermore, the surviving stress was examined by three-point-flexure-test and morphological damages were observed. All statistical analysis were performed with one-way ANOVA. For all tests, a P-value less than 0.05 was considered to be significant.


RESULTS
The strength of the specimens decreased from 395.7+/-46.5MPa to 318.6+/-40.3MPa after the 1st cycle when the load was 900N, 203.6+/-18.7MPa after 10(5) cycles, and 170+/-33.9MPa after 2 x 10(5) cycles. There was significant difference from that of the cycles (P<0.05). According to the loading cycles, the fatigue damage represented bend in loading area, worm-eaten abrasion or exfoliation around loading area and sequent massive exfoliation. But there was not significant different between the 1st cycle and the 105 cycles when the load was 500N.


CONCLUSIONS
In Hertzian's contact,the fatigue damage mode is characterized by a quasi-plastic mode caused by crack tip shield and crystal bridging decline which are driven by shear and tensile stress.
Liu
Wei-cai
WC
Department of Prosthodontics, School of Stomatology, Tongji University, Shanghai 200072, China. vogi@163.com
Shen
Xia
X
Wu
Jun-hua
JH
Fan
Zheng
Z
Chao
Yong-lie
YL
D003776:Dental Porcelain; D019232:Dental Restoration Failure; D005898:Glass; D008422:Materials Testing
D003776:Dental Porcelain