Try to Remove Abutments But Can’t Find Access Hole: Any Ideas?

A new patient presented with a maxillary bar overdenture that needs to be replaced. The implants were placed about 12 years ago. Firstly, I couldn’t identify this implant and needed some help with that. Also, when the bar was removed (with a 0.48 hex torque wrench) I attempted to remove the abutments that attach the implants and the bar, I could not find an access hole to insert the torque wrench into. I have never seen anything like this as I am not sure how the abutments were torqued down into place. I am not sure if the access hole was filled in with amalgam, but the surface inside of the abutments where a screw access hole should be is smooth and shiny and flat. How these were placed I have no idea. Please help if you can. I had one person say they thought it was Biohorizon but I have no idea. I appreciate any help and any idea what tool can be used to remove these abutments. Thanks so much.

Implant pic #1

Implant pic #2

13 Comments on Try to Remove Abutments But Can’t Find Access Hole: Any Ideas?

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Itawil
3/30/2012
Intra oral photos would help
jim
3/30/2012
Go to the website whatimplantisthis.com but there are some systems where the abutment is torqued with a wrench that fits over the top of the abutment. Not sure if this is the case here but a possibilty. Use the website to identify first!
jim
3/30/2012
it does look like an internal screw now that i looked again....not sure about this one
Dave
3/30/2012
These are older Corevent/Paragon style implants. The abutments are 1-piece, so there is no screw to remove. You'll need the abutment driver - assuming these were torqued into place - to remove them.
Dr. Alex Zavyalov
3/30/2012
.Something is wrong with case description. I’ve never seen “…the abutments that attach the implants and the bar” Abutments cannot be attached directly to the bar. To make a new overdenture it’s not necessary to unscrew the abutments, simply make new crowns with bar and then overdenture.
E. Richard Hughes, DDS, F
3/31/2012
I would contact the prior restorative dentist and ask he/she those questions. Alex, the abutments can be incorporated as part of the bar. The bar can also be cemented to the abutments, if the vertical is adequate.
Dr. Alex Zavyalov
3/31/2012
Agree with you, Richard, if it’s cemented.
K. F. Chow BDS., FDSRCS
4/1/2012
Dave is totally right. These probably are one piece abutments with a screw incorporated. You do not need to remove them. What you need are analogues to place into your impression. They will be fixed then in the models and you can build your bar accurately then together with the screw holes.
peter fairbairn
4/3/2012
Agreed Dave , having used ( in early 90s ) and still occasionally do now use a one piece milled abutment where you rotate the whole abutment into the implant . So to remove grip and rotate anticlockwise , it should have always been the other way as if you need to prep in the mouth the rotational forces of the handpiece used to spin the abutment out. Couple of other things after 12 years the xenograft is still very apparent and the implant in the sinus whilst stable does not have that much new bone supporting it , yet has worked well. Peter
Ed Kusek DDS DABOI FAAID
4/3/2012
This is a microvent implant that has a cemented post. These were done in the late 80's to early 90's. If the posts is removed you will need to tap new thread into the implant. Not sure who makes tapes for this implant anymore. Lab called CalCeram has allot of old parts from allot of implan companies. I wouldn't remove if possible
Dr Samir Nayyar
4/5/2012
Hello Just find the implant from whatimplantisthis and get an analog with abutment. take impression as it is and fabricate a new prosthesis. Don't try to remove the abutment. Have a nice day
Gregori M. Kurtzman, DDS,
5/14/2012
I believe the abutment has not antirotational aspect with the implant and is a one piece and thus does not have a separate screw holding it to the implant and therefore you wont find a hex inside to engage a wrench tip. So you would need to grab the head with a hemostat to rotate it off but the problem is finding replacement parts. They appear to be old Corvent implants and were discontinued many years ago and are discontinued in the mid 1990's. If your planning on remaking the bar then would suggest if you can not fin impression heads that you make some from GC Pattern resin using the screws that held the bar on
Darwin
8/8/2012
These are Micro-Vent 4.5 platform with TSI abutments. They require a .07in./1.77mm hex screw driver to unscrew.

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