Nobel Active abutment loose, but screw tight?

Nobel Active 4.3mm x 11.5mm implant which has good osseointegration. The screw retained abutment snappy 5.5 conical connection 1.5mm RP was used and a cement retained crown was constructed due to the angulation of the implant. I now have looseness/movement of the crown/abutment even though I have the screw tight to 35Ncm. Any thoughts? Could there be a little cement from crown cementation impeding complete abutment seating. Though I tightened the screw to 35Ncm and radiographed to check abutment seating at the impression stage. I’m stumped!! What to do next??

Recent X-Ray
Recent X-Ray


17 thoughts on “Nobel Active abutment loose, but screw tight?

    • Steve says:

      I agree Aaron,

      This is a common problem with loosened screws.
      Take it apart, screw back the loosened screw and remake the crown…

      Good luck!

      (0)
  1. ttmillerjr says:

    The screw has broken or come loose. Did you use a new screw at the seating appointment? Carefully drill through the crown to access the screw, this will probably be through the buccal, it sounds like. New impression and re-use the crown you removed for the temp. When you tighten the new screw next time, have the patient chew on some gauze after your initial tightening, then come back and torque it a second time. Just one of those things that happens sometimes.

    (0)
  2. Alejandro Berg says:

    Hi, Most likely you have got a loose/broken screw, so you will have to remove everything and start over, remember to do a good interproximal check specially in the mesial due to the angulation of the implant.
    Less possible but still a chance that the implant is fractured, that normally happens at the graft /bone level, lets hope not.
    best of luck
    Alex

    (0)
  3. mpedds says:

    What I now do is to torque the abutment to the specified torque. Remember, we are stretching the screw/threads. I wait 2-3 minutes for the screw to relax a bit and check the torque value again. In perhaps 20% of cases remarkably you can still turn that darn screw a little more.

    (0)
  4. CPB says:

    Seems like abutment screw may need to be relaced. If possible remove crown or access through crown. Either tighten old screw up. Or is probably change the screw. A good thing to do is torque the screw Down. Wait anot 10min and then Tomie again to make sure it is torqued down. Also at end check occlusionake sure you do not have off access occlusion

    Good luck. Chander

    (0)
  5. Willie says:

    In the motor industry the heads on modern engines are torque sensitive, they use the term “stretch bolts” designed to stretch on a small scale. They are not for re-use and my take on loose implant abutment screws is for the same reason. I agree with mpedds, use a new screw as stretching may have taken place. Good luck.
    Willie

    (0)
  6. mwjohnson dds, ms says:

    every now and then the lip of an implant can fracture. Then, even with screw tightening, the internal antirotational hex won’t lock firmly into the implant. When you disassemble the current restoration, look at the lip of the implant under magnification and see if you see a crack. I’ve had implant fracturse not show up on a radiograph and only visible clinically. I’ve also had the internal hexes fracture off so, even with retightening of the screw, it still loosens quickly. My guess is it’s some kind of component failure; screw, abutment hex or implant.

    (0)
  7. Sheldon lerner says:

    Hi
    I believe the original poster said the abutment is loose, but the screw is tight.

    Under those circumstances it is possible that the abutment was on slight angle and did not seat all the into the hex slots of the implant. This is a known issue with NobelActive™. The abutment will rotate slightly or rock but the screw will still be tight as the head has wedged into the receiver section of the abutment. If the abutment freely spins or is quite loose the other possibilities below are more likely.

    A more common possibility is that the screw thread section inside the implant is narrowed secondary to debris and the male screw itself is now wedged into the implant female thread and is not going down all the way. The abutment is loose but the screw is tight.

    The last possibility I can think of is that the screw has cross threaded going down and is wedged in place before going down all the way to tighten up the abutment. Again the screw will be tight and the abutment loose.

    Those are the common causes. Somehow the screw must be removed and the implant thread shaft checked for damage. Sometimes the implant has to be rethreaded…..
    Good Luck
    Sheldon

    (0)
  8. joe nolan says:

    any possibility that the abutment has somehow cracked so it feels loose yet the screw is tight?
    I am not sure how one could be 100% sure that the screw actually is fully tight until you have a look……I have had issue with NB screws loosening in the past ….
    could be a simple enough task to lift the crown off, remove the plug over the screw , and retighten…
    Hopefully , the crown is held on by a weak cement and shouldn’t get damaged…course, these issues are a great advert for screwed in crowns 🙂

    (0)
  9. Ken says:

    Facing exactly the same problem,I carefully drilled the crown to remove abutment screw, the screw looked unharmed so i just torqued it back,I tried to remove the abutment and crown assembly after removing the abutment screw but it just rotates, does’nt come off. 3 days later the crown is again rotating.

    (0)
  10. Ralph Alman says:

    I have seen this type of problem before. The comments regarding needing a new screw are appropriate, and the observation that there is likely a component failure is spot on. When a small diameter implant (less than 4.7mm) is placed in a molar site, there is a greater likelihood of bone loss or component failure. Here we see bone loss around this mesioangularly, distally placed implant. There are long spans of overhanging, unsupported abutment and crown. Given the very heavy angular forces put on the screw and implant fixture (i.e., off axis forces), the bone loss, abutment loosening and suspected fixture failure are not really a surprise. I agree that removing the crown and abutment in order to inspect the fixture is a must. If metal cracking of the implant fixture is observed, then the current restorative solution in #19 site is inadequate. Remove the fixture, consider grafting the site to be sure a larger implant can be placed in an ideal 3D position and restore again. Hope this may be of help.

    (0)
  11. Ralph Alman says:

    As a quick follow up to my last comment, the anti-rotation elements in the implant/abutment interface need to be evaluated. They may be rounded, or some of the threads in the implant or abutment may also be stripped. I still think it is a problem related to excessive forces on a small fixture, inadvertent angulation and distal placement in a heavy force area.

    (0)
  12. tony says:

    I’m seeing similar problems with Nobel Active and am beginning to doubt the integrity go the connection. I like using the implant, but I’m interested to know how common the problem is.

    (0)
  13. G says:

    Nobel active prosthetic screws should be torque to 15NCm.
    35 is far too high for that system, so it should not be a surprise
    that the screw broke. It’s important to know the systems you
    are working with. You have to decide if it is worth monitoring the
    bone loss and keeping the implant (poss smooth out exposed
    thread) vs removing the implant and starting the case again. Good
    luck!

    (0)
  14. g says:

    Sorry for the incorrect info above. Believe it or not the Nobel rep new to my area was giving me incorrect information on the RP torque value. Fortunately, I had not completed the case yet. Hopefully, he was not giving out incorrect info to others. I avoid using Nobel as much as possible. I’ve only came across an Active implant from another surgeon. Thanks.

    (0)
  15. Dean Fogal says:

    Hi. I don’t know if this question makes any sense. Can the screws on temporary implant crowns be tightened too much? I’m in a program where the temporaries have gone in and out many many times for adjustments. When they finally were in and I could go home with them, 2 of 3 of them broke within a couple of days while eating a vegie sandwich. Strange because I’ve had impant temporary crowns before that lasted for several years. They wore down but didn’t fracture. Could be the materials?

    (0)

Comments are closed.

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