Restoring Full Arch Cases

There are times when multiple dental implants for a full arch fixed prosthesis do not have ideal angulation. The ideal of course would be to have all dental implants in the arch parallel to one path of insertion.

In an atrophic mandible, even with distraction osteogenesis or grafting, the angulation of dental implant fixtures may have to be off an ideal vertical path of placement because of the morphology of bone volume. Does anybody have any recommendations for restoring full arch cases in an atrophic mandible when dental implant alignment is less than ideal?

10 Comments on Restoring Full Arch Cases

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Dr. R Mosery
3/14/2006
I understand that most cases are "Bone Driven", that is ,you place the implant where there's adequate bone. Many times this could be a challenge to restore. Being the restoring dentist as well as the one placing the implants I rarely have this problem because I'm conscious of the end game throughout. The proper planning using radiographic stents with the imaging available and even the cadcam surgical stents would leave much less to chance. There are multiple options with implants placed less than ideal. A.Segment the case more than you planned if suppport allows. B.Use custom abutments. C.Use telescopic copings D.Fabricate a gold bar and an overdenture(this one has to be addressed with the patient from the begining. The last thing you'd want to do is inform the patient they'll be receiving something removable when they've anticipated a fixed restoration.
Mark Adams, DDS, MS
3/14/2006
If angulation of implants precludes a totally screw-retained prosthesis, then I use a combination of copings/screw retention in a hybrid, fixed/detachable prosthesis ('Profile Prosthesis')Pract Periodont Aesthet Dent 1999;11(1):143-151. Tom Peters, CDT of Northshore Dental Lab is very experienced in this prosthesis (800-338-5850)
Ira N. Dickerman, CDT
3/14/2006
When a fixed prosthesis is desired with off angle implants we have made a meso structure or primary bar with tapped retention screws to "bury" bad angulation. This can be designed as a PFM framework or Hybrid Prosthesis. This looks similar to a rigid milled bar patient removable prosthesis. The difference is the patient can't remove it, only the dr can. It has no flanges and is shaped apically like a hybrid prosthesis or PFM Prosthesis depending on the mesial - distal implant location.
Anon
3/14/2006
If implants are not in the correct place for fixe , turn the case to removable or suffer the consequences. Simple stupid.
anton j voitik mdt
3/14/2006
Several issues come to mind: Where are the implants, that is, what is the AP spread - (think what Malo does on 4 implants); What is the vertical and labial/lingual bone dimension in area of implants, ideally, if there is not sufficient width (see discussion of such cases in C. Misch's books)transosseous placement in anterior mandible with a rigid connection to a framework ad modem Branemark has been successful, long lasting and even showed strain-and-stress-driven bone growth in posterior mandibular aspects. I wrote some articles for my lab colleagues some time ago about this. And, yes, planning in 3D definately helps to determine best solutions before surgery. So, call your favorite lab and see what they have to offer. Anton (Tony) J. Voitik at Systemic Technologies LLC, a different kind of lab.
Gary D Kitzis DMD
3/16/2006
Drs. Mosery and Adams and Mr. Dickerman each gave you good advice, and covered the good options. Probably any of them would work well, although I probably would NOT segment the case in an atrophic mandible because as he said, "segment it more if support allows" and it probably doesn't in an atrophic mandible. Don't bury the offending fixture(s). In an atrophic jaw, you probably can't afford to lose the support it will give, despite being off angle, unless it is at a ridiculous angle. Laboratory support will also be helpful in selecting specific options.
Kevin Huff, DDS, FAGD
3/20/2006
If the implants are within 40 degrees of angulation from one another and if the neutral zone will allow for attachment hardware, I would consider a removable denture retained with Zest Locator attachments. It's best to fabricate an ideal denture (you might consider a metal mesh if space allows) and then retrofit the attachments chairside, similar to an "IMTEC Retrofit". This allows you to switch to an "extended range" retentive ring on outlying implants before proceeding with more properly aligned implants. I have found mult-unit Locator overdentures to be very satisfactory to difficult patients. Good luck!
el Greco
3/22/2006
Just a warning from the greek in ozzie land down under. Implant cases fail when more than two implants are used in removable overdentures UNSPLINTED. In an atrophic mandible, start with the simple solution, 2 locator abutments in the canine site implants and healing caps else where, nice and simple. one single axis of rotation without exerting or engaging the others. If you plan to use ALL the implants, they MUST be splinted by a bar and then an overdenture with at least 3 attachments as far apart as possible. If you want fixed, a milled bar laser welded to custom abutments will overcome the undesirable angulations. The path is then free for pfm or coenforced resin like only el Greco knows. Ya Sou
Dr. Fouda
5/22/2007
It's simple, use angled abutments and splint your implants
CM Ceramics
7/11/2007
Depending on the implant system used, will depend on the the stock pieces available. This hydrid fixed-detachable prosthesis is what CM Ceramics specializes in. Basically, it is our focus, as the hybrid cases are how we believe every full arch implant rehabilitation should be for long-term patient maintenance, hygiene, and satisfaction.

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