Author/Editor     Oblak, Čedomir
Title     Vpliv brušenja in peskanja na mehanske lastnosti tetragonalne cirkonijeve oksidne keramike
Type     monografija
Place     Ljubljana
Publisher     Medicinska fakulteta
Publication year     1999
Volume     str. 64
Language     slo
Abstract     Zirconia ceramics has been shown to be a promising novel material in various fields of dentistry, but it's use is limited to prefabricated elements because of the technological requirements. The surfaces of these confectional elements must, however be ground or sandblasted to adjust a final form or to improve adhaesion during cementation. The purpose of our study was to evaluate the effect of grinding and sandblasting on the biaxial flexural strength and reliability of tetragonal zirconia ceramics. The aim of our work was also to determine the amount of the tetragonal - monoclinic transformation of zirconia after grinding or sandblasting with x-ray diffraction analysis. Six groups of samples were prepared from fine and six from coarse zirconia ceramic. For each group different mechanical surface treatment was applied to the top surface of the specimens. We also studied the effect of different succession of mechanical surface treatment (grinding, sandblasting) on flexural strength of zirconia ceramic. This study showed that all surface treatment procedures influenced the strength of zirconia. Both grinding procedures (with and without water spray) lowered the strength. We ascribe this to surfacecracks introduced by grinding and their effect is obviously prevailing over surface compressive stresses in ground samples. Sandblasting increased the strength, indicating that a thin transformed surface compressive layer contributes to considerable strengthening of the material, provided that no severe surface cracks are introduced during this operation. Sandblasting prior to dry grinding seems to be the most detrimental surface treatment investigated in this study, which reduces flexural strength the most and with the lowest Weibull's modulus in both materials. Sandblasting is an established laboratory procedure to improve adhesion of ceramic systems. (Abstract truncated at 2000 characters)
Descriptors     DENTAL MATERIALS
CERAMICS
ZIRCONIUM
TENSILE STRENGTH
MATERIALS TESTING
X-RAY DIFFRACTION
DENTAL POLISHING