Dr. S. asks:
I have been using the ‘break open’ torque wrenches to torque down my abutment screws. Recently I noticed that some of the torque wrenches seem to be sticking and are possibly not opening up when they reach the desired torque level. How long are these torque wrenches good for and when should they be replaced? Can they be returned to the manufacturer for re-calibration? What is the most accurate and reliable torque wrench?
Break Open Torque Wrenches Seem to Be Sticking?
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Break open torque wrenches require re-calibration every 100 autoclave cycles. They should be autoclaved in the break open position. Look into the wrench sold by Thommen Medical. They offer a one piece torque wrench cut out of a solid piece of titanium that can be used a a surgical ratched as well and never needs calibration. Good luck.
Break open torque wrenches are popular and sold by several major manufacturers but I feel that they shouldn’t be used. They require careful maintenance and you are trusting that it “breaks” when the correct force is achieved. After having two implants that had been in place for over 6 months “spin” while torquing the abutment, I switched to the “tear drop” style torque wrench. This type of torque wrench has a scale showing the approximate force being used and will prevent over-torquing. You also don’t need separate torque wrenches for different systems requiring different torque values either.
Along with the Thommen Medical wrench comes a latch adapter that makes it universal. All you will need is thye latch screwdriver from most other companies. On top of that, the price is excellent and there is no parts to disassemble and clean. The mono torque is a truly incredible unit.
I was told by our rep from Lifecore that they recommend autoclaving the torque wrench in the “broken” position. We have done so for the past year, and do not have the sticky problem, and last much longer.
Dr S.
Best I can tell, the lubricants are turning into “shellac” in the sterization process and sticking the moving parts to one another.
I usually break the wrenchs and unbreak them a couple of times, before using.
I don’t see how sterilizing in the broken position remedies the lubricant harding during the cycling, except you have to move it to use it, thus guarenteeing it is not stuck—it still may not be moving freely.
I move it back and force till it seems to move freely.
I wonder if a Statum Sterilizer designed for handpieces might not be the best place to sterilize the torque wenches.
Our colleagues are making great suggestions about alternatives to the torque wrenchs we have. Until I can reoutfit I have choosen these methods I mention to work with what I have.
I also wonder if there is a simple inexpensive testing devise that could be used to check the actual torque
readout.
I have seen recommendations vary enough that I feel my tactile sense helps me to know when I have tightened enough. I have to error on the side of not overtightening intrinsically with my big ole hands.
R. Neff
Break open wrenches….Ewwwww. I stopped using them, they can stick. Also, yes, sterilize them in the open position, they can pretty much remove an implant if you are not careful. Look for a better option. As for simple and inexpensive device to test the torque….not really.
The manual torque wrenches have many kind of problems like corrosion ( moisture) and they did not applied target or nominal torque . Normally the applied torques are below the target value. Insufficient tightening of implants screws can lead to their loosening which can cause pre-load failure with damage to prosthesis and fixture joints. The clinicians have applied torque all the time with different ways and they have know the importance of calibrateds torques devices using. The eletronic torque machines must have to be re-calibration but who knowns when. The manual devices are inconstant to apply clinical torque
Zimmer recommends that you recalibrate the wrench, but 1) they will not do it, 2) they will refer you to a company that will recalibrate it – but the cost is almost as much as a new wrench! It’s not hard to do – it only takes a Torx driver to make the adjustment – but you need a gauge to determine the amount of torque being applied. One of the manufacturer’s should come up with a simple testing device to measure the amount of torque being applied before the wrench breaks open.
99% of the torque wrenches on the market work on a metal spring mechanism. After some time and some sterilization cycles, calibration is lost, sometimes pretty fast….
The most reliable mechanism so far is “metal beam deformation”, and transmitting the info with jewels and ruby gears. Torque is readable on the back on the wrench. The gauge shows torque from 10 to 50Ncm.
That is the Torque Lock wrench, from Intra-Lock.
Torque wrench can be tested by devices like a Tonichi Guauge(TG), but how do we know if this device is calibrited too ? If TG is , for how long ? See my first commnt ( July , 2 , 2008 )
Guys here’s the deal, get the wrench that helps you sleep at night, have weekends uninturrupted and allows for call free vacations…buy the Thommen Mono-torque wrench…nuff said!
Those of you that recommended the Thommen mono-torque: could you please elaborate regarding the adapter. I bought the wrench and their insertion device but other (3i, Nobel, Zimmer, Bio-H etc ) do not fit into the insertion device or the wrench itself. Thanks