234 Effects of Polishing on Zirconia Crowns

Thursday, March 22, 2012: 2 p.m. - 3:15 p.m.
Presentation Type: Poster Session
S. CLARK1, J. SIMON1, and L. DARNELL2, 1University of Tennessee, Memphis, TN, 2Restorative Dentistry, University of Tennessee, Memphis, TN
Objectives: Zirconia, zirconium dioxide (ZrO2), is the toughest and strongest material in dentistry today. Zirconia is known for its physical, chemical, and mechanical properties. (hardness, high strength, dimensional stability, wear resistance, resistant to corrosion, elastic modulus similar to steel, coefficient of thermal expansion similar to iron, and elevated fracture toughness)  In comparison of mechanical properties, zirconia has better properties than any other ceramic materials. It is resistant to acids, but can dissolve in hydrofluoric acid.  Because of these high mechanical properties, the effects of polishing and finishing zirconia crowns is important as it relates to the opposing dentition. The aim of this study was to evaluate the effects of polishing and finishing zirconia crowns after occlusal adjustment.  Methods: Zirconia crowns were cut mesial-distally for a flat surface using a handpiece and Brassler diamonds.  Sixteen flat surface zirconia pieces were mounted into acrylic and then scanned on a KLA Tencor Alpha-Step 500 surface profilometer with stylus force 17.0 mg to determine surface roughness from lab polish to roughened surface to re-polished surface in microns.  Four samples were in each group. Data was compared based the usage of four different polishing kits. Results: All of the polishing kits were found to successfully polish zirconia. However, each of the kits were not equal in their ability to polish these samples. Conclusions: Polishing zirconia is important to prevent excessive wear of the opposing dentition. Current zirconia polishing kits are successful in achieving a smooth polished zirconia surface.
This abstract is based on research that was funded entirely or partially by an outside source: University of Tennessee Alumni Research Fund

Keywords: Ceramics and Surfaces