Objective. This study compared the cutting efficiency of different diamond rotary cutting instruments on twoceramic materials when used with an electric handpiece versus an air-turbine handpiece. The amount of surface roughness exhibited by an electric hand-piece was also evaluated in comparison with an air-turbine hand-piece, when used to cut through ceramic restorative materials in a simulated crown removal procedure. Materials and Methods.One-hundred and sixty ceramic specimens were fabricated from lithium disilicate (IPS e.max Press, Ivoclar Vivadent, Amherst, NY) and zirconium oxide (ZirCAD, Ivoclar Vivadent, Amherst, NY) with standardized dimensions (5mm x 2mm x 20mm). Samples were divided into eight groups according to diamond burs types (coarse and fine) and type of handpiece used. There were twenty samples in each group. A standardized cutting system, comprised of an air turbine handpiece (Gentleforce LUX 6000B, Kavo America, Lake Zurich, IL) or an electric handpiece (MASTERmatic LUX M25 L High Speed, Kavo America, Lake Zurich, IL), mounted in a brass cylinder attached to an L-shaped, clear acrylic resin vertical block by a frictionless bearing, was used for sectioning. A cutting force of 0.90 N (102.1 g) was applied to the handpiece at the diamond and ceramic specimen interface. A total of eighty cuts were performed in each group. Four cuts were made in each substrate with each bur type, using a different bur for each block with each cut being timed to 0.1 second to measure cutting efficiency. Cutting efficiency was determined as mm/min. These data were analyzed using a one-way analysis ofvariance (ANOVA) test with significance set at p 0.05). The electric handpiece exhibited a significantly faster rate when cutting through lithium disilicate using fine diamond burs (p
| Date of Award | Jan 1 2018 |
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| Original language | English |
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| Supervisor | Sharon Siegel (Supervisor), Jeffrey Y. Thompson (Advisor) & Marvin Golberg (Advisor) |
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