Crown 1mm Short of the Margin: Recommendations?

Dr. B. asks:
I cemented a crown on a dental implant abutment using a mixture of Tempbond [Kerr] and Vaseline. Pre-cementation radiograph showed a perfect fit. The post-cementation radiograph showed that the crown was 1mm short of the margin.

I have attempted to remove it and re-cement it but have been unsuccessful. Any recommendations on how to remove it? On the other hand, the occlusion is clinically acceptable, so what would be the danger in leaving it as is?

20 thoughts on “Crown 1mm Short of the Margin: Recommendations?

  1. Well, unless you hacked the top off, I would think that the occlusion would be off a bit. Leaving it short gives bacteria (as well as peas, kernels of corn and other small food items) a chance to populate the area and increase the change of peri-implantitis. My opinion is that you should try to remove it, you wouldn’t leave a regular crown that open. The best way, if you can’t pull the thing off, is to cut it off with copious irrigation. The other thing you can try is a Jolly Rancher (I’m not kidding). After sucking on it for a while, have them bit into the crown. I’ve had patients pull off screw retained restorations that way (now I’m kidding). That being said, I don’t think there is a long term study that looks at the prognosis of improperly seated restorations. If you leave it, I would be interested to find out what would happens

  2. the only problem is bacterial ingrowth which is a serious problem that will increase with time after the cement is dissolved…if there is a 1mm gap you can insert an ultrasound tip in the gap and work on the crown with irrigation, it will come out at the end…

  3. What type of implant is it. You may have a transmucosal implaant or a new platform switch. The second looks like a short margin. Just checking

  4. You should be able to remove a recently inserted crown retained with TB with modifier (Vasaline). A few tricks from a salty old dog. 1. Rinse for 3-5 mins with water as hot as the patient can tolerate.(causes expansion of the crown and weakens the cement cohesivness). Use rubber tipped hemostates with Carborundium dust on the tips. Rock back and forth and the crown will come unseated.
    2. Rinse as above. Use a thick toffelmeyer band in a toff. retainer. Insert it ‘upside down’ from the manner in which you would use it for a Class II amalgam. slip it over the crown with the narrow end of the toffelmeyer bands loop towards the gingivae. tighten retainer and lift coronally leveraging on the retainer. This is my ‘go-to’ technique.
    email me at info@drkarateew.com if you have any questions
    Dwayne Karateew

  5. Dr. DKarateew suggestions are excellent for removing the crown. May I suggest a more predictable way to cement your implant crowns and bridges to avoid the current scenario? Even though you “cut” the Tempbond with vaseline, the viscosity can be problematic, especially with less than 4 degrees of taper and long clinical abutments. My cement of choice is Improv. It still will give you the retrievability you are looking for, the viscosity is perfect and it does not wash out like tempbond will. GJG

  6. Have the patient bite into an Abazaba candy bar firmly and open suddenly. They are great crown removers

  7. One, Don’t use temp bond. It is too thick. The vaseline may mess with the set and the expression of cement.

    If you are really thinking of doing a temporary cement seating use IRM, very thin mix. I prefer permanent cement.

    Two, Removal can be done with a rubber tipped crown remover as suggested.

    Wiggle the crown at the margin as your fulcrum, not along the entire long axis of the implant.

    When all else fails, before I cut, I use serrated pedodontic extraction forceps. This may ruin the crown but so will cutting it off. Carefully place them (jaws) at the cement line entirely on the crown, just above the implant body/ abutment. Mostly squeezing very firmly, with rotation or a little rocking alternating, again using the margin as the fulcrum, patiently, slowly, for a long while if needed. It wiill still be sooner than cutting will take.

    Grasp the alveolus to make sure you are not disturbing the implant body, rocking interprximally, rather than facial lingually is best although it sounds impossible, it can be done when alternated with rotation and a minimum of facial lingual action. Visualize the cement layer you are trying to tear internally or the interface with the crown or abutment.

    The antedoctal sense is that whenever I try to extract a tooth with a crown on it, the crown always comes off first!

    Finally, if you continue to use temporary cement try the lubricant on the surface, crown internal, or abutment not in the mix. I like peanut oil for this followed by copious air.

  8. Jolly Ranchers (supplied by the front office staff) or Abazaba’s are a tasty alternative to the Richwil crown and bridge remover from Almore.

  9. Dear Dr.B,
    If occlusion is fine leave it alone.In future if the cement dissolved the crown will be easier to remove.Do not worry of getting caries on implant.If the patient has good periodontal health and implant is well positioned ,well balanced occlusion you will have great out come.A band of fibrous collar will maintain a passive seal.So do not worry be happy and enjoy dentistry.

  10. It is uncanny how well tempbond works holding a ceramo-metal crown to a titanium abutment.

    If you can get the crown to come off using sticky candy…that is terrific.

    Miltex make a Weinman Crown gripper with serated tips that will hold the crown very well, and at worst, it might scratch the porcelain.

    If the abutment is straight and not angled, the screw can be accessed by drilling a small hole in the occlusal surface, and the crown and abutment will come off together, and can easily be separated by placing it in front of a lab oven for a time to break the cement seal.The crown can be recemented, and the hole closed with GIC or composite. It is now a screw type situation, easily removable.

    An angled abutment will not give direct access to the screw…. go back to the to the sticky stuff.

    Gerald Rudick dds Montreal

    Placing a metal matrix band around the crown, and then tapping it with a spring loaded crown & bridge remover, may damage the threads on the implant,and may also risk extracting the implant.

  11. A crown & bridges remover, named Wam-Key, is very useful in these situations. You need only to drill a small elliptical hole buccally, insert the device, rotate it and it’s done. Then you can repair the crown with composite, since the hole is not in a stress-bearing zone.

  12. The tempobond shoud not be used for temporary cementation of dental implant because it is very flewable and run behind the tissue and you could not perfectly remove it,so always use phosphate cement and permanently fix your crown and u can easily remove the excess material,in case of trouble grind a hole in crown,remove the composite and temporary filling material,open the screw remove the abutment,and leave the headache for dental laboratory,and refit the crown and cement it in the place.
    Best Regards
    Dr.Heshmati
    Postgraduate in Dental Implant

  13. leave it alone, but if the occlusion is too high use a rubber tipped plier to remove it.

  14. I agree with most of the comments re use of various cements
    The methods of removal all also useful

    However the end result is a technical failure

    In my mouth I want this crown removed and remade (I dont want any holes drilled in it ) and I want a good fit
    is this not what every single one of us would want ?

  15. i think the main problem that your crown and abutment is not the cement, but its hold tight metal to metal like bicon concept. and is become worst with tempbond. you can try the tips like other doctors suggests

  16. There is a product made out of a thermal plastic that it heated and the pt. bites into it then after it cools they quickly open and the crown comes off nicely. I assume that the path of insertion is along the same axis. it is called Richwil Crown and bridge remover sold via Almore.
    If you can’t get it off with resonable force just cut it and eat it.

  17. Please leave it alone. Review the patient yearly. If there are no untoward complications, continue to leave it alone. This problem can be classified as one in which the solution will cause more problems than the problem by itself, which may prove not to be too much of a problem if you leave it alone. Nuff said.
    Cheers.

  18. I have a case where I had a crown installed that had no contact with the upper tooth (crown not high enough). This caused malocclusion and problems with my bite and my front teeth have now been damaged due to collisions. The dentist says that the crown is permanent and cannot be removed. He wants to grind down the front teeth to try to relieve the problem. I have been in pain nearly every day and my front teeth are being ruined. Help!

  19. Patti
    if you are describing the case correctly ..
    Your dentist has no idea what he is doing
    See another dentist asap

    the front teeth have not been damaged by the inadequate crown..however
    grinding them to make a poor job fit is ludicrous
    Just have the crown changed ..also sounds as if you may need some crown work on the front teeth

  20. pfm done multiple times still has open distal margin. last attempt with 0.8 mmm gap. the die has been ditched too short has asked the lab to fix it, no luck yet. please help.

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