title: Influence of number of dental autoclave treatment cycles on rotational performance of commercially available air-turbine handpieces.
abstract: The influence of number of autoclave treatment cycles (N) on rotational speed and total indicated run-out of commercially available air-turbine handpieces from five manufacturers was investigated at N=0, 50, 100, 150, 200, 250 and 300 cycles, and the significance in the test results was assessed by Dunnett's multiple comparison test. Some air-turbine handpieces showed the significant differences in rotational speed at N=300 cycles, however, the decreases of the rotational speeds were only 1 to 3.5 percent. Some air-turbine handpieces showed the significant differences in total indicated run-out, however, the respective values were smaller than that at N=0 cycle. Accordingly, it can be considered that the ball bearing in the air-turbine handpieces is not affected significantly by autoclave. To further evaluate rotational performance, this study focused on the rotational vibration of the ball bearing components of the air-turbine, as measured by Fast Fourier Transform (FFT) analysis; the power spectra of frequency of the ball's revolution, frequency of the cage's rotation and frequency of the ball's rotation were comparatively investigated at N=0, 150 and 300 cycles, and the influence of autoclave was evaluated qualitatively. No abnormalities in the ball bearings were recognized.
authors.affiliation: Department of Biodesign, Division of Biosystems, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nagai
authors.forename: Kazuo
authors.initials: K
authors.lastname: Takakuda
mesh_terms: D002516:Ceramics; D003754:Dental High-Speed Equipment / Q000592:standards; D004867:Equipment Design; D005583:Fourier Analysis; D006358:Hot Temperature; D006801:Humans; D008422:Materials Testing; D012399:Rotation; D013232:Steel; D013242:Sterilization / Q000295:instrumentation / Q000379:methods*; D013499:Surface Properties
chemical_list: D013232:Steel