Date of Graduation

2016

Document Type

Thesis

Degree Type

MS

College

School of Dentistry

Department

Orthodontics

Committee Chair

Matthew S Bryington

Committee Co-Chair

Michael D Bagby

Committee Member

Bryan D Dye

Abstract

Objectives: To monitor the rate of diamond bur cutting through sintered yttria stabilized zirconia. Through this observation, we intend to determine which bur(s) exhibit the greatest cutting efficiency and if a decline exists over time.;Methods: Seven dental diamond burs were used in an air-turbine hand piece to cut sintered Yttria Stabilized Zirconia blocks (3Y-TZP) at a constant 0.9N force for five minutes. The distance traveled was measured by a Linear Variable Differential Transformer (LVDT) and recorded per time by a data acquisition device. Time was divided into 100-second intervals for comparison. Individual effects of bur, time periods, and depth on cutting efficiency were evaluated. Combined effect of bur and time periods was also evaluated.;Results: Statistically significant differences were found between bur, time period and depth on bur cutting efficiency of 3Y-TZP. Combined effect of bur and time period did not demonstrate a significant difference. Burs with medium, coarse, and super coarse diamond particles exhibited greater cutting efficiency of sintered 3Y-TZP than burs with fine diamond particles. Cutting efficiency of all burs was significantly greater within the initial 100 second cutting time period.;Conclusions: For removal of 3Y-TZP crowns intraorally via sectioning, the results of this study suggest it is best to use a diamond bur with medium, coarse or super coarse particle grit size and limit its use to 100 seconds in order to maximize cutting efficiency. The super coarse diamond had the greatest cutting efficiency throughout the 5-minute evaluation period. Future studies are needed to evaluate cutting efficiency after low temperature degradation (LTD) and surface manipulations on 3Y-TZP in order to duplicate exposure to the oral environment, and expanding the testing time beyond 5 minutes to determine if and when a second significant difference in cutting efficiency occurs.

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