COMPARISON OF CUTTING EFFICIENCIES BETWEEN ELECTRIC AND AIR-TURBINE DENTAL HANDPIECES

Statement of problem. Dentistry is gravitating toward the increased use of electric handpieces. The dental professional should have sufficient evidence to validate the switch from an air-turbine handpiece to an electric handpiece. However, there is little research quantifying the cutting efficiency of electric and air-turbine handpieces. Studies that do quantify cutting efficiency typically do so with only a single material. Purpose. The purpose of this study was to compare the cutting efficiency of an electric handpiece and an air-turbine handpiece, using various materials commonly used in dentistry. Material and methods. Seven materials: Macor (machinable glass ceramic), silver amalgam, aluminum oxide, zirconium oxide, high noble metal alloy, noble metal alloy, and base metal alloy, were each cut with a bur 220 times; 1 10 times with an electric handpiece, and 110 times with an air-turbine handpiece. The weight difference of the material was calculated by subtracting the weight of the material after a cut from the weight of the material before the cut. The cutting efficiency was calculated by dividing the weight difference by the duration of the cut (g/s). Data were analyzed by a 2-way analysis of variance followed by Tukey's Honestly Significant Difference (HSD) test (alpha=.05). Results. The electric handpiece cut more efficiently than the air-turbine handpiece (F=3098.9, P<.001). In particular, the high noble metal alloy, silver amalgam, and Macor were cut more efficiently with the electric handpiece (0.0383 +/- 0.0002 g/s, 0.0260 +/- 0.0002 g/s, and 0.0122 +/- 0.0002 g/s, respectively) than with the air-turbine handpiece (0.0125 +/- 0.0002 g/s, 0.0142 +/- 0.0002 g/s, and 0.008 +/- 0.0002 g/s, respectively). Conclusions. The electric handpiece is more efficient at cutting various materials used in dentistry, especially machinable glass ceramic, silver amalgam, and high noble alloy, than the air-turbine handpiece. (J Prosthet Dent 2010;103:101-107)