Torquing Down Implant: How Much Force is Really Needed?

Dr. P asks:
Our protocol for torquing down dental implant fixtures is to go to 30Ncm. Many of our cases require primary stabilization for immediate temporization. But I am wondering if torquing to this level can produce compression necrosis. Is it really necessary to apply this much torquing force to the implant? Can we use less torquing force if we do not require primary stability for immediate temporization? Have any of you experienced compression necrosis and if so, at what torque levels?

21 thoughts on “Torquing Down Implant: How Much Force is Really Needed?

  1. Here is the information I have:

    40+ Ncm with FMT (Fixture mount transfer likw with Zimmer and Implant Direct)- time to remove FMT and use the Bone Tap.

    62 Ncm – FMT’s hex can fail due to exceeding of component capabilities.

    35 – 60 Ncm – Initial stabilization torque for Immediate Load qualification.

    60+ – 80 Ncm – Possible pressure necrosis (over compression of bone).

    Anybody who agree or disagree?

  2. I think that you are referring to the placement of the implant into the osteotomy site. I have found tht the wider diameter implants do not follow the 35-45 NCM prottocol and thet torque wrench breaks before the implant is down. Secondly, you must know what type titanium you are using. Nobel is Pure Titanium and I have snapped or distorted too many 3.5 implants trying to get the cam to face buccal. It is a gut wrenching feeling. If you are using grade 23 or grade 5 titanium you can push the limits slightly but be careful because the Nobel 3.5, even at grade 23( Implant Direct) can fracture if you get too agressive. Some implant companies like Zimmer and the new Revois do not even have a torque changer on the wrench.
    For the abutment I strictly follow the requirements after breaking a screw inside the implant. I guess it is a good thing to learn the hard way but it is better to learn though others mistakes. I hope this helps.

  3. I agree with Dr. Saad.
    I usaully only torque my temps up to 20 Ncm, because I dont intend the screw to get “cold welded”to the implant, I just want it to stay for the healing period (without any contact or under no pressure)and also to be able to retrieve it in one easy motion.
    cheers

  4. There is no evidence that greater torquing equals greater success. According to the literature an implant only need be finger tight (not spinning in the osteotomy) for integration to occur. IF you look at reverse torque studies you will see that the implant loosens slightly from weeks 1 thru 4, retightens to the original toque by week 6, then continues to increase in integration for 18 months (roberts and others). The only reason for needing primary stability of 30-35ncm is for immediate loading. I have placed hundreds (perhaps thousands – whose counting)of implants at 12ncm thru 20ncm with no increase in failure rates.

  5. I basically agree with Saad, with the major concern of not over torquing which can result in implant breakage or deformation. The problem with the numbers is that they are empirical with no good studies to back them up. The other problem is that the initial torque of 30 -32 ncm which you tighten the abutment screw to, decreases within 15 to 30 minutes to about 22 ncm. You should retighten the screw 15 minutes after the initial tightening and then, if possible, retighten again after two weeks. Additionally, you need to be aware that some implant systems have a greater incidence of screw loosening then other systems. Bruce also brought up the the inherent weakness of the nobel internal attachment implants, especially their 3.5 mm implant. If you have access to the nobel system, take a look at the metal thickness at the outer point of the triangular internal well. It is so thin that I personally, would not want something that weak in my mouth. The internal attachment of all implant systems requires more metal removal then the external hex, which prevents the placement of the outer screw form coronally to the top of the implant in the smaller diameter implants.

  6. I have ignored the numbers….after years of doing implants I can torque to finger tight only….when checked with a torque handpiece I have not gained any more tightening…so I actually an getting within the realm of the empirical numbers for the abutment screw and the implant…again it also depends on the bone density

  7. I have had what I suspect is compression necrosis many times. My implant patients have left the office to be restored. The implants are radiographic and clinically sound. I have questioned my patients after implants have failed and many times they mention that the restoring dentist have really cranked on healing caps and the implant abutment. The patients all say it is much more force than I use when placing the healing cap. I can only suspect tension necrosis. I never saw this with cylinder implants, we should all be careful what we wish for. Better is not always Better!!!! Jim Homrighausen DMD

  8. I only hand torque healing screws and collars. I take a PA of the abutment hand torqued, and if OK, torque it to 35 and wait and torque it again and take and impression. I torque it again the same way when seating the abutment for “good” and the crown.Thats it. Not too much. Im conservative. I learned the hard way that when I was placing Zimmer 6mm, I got it down and then the damn thing was fully seated, 2mm above where I wanted it. I was in D1-2 bone and didnt tap the osteotomy. I didnt think the crestal bone was that unforgiving, but I couldnt get it out even with the torque wrench, so it stayed and its fine. I wasnt about to torque that heck out of it and risk breaking the screw. the tissue was thick and it worked out OK, just a little unnerving. But the microgap is certainly highwater! B

  9. Dr Homrighausen,
    Tension necrosis? That doesn’t seem reasonable. Maybe there are other factors. I assume it’s not the same restoring dentist each time. It’s unlikely that several restoring dentists are grossly over torquing the healing caps and abutments. Even if they were over torqued, I have a hard time believing that this could cause a failed implant, broken screw yes. What Ncm are you achieving on placement?

  10. I have seen this kind of problems when I took over the pratice. The restoring dentist didn’t follow the protocols for torquing the abutment for good, because he was affraid of overtightning them and screw them by handforce. After several a few years in place the screws get loose a little bit but to less to be noticed by the patient and giving friction to the screws resulting in killing the srew by frictionmotion

  11. I have started doing something that makes sense to me…..so watch out. I do not reverse torque an implant to see if stable. When I place the abutment, I hold the abutment with a hemostat and then torque the screw in to the “recommended” number confirmed by a torque wench. The screws do not loosen and I do not feel uncomfortable about placing to much torque on the implant it self.
    Now before I get my “head” handed to me…..everyone wants to know if the implant is intergrated. Remember the noble device of the striking of the implant. I am sure someone will tell me that the “noise” of hitting an implant is stupid but……….
    I just do not like putting torque on the implant when placing the abutment…..

  12. I agree with Jeffrey…in fact I developed a “Counter Rotational Torque Control Hemostat” available at H and H…Just call them and ask for Dr. Lau’s Implant Abutment hemostats. E-mail me if you can’t find them.

  13. I am NOT a dentist but a patient. 4 weeks ago I had received 2 implants. At 2 weeks I went and had stitches removed and site checked and was told all was healing nicely. One week after this, strong evidence of infection and on my own started taking antibiotic again so has not to experience strong pain before I can get back to dentist. I told my dentist on the 2 week check I thought he was very aggressive in the procedure and he agreed he had been told he was a little rough. Is this what you all are referring to that might cause compression necrosis. Would like reply on my email Thanks

  14. When we began to acomodate the existing literarture for using the immediate provisionalization….we fall in two aspects
    1 Modification of our existing success rate
    2 increasing implant companies earnings

    We show all colleagues single beautiful cases, but not the biggest failures

    The technique need to be done with skilled doctors

    AH

  15. Ms Marian , it would not be good to make opinions on colleagues, more than if we do not know your Diagnosis.
    Go back to your doctor…..soon!

  16. i placed an implant in #30region @ +80 torque, as the bone was D1 and i had not used the bone tap.The implant was hand ratcheted FOR SOME 20 ODD MINUTES WITH REVERSE TORQUING IN BETWEEN.The overlying tissue was very thin too.At 6months postop, 3 threads were visible through the lingual tissue,and considerable bone loss.However imlant was firm and oral hygiene was maintained well by the patient, so i went ahead with the restoration.Its been 18 months since implant placement & 1 yr. since loading, but there has not been any further bone loss or thread exposure.Do i need to worry ..or i can breathe easy? How much time would it take for such an implant to show visible failure if at all?

  17. I had placed an implant in the lower left premolar region after an uneventful extraction and three months post healing. everything was fine till we saw the patient after four months of implant placement ready to initiate the prosthetic work , when we noticed a ginigival swelling near the coronal aspect. radiographically the neck of the implant showed some angular bone loss . the patient is asymptomatic , put on medicines and referred to the periodontal surgeon for management hereafter.
    Is this also a part of compression necrosis and is the management we are planning in line with accepted treatment norms

  18. I have stopped worrying about compression necrosis now because I have been convinced by other learned opinions that it does not really exist. My only concern now is for the integrity of the implant head and tools. I have cranked many implants up to high torque forces (my guess is way over 60Ncm ) without problems but equally I’m just as happy with an implant which has very little insertion torque under the right circumstances.(I always stick strictly to the manufacturers recommendations for abutment screws of course)

  19. i believe there are no such like compression necrosis, the one that fabric care about the max torque its only the breakage of the internal hex. but for my opinion why do you use lots of power if you can used 35-45 ncm

  20. Just out of curiousity, these words, pressure/compression necrosis never pop up in the days of the Branemark standard implant. Using the Branemark then, there were no such thing called insertion torque, all implants were placed in with just a normal wrench, there were no troque wrenches then, but implants still works. Who is the guy or which is the company who starts to talk about pressure/compression necrosis? Can explain why it works last time and not now? Curiousity kills the cat.

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