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Title The Accuracy Of Mechanical Torque Devices For Implants Used In Dental Offices
Clinical Question In an adult patient with a loose implant screw, will an unused mechanical torque device tighten the implant screw with greater precision than a used mechanical torque device?
Clinical Bottom Line The torque devices tested revealed considerable differences in accuracy, suggesting that the prescribed applied torque amounts may not be as reliable as hoped for. Unfortunately, the evidence is somewhat weak. (See Comments on the CAT below)
Best Evidence (you may view more info by clicking on the PubMed ID link)
PubMed ID Author / Year Patient Group Study type
(level of evidence)
#1) 21210000Santos/2011Clinicians’ mechanical torque devices. N = 16Laboratory Study
Key resultsThis article compared measured values to standard values and found that there was some acceptable deviation from those standard values, and for the most part, torque devices that were evaluated were considered accurate enough according to 10 dental offices, while 2 offices reported values higher than the target torque, and 4 offices reported values lower than the target torque.
#2) 15508992Cehreli/2004Clinicians’ mechanical torque devices. N = 15Laboratory Study
Key results"New torque devices applied higher values than used devices for the 35 Ncm torque target (P < .05)." Devices that had been used 500 to 1000 times applied torques that were approximately 1.5 Ncm lower than the targeted 35 Ncm torque value and 1 Ncm lower than the targeted 15 Ncm torque value.
#3) 18672124Vallee/2008Clinicians’ mechanical torque devices. N = 30Laboratory Study
Key resultsThis article reported that the mean absolute difference and the mean percentage deviation between measured torque values and target torque values differed significantly (P<.001) for “friction-style mechanical torque limiting devices” and for “spring-style mechanical torque limiting devices (0.82 Ncm, 2.36%).”
Evidence Search Search torque limiting device Search accuracy of torque application deviceSearch torque application device
Comments on
The Evidence
The evidence presented in these articles appears valid and has some significance in helping dentists recognize the importance of calibrating mechanical torque devices.
Applicability The evidence provided by these articles is applicable to most if not all specialties of dentistry, particularly with patients receiving implants.
Specialty/Discipline (General Dentistry) (Orthodontics) (Periodontics) (Prosthodontics)
Keywords Dental implants, dental implantation, endosseous instrumentation, equipment design, equipment reuse, materials testing, torque
ID# 834
Date of submission: 04/06/2011spacer
E-mail middletonw@livemail.uthscsa.edu
Author William Middleton
Co-author(s) e-mail
Faculty mentor/Co-author Charles Hermesch, DMD
Faculty mentor/Co-author e-mail HERMESCH@uthscsa.edu
Basic Science Rationale
(Mechanisms that may account for and/or explain the clinical question, i.e. is the answer to the clinical question consistent with basic biological, physical and/or behavioral science principles, laws and research?)
post a rationale
None available
Comments and Evidence-Based Updates on the CAT
post a comment
by Amanda G. Hughart (San Antonio, TX) on 10/03/2014
A PubMed search was conducted in September 2014. According to the literature, Peak torque values within 10% of the target torque was proposed as a clinically suitable torque. The results of a bench top comparative study (Fayaz 2014, PMID: 24688564) proposed combination of steam autoclaving and continued use of torque devices to result in torque values greater than 10% of the target torque thus providing concurrent data with older literature. The 3 articles reviewed/provided in this CAT do not directly compare the effects of aging (or use) of the torque devices to clearly answer the PICO question; however, these articles support the variables leading to inaccuracies of torque values. The articles provided look at differences in accuracy of friction-style vs. spring-style mechanical torque devices (MTLDs) (Vallee/2008), an unspecified mechanical torque wrench after only 5 uses at two different torque values (Santos/2011), and a study looking at three test groups of torque wrenches of between 1000 uses and no uses (new) with subsequent steam sterilization cycles which found only a slight decrease in torque values of used devices (Cehreli/2004). Although a newer study clearly demonstrates that aging (use) as an independent factor affects the accuracy of F-S MTLDs (Saboury/2013, PMID: 23724202), it is stated that the number of uses producing wear, is probably not the major factor of inaccurate torque delivery. The literature suggests that the accuracy of MTLDs were dependent not only on the wrench style, but also on the manufacturer, sterilization cycles, and device calibration and maintenance (Fayaz/2014). The bottom line is, regardless of initial accuracy, it appears that all MTLDs offer less torque values after varied continual use as compared to its new state and a factory calibration and maintenance protocol is necessary to assume clinical accuracy.

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