TY - JOUR
T1 - Variability of mechanical torque-limiting devices in clinical service at a US dental school
AU - McCracken, Michael S.
AU - Mitchell, Lillian
AU - Hegde, Rashmi
AU - Mavalli, Mahendra D.
N1 - Copyright:
Copyright 2010 Elsevier B.V., All rights reserved.
PY - 2010/1
Y1 - 2010/1
N2 - Purpose: The purpose of this study was to measure the variability of torque produced by a population of mechanical torque-limiting devices in clinical service in a US dental school. The torque-limiting devices were divided into two categories according to their mode of action: toggle-type and beam wrenches. Proper action of these devices is essential for calibrated delivery of preload to implant prosthetic screws. Materials and Methods: Seventeen torque-limiting devices (35 Ncm) were obtained from graduate prosthodontic, predoctoral, and faculty practice clinics. Nine of these were toggle-type devices, and eight were beam-type wrenches. Torque from each wrench was measured using an MGT electronic torque meter. Wrenches were tested in two modes, slow (over 4 seconds) and fast (over 1 second). Results: Toggle-type torque wrenches produced a mean (± SD) torque of 38.1 ± 16.0 Ncm; beam-type wrenches produced 32.8 ± 1.1 Ncm. These results were not significantly different. When tested in fast mode (1 second), toggle-type wrenches produced 28.0 ± 9.6 Ncm; in the slow mode (4 seconds) they produced significantly more force, 36.6 ± 14.0 Ncm (p < 0.001). Beam-type wrenches produced 33.2 ± 1.1 Ncm and 32.8 ± 1.1 Ncm in fast and slow modes, respectively. Conclusions: Both types of wrenches tested were capable of producing accurate torque values; however, variability was higher in the toggle-type group. Some toggle-type torque wrenches in clinical service delivered unacceptably high torque values. It is recommended that clinicians calibrate toggle-type wrenches frequently. Torque wrenches should be activated slowly, over 4 seconds, when using a correctly calibrated toggle-type wrench.
AB - Purpose: The purpose of this study was to measure the variability of torque produced by a population of mechanical torque-limiting devices in clinical service in a US dental school. The torque-limiting devices were divided into two categories according to their mode of action: toggle-type and beam wrenches. Proper action of these devices is essential for calibrated delivery of preload to implant prosthetic screws. Materials and Methods: Seventeen torque-limiting devices (35 Ncm) were obtained from graduate prosthodontic, predoctoral, and faculty practice clinics. Nine of these were toggle-type devices, and eight were beam-type wrenches. Torque from each wrench was measured using an MGT electronic torque meter. Wrenches were tested in two modes, slow (over 4 seconds) and fast (over 1 second). Results: Toggle-type torque wrenches produced a mean (± SD) torque of 38.1 ± 16.0 Ncm; beam-type wrenches produced 32.8 ± 1.1 Ncm. These results were not significantly different. When tested in fast mode (1 second), toggle-type wrenches produced 28.0 ± 9.6 Ncm; in the slow mode (4 seconds) they produced significantly more force, 36.6 ± 14.0 Ncm (p < 0.001). Beam-type wrenches produced 33.2 ± 1.1 Ncm and 32.8 ± 1.1 Ncm in fast and slow modes, respectively. Conclusions: Both types of wrenches tested were capable of producing accurate torque values; however, variability was higher in the toggle-type group. Some toggle-type torque wrenches in clinical service delivered unacceptably high torque values. It is recommended that clinicians calibrate toggle-type wrenches frequently. Torque wrenches should be activated slowly, over 4 seconds, when using a correctly calibrated toggle-type wrench.
KW - Implant
KW - Mechanical torque-limiting device
KW - Preload
KW - Torque wrench
UR - http://www.scopus.com/inward/record.url?scp=76649144483&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=76649144483&partnerID=8YFLogxK
U2 - 10.1111/j.1532-849X.2009.00524.x
DO - 10.1111/j.1532-849X.2009.00524.x
M3 - Article
C2 - 19765196
AN - SCOPUS:76649144483
SN - 1059-941X
VL - 19
SP - 20
EP - 24
JO - Journal of Prosthodontics
JF - Journal of Prosthodontics
IS - 1
ER -