The magnitude of cutting forces at high speed.
BACKGROUND
Previous research has used a range of cutting forces for preparing teeth, but there are no data available on the forces actually imposed while cutting teeth with high-speed handpieces.


OBJECTIVE
The purpose of this study was to measure the forces imposed while cutting teeth with tungsten carbide burs used in high-speed handpieces.


METHODS
Thirty-one dentists each cut 8 conventional class II MO and DO preparations in intact extracted third molars, by use of 2 different air turbine handpieces with different torque-speed characteristics. Two different flat fissure, plain and cross-cut tungsten carbide burs, cutting wet and dry in each handpiece/bur combination. The teeth were mounted in a custom-made transducer unit that displayed the forces imposed by the bur. Data were analysed with a 1-way ANOVA (alpha =.05) and Spearman correlation test.


RESULTS
The results showed that there was no significant difference in the applied force between plain and cross-cut burs, cutting wet or cutting dry, but there was a significant difference between the high and the lower torque handpieces. The higher torque handpiece was used at a mean cutting force of 1.44 N and the lower torque handpiece at 1.20 N (P<.002). The overall general mean force observed was 1.30 N.


CONCLUSIONS
It was concluded that the forces used in cutting teeth with the tungsten carbide burs tested related both to the type of the handpiece and to the forces chosen by clinical operators. There was no difference between the plain and cross-cut burs, there was no difference between the cutting wet or dry, and the higher torque handpiece required a higher mean cutting force.
Elias
Kanaan
K
Eastman Dental Institute For Oral Health Care Sciences, Department of Conservative Dentistry, University College London and Imperial College, University of London, United Kingdom. k.elias@eastman.ucl.ac.uk
Amis
Andrew A
AA
Setchell
Derrick J
DJ
D000704:Analysis of Variance; D003737:Dental Cavity Preparation / Q000145:classification / Q000295:instrumentation*; D003754:Dental High-Speed Equipment; D004867:Equipment Design; D006801:Humans; D018709:Statistics, Nonparametric; D013314:Stress, Mechanical; D013499:Surface Properties; D019415:Torque; D014159:Transducers; D017973:Tungsten Compounds / Q000737:chemistry; D014867:Water
D017973:Tungsten Compounds; D014867:Water; C002802:tungsten carbide