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SENIOR EDITORS
John W. Farah, D.D.S., Ph.D.
John M. Powers, Ph.D.
EDITOR-IN-CHIEF
Sabiha S. Bunek, D.D.S.
“Improving Patient Care Through Research & Education”
EDITORIAL BOARD
John A. Molinari, Ph.D
Peter Yaman, D.D.S., M.S.
William A. Gregory, D.D.S., M.S.
Santine Anderson, D.D.S.
Julius E. Bunek, D.D.S., M.S.
Lori K. Brown, D.D.S.
Marie Fluent, D.D.S.
Brent Kolb, D.D.S.
Nizar Mansour, D.D.S.
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Charles I. McLaren, D.D.S., M.S.
Kathy O’Keefe, D.D.S., M.S.
Thomas Poirier, D.D.S.
William T. Stevenson, D.D.S.
Robert J. Stevenson, D.D.S.
Gytis Udrys, D.D.S.
EXECUTIVE TEAM
Jackie Farah, M.A.Ed.
Heidi L. Graber
Tricia G. Hurtt
Jennifer N. Ireland, C.D.A, R.D.A.
Jennifer Kalasz
Craig Macfarlane
John A. Molinari, Ph.D
Peri D. Nelson
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Courtney Richardson, B.F.A.
Christopher Voigtman
Nelson Williams, M.S.
Mary E. Yakas, B.A., CMC
DIRECTOR OF RESEARCH
Ron Yapp, M.S.
THE DENTAL ADVISOR
3110 West Liberty
Ann Arbor, MI 48103
Toll free: 800.347.1330
E-mail: [email protected]
Web Site: www.dentaladvisor.com
NUMBER 42 - FEBRUARY 2012
Torque Versus Speed Characteristics of Three 45° Handpieces
R. Yapp, M.S., J.M. Powers, Ph.D.
THE DENTAL ADVISOR Biomaterials Research Center
Dental Consultants, Inc., Ann Arbor, Michigan
Purpose – The purpose of this project was to measure the torque versus speed characteristics of three different handpieces and to
compare their ability to perform under different loading scenarios and at different supply air pressures.
Experimental Design –
Handpieces: J. Morita TwinPower Turbine 45 (4H PAR-4HEX-O-45) [SN Z 30134]
NSK Titanium High Speed Air Turbine Handpiece (NL-45K-S) [SN CMY 01717]
Palisades Dental Impact Air 45 High Speed Handpiece [SN P51680]
Dependent variables: stall torque, torque versus speed curve
Independent variables: manufacturer’s highest recommended air pressure, 35 psi, 30 psi, and 25 psi
Materials and Methods – The handpieces were secured one at a time to THE DENTAL ADVISOR Handpiece Test Platform. The
brake rotor, a 1.60 mm diameter steel shank with a 6.35 mm diameter ball at one end, was inserted into the chuck of the handpiece,
which was then attached to the handpiece pivot assembly and adjusted so that the ball was aligned with the center of the torque
sensor turret. The speed of the brake rotor, which was painted longitudinally half black and half white, was measured with a infrared
speed sensor (Monarch) and tachometer (ACT 3 Electronic Tachometer). A silk thread was attached at one end to the load cell of an
universal testing machine (Instron 5866) on which the test platform was mounted and the other end wound around and attached to the
pulley (26.7 mm diameter) of the torque sensor turret. During the testing, the handpiece was pressed downward along the axis of the
chuck shaft with varying loads so that the brake rotor was pushed against the asbestos brake pad, which was attached to the top of the
torque sensor. The friction of the brake rotor against the brake pad produced a torque in the torque sensor, which was registered by the
load cell as a force. The torque was calculated as the product of this force times the radius of the turret pulley. Several torque versus
speed data points were taken to define the torque versus speed curve for each handpiece. Each torque versus speed curve was charted
on a single graph for each air pressure for comparison purposes. The stall torque was determined by pivoting the brake rotor into the
brake pad with enough force to stop the brake rotor. The torque so generated and measured by the force in the thread attached to the
load cell was defined as the stall torque. It can be read directly from the torque versus speed graphs at zero rpm.
Results –
Manufacturer’s Max Recommended Air Pressure
450000
A. Torque versus speed curves at manufacturer’s
maximum recommended air pressure
400000
350000
Note: Stall torque of the J. Morita TwinPower
Turbine 45 is 50% greater than either of the
other two handpieces.
300000
RPM
250000
200000
150000
100000
50000
0
-50000
0
0.5
J. Morita - 36 PSI
Torque, N-mm
1.0
Palisades Dental - 40 PSI
1.5
NSK - 40 PSI
Copyright ©2012, Dental Consultants, Inc. All rights reserved. Printed in the U.S.A. (ISSN 0748-4666)
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35 PSI
400000
400000
350000
350000
300000
300000
RPM
RPM
200000
150000
200000
150000
100000
100000
50000
50000
0
0
0
0.2
0.4
J. Morita
0.6
Torque, N-mm
0.8
1.0
-50000 0
1.2
NSK
Palisades Dental
0.5
1.0
Torque, N-mm
J. Morita
Palisades Dental
NSK
B. Torque versus speed curves at 35 psi
C. Torque versus speed curves at 30 psi
Note: At a supply air pressure of 35 psi, the stall torque
of the J. Morita TwinPower Turbine 45 was 63%
higher than the Palisades Dental Impact Air 45 High
Speed Handpiece and 48% higher than the NSK
Titanium High Speed Air Turbine Handpiece.
Note: At a supply air pressure of 30 psi, the stall torque
of the J. Morita TwinPower Turbine 45 was 64%
higher than the Palisades Dental Impact Air 45 High
Speed Handpiece and 11% higher than the NSK
Titanium High Speed Air Turbine Handpiece.
25 PSI
Air Pressure vs. RPM
350000
450000
300000
400000
250000
350000
300000
RPM
200000
RPM
T
250000
250000
150000
100000
250000
200000
150000
50000
100000
0
50000
-50000
R
30 PSI
450000
-50000
O
0
0.2
J. Morita
0.4
Torque, N-mm
0.6
Palisades Dental
0.8
NSK
D. Torque versus speed curves at 25 psi
0
0
10
J. Morita
20
30
40
Palisades Dental
NSK
Air Pressure, PSI
E. Handpiece supply air pressure versus rpm
Note: At a supply air pressure of 25 psi, the stall torque
of the J. Morita TwinPower Turbine 45 was 68%
higher than the Palisades Dental Impact Air 45 High
Speed Handpiece and 25% higher than the NSK
Titanium High Speed Air Turbine Handpiece.
Conclusions –
1. The J. Morita TwinPower Turbine 45 exhibited higher torque versus speed curves than the other two handpieces at
supply air pressures of 35, 30, and 25 psi.
2. The Palisades Dental Impact Air 45 High Speed Handpiece demonstrated the highest speed (410,000 RPM) at zero torque.
3. The J. Morita TwinPower Turbine 45 exhibited the highest stall torque of the three handpieces tested at all supply
air pressures tested.
This project was funded in part by J. Morita.
Copyright ©2012, Dental Consultants, Inc. All rights reserved. Printed in the U.S.A. (ISSN 0748-4666)
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