Advisory Committee Chair
Gregg M Janowski
Advisory Committee Members
John O Burgess
Nathaniel C Lawson
Robin D Foley
Gregory B Thompson
Document Type
Dissertation
Date of Award
2015
Degree Name by School
Doctor of Philosophy (PhD) School of Engineering
Abstract
This investigation addresses the issue that yttria stabilized zirconia is being used as a dental biomaterial without substantial evidence of its long-term viability. Furthermore, stabilized zirconia (SZ) undergoes low temperature degradation (LTD), which can lead to roughening of the surface. A rougher exterior can lead to increased wear of the antagonist in the oral environment. Despite the LTD concerns, SZ is now widely used in restorative dentistry, including full contour crowns. A comparison of aging methods to determine the role of artificial aging on inducing the transformation has not been extensively studied. Therefore, simulations of the transformation process were investigated by comparing different methods of accelerated aging. The rejected null hypothesis is that the temperature of aging treatment will not affect the time required to cause measurable monoclinic transformation of yttria stabilized zirconia. The transformation of SZ starts at the surface and progresses inward; however, it is unclear whether the progression is constant for different aging conditions. This investigation analyzed the depth of transformation as a function of aging conditions for stabilized zirconia in the top 5-6 µm from the surface. The rejected null hypothesis is that the transformation amount is constant throughout the first six micrometers from the surface. The effects of grain size on the amount of monoclinic transformation were also investigated. This study aimed to determine if the grain size of partially stabilized zirconia affects the amount of monoclinic transformation, surface roughness, and property degradation due to aging. The rejected null hypothesis is that the grain size will not affect the amount of monoclinic transformation, thus have no effect on surface roughening or property degradation. The final part of this study addresses the wear of enamel when opposing zirconia by observing how grain size and aging affected the wear rate of an enamel antagonist. The rejected null hypothesis is that neither zirconia grain size, nor aging condition affects the wear of an enamel antagonist.
Recommended Citation
Lucas, Thomas J., "Analysis Of Tetragonal To Monoclinic Phase Transformation Caused By Accelerated Artificial Aging And The Effects Of Microstructure In Stabilized Zirconia" (2015). All ETDs from UAB. 2347.
https://digitalcommons.library.uab.edu/etd-collection/2347