Fracture on implant supported cantilever bridge: any thoughts?

This is an implant supported cantilever bridge that was placed about 20 years ago. This is in the area #19-21 (21 is the cantilevered pontic). The patient’s chief complaint was a loose bridge. The first PA shows the bridge 3 days before the rest of it fractured. I’m not sure why the cantilever was used here instead of an implant in #21 site as there is ample bone. What is this type of fixture called with no identifiable threads internally? Were the abutments in fact cemented into the implant? I’m debating whether to attempt removal of the broken pieces and attempt to restore the existing implants along with an adding an implant in the #21 site. If so should I look for replacement components or create custom cast posts and treat it like crown and bridge? Otherwise I will consider implant removal and start with a clean slate. Any thoughts would be appreciated.



12 Comments on Fracture on implant supported cantilever bridge: any thoughts?

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Dennis Flanagan DDS MSc
8/18/2017
You can retrieve the screw fragment: Flanagan D. J Oral Implantol Management of a Fractured Abutment Screw 2016 Dec 42(6): 508-511
Brian
8/18/2017
They don't look like screws. Are they press fit? cemented?
Neil Zachs
8/18/2017
I agree with Dr. Flanagan. I would definitely try to remove the screw fragment. If it is not wedged, it often times comes out nicely with an ultrasonic tip moving it in a counterclockwise direction. If you can get the screw frag out, I agree....add an implant in 21 and then have all 3 restored. According to Misch, splinting all 3 is a good thing based on distribution of forces, but that is obviously up to you. And if the piece of screw can be removed and you are able to utilize the implant, you may want to graft the coronal of both (prob Bio-Oss) as there is some cupping of the coronal bone probably related to the past odd forces on the implants. Not that grafting implants is very predictable, but definitely worth a try. And you are correct...if screw cannot be removed...then its trephine time followed by graft and replace. Good Luck!!! Neil Zachs Periodontist, Scottsdale, AZ
WJ Starck DDS
8/18/2017
I don't believe those are threaded components, they look press fit to me. I doubt there's any way to retrieve them. One option you might consider that would be more expedient for the patient would be to place a wide platform implant #18 and another in 21, then just cut the old implants off at the crest. I'd probably go screw retained if this patient is a heavy bruxer
WJ Starck DDS
8/18/2017
Hmm on second look it appears like there is a sum total of two internal threads. What a weird design. I doubt the engineer that designed those is still employed lol. I still think I'd go behind and in front with new implants. Anything else and there's a 50-50 chance that something else bad will happen which = unhappy patient. Personally I'm not a big fan of trephining as heat kills, often catastrophically. I like to go with the most predictable route or you could be marrying an ugly problem. And divorces are never pretty 😂
michael
8/18/2017
Biohorizions has a screw removal kit
Brian
8/18/2017
I forget what they are called, but some of the older patients in my practice have these. The abutments are cemented into the implant. But if you have the bridge, you could confirm by separating the bridge from the abutments and looking for a screw head that would engage a torque wrench driver. I don't think you'll find one.
Daniel Nava
8/18/2017
I think these componets are too old. Take out both implants
Elijah Arrington III
8/18/2017
we need to see a BW and some roots on a PA. A pan would be nice (Duhh) option1: cut them (old implants) off subcrestal, so that they will get good bone coverage as they heal over. place new implants for three to four unit bridge at 20 and 18 as suggested above. Be care of 21 premolar its roots are tilted distally. option2: do custom abutments with new 3 unit bridge; make sure there is no occlusion on pontic (#20)-what you were already thinking option3: new implant only on 20: killing #19 implant and make three unit with #18 as pontic ( no occlusion on pontics), with abutments on 20 and 19 implant only. this is the reverse of your current situation; which is ridiculous since you have ample bone behind #19 implant. to save patient money and your self a surgery--remove internal components, place metal post in implants, take pvs with medium and light body, send to lab, fab new abutments, and crowns (same 3 unit bridge with no occlusion on pontic #20) and send to hygiene after cementation :). This is exactly what you would do when making a lab fabricated root canal post and core crown and bridge. Saves time and money. option 4...send the old bridge to the lab have them fabricate new post (welding; solder i.e.) and re-cement the bad boy (old bridge) back in the patient's mouth. that should be less than a grand for the patient. Of course, you still have to take a 330 friction grip bur and remove internal components and take a PVS to be sure that the new welded post fit. Please consider the patients budget and mine since I shared my thoughts please forward any fiduciary appreciation to the address below. ( Just kidding) I wish you well. God Bless.
Junius Gibbons Assistant
8/18/2017
These look like Niznicks old screwvent design. These are not screws but cement retained solid posts with spheroidal midpoint for cement retention Close examination of the implant just before fracturing shows evidence of flowering .....the metallurgy of these old implants is suspect and should not trusted, the alloys used today are much stronger. I would bury them both and place new fixtures mesial and distal which may require a ridge split to get adequate width. Piezo works great for this on the lower arch.
Jason Larkin
8/19/2017
Heavy bite forces after years of wearing other teeth down until bridge started to contact in centric....that is if it was ever a shim stock out in the first place. Then it looks like see saw effect with center implant as fulcrum. Dr. Gerard Cuomo of Boca Raton Fl. has wonderful videos on YouTube about removing broken actress. Tough case doc....best of luck.
gmk
8/19/2017
Those implants seem to be old Screw Vent from the 1980's- early 90's from Paragon. They were offered either with internal thread (as they still are today) or with a cemented connection. If there is a chance to remove the broken stems, that would be using a high speed very small carbide bur and of course using a microscope. I agree that Dr Cuomo from Boca Raton is an expert on doing this kind of very delicate job!

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