title: Dentin removal efficacy over time of the Buc-1 ultrasonic tip.
abstract: OBJECTIVE
  The purpose of this study was to determine the loss of efficacy over time of the Buc-1 ultrasonic tip in dentin blocks.
  
  
  METHODS
  An ultrasonic handpiece was mounted to the loading arm of a universal testing machine and a downward force of 15 g was applied in 20-sec cycles for a total of 30 min of instrumentation. Efficacy was measured by the change in weight of the dentin block to the nearest 0.01 mg after 2, 10, 20, and 30 minutes of instrumentation (n = 5 tips).
  
  
  RESULTS
  Dentin removal decreased significantly between 2 and 10 minutes of instrumentation with no further significant decrease after 20 or 30 minutes (1-factor analysis of variance: alpha = .05).
  
  
  CONCLUSIONS
  The evidence suggests there is a significant decrease in dentin removal efficacy of the Buc-1 tip after 10 minutes of instrumentation. Continued instrumentation for up to 30 minutes showed no further decrease in efficacy.
authors.affiliation: Department of Endodontics, University Of Missouri-Kansas City, School of Dentistry, Kansas City, Missouri, USA.
authors.forename: Kerri
authors.initials: K
authors.lastname: Lawlor
authors.forename: Chris
authors.initials: C
authors.lastname: Yelton
authors.forename: James
authors.initials: J
authors.lastname: Kulild
authors.forename: Mary P
authors.initials: MP
authors.lastname: Walker
mesh_terms: D003764:Dental Materials; D003799:Dental Stress Analysis / Q000295:instrumentation; D003804:Dentin / Q000648:ultrastructure*; D018130:Diamond; D004867:Equipment Design; D006801:Humans; D008422:Materials Testing; D018915:Root Canal Preparation / Q000295:instrumentation*; D013314:Stress, Mechanical; D013997:Time Factors; D014464:Ultrasonic Therapy / Q000295:instrumentation*
chemical_list: D003764:Dental Materials; D018130:Diamond