Author/Editor		Kosmač, Tomaž; Oblak, Čedomir; Jevnikar, Peter; Funduk, Nenad; Marion, Ljubo
Title		Strength and reliability of surface treated Y-TZP dental ceramics
Type		članek
Source		J Biomed Mater Res
Vol. and No.		Letnik 53, št. 4
Publication year		2000
Volume		str. 304-13
Language		eng
Abstract		This work was undertaken to evaluate the effects of dental grinding and sandblasting on the biaxial flexural strength and Weibull modulus of various Y-TZP ceramics containing 3 mol% yttria. In addition, the susceptibility of pristine and mechanically treated materials to low-temperature degradation under the conditions adopted for testing the chemical solubility of dental ceramics was investigated. The results revealed that surface grinding and sandblasting exhibit a counteracting effect on the strength of Y-TZP ceramics. Dental grinding lowered the mean strength and Weibull modulus, whereas sandblasting provided a powerful method for strengthening, but at the expense of somewhat lower reliability. The finest-grained material exhibited the highest strength after sintering, but it was less damage tolerant than tougher, coarse- grained materials. Upon extraction with the acetic acid solution and the ammonia solution, a significant amount of tetragonal zirconia had transformed to monoclinic, but extensive microcracking and attendant strength degradation had not yet occurred. Standard grade Y-TZP ceramics are more resistant in an alkaline than in an acidic environment, and there was a strong grain-size dependence of the diffusion- controlled transformation. Since a special Y-TZP grade containing a small amount of alumina exhibited the highest damage tolerance and superior stability in an acidic environment, this material shows considerable promise for dental applications.
Descriptors		DENTAL PORCELAIN ZIRCONIUM YTTRIUM MATERIALS TESTING HARDNESS TESTS SURFACE PROPERTIES DENTAL POLISHING PLIABILITY ELASTICITY CORROSION X-RAY DIFFRACTION ACETIC ACID AMMONIA MICROSCOPY, ELECTRON, SCANNING