Upper Hybrid Frame Design

paulg100 · Feb 16, 2012

Have a case that im doing a Upper hybrid denture on.

The frame will actually be cement retained over the abutments.

Trying to get some ideas for upper bar designs but all i can seem to find at the moment is images for lower bars.

If anyone has some images for uppers then id really appreciate if you could find time to post em here.

Thanks.

droberts · Feb 16, 2012

A cement retained hybrid denture? With denture teeth? I would not recommend cementing that! As for a bar design. Do the denture set-up then fabricate the bar to your set-up. Here it is either done using Ti bar stock and laser assembled, or CadCam.
As mentioned above, would not cement.

Now if you are referring to a bar, with attachments. Normally those are not cemented either. The bar is still fabricated in relation to your set-up. Attachments placed accordingly.

Explain what your wanting, I can find some bar photos.

JohnWilson · Feb 16, 2012

paulg100 said:
Have a case that im doing a Upper hybrid denture on.

The frame will actually be cement retained over the abutments.

Trying to get some ideas for upper bar designs but all i can seem to find at the moment is images for lower bars.

If anyone has some images for uppers then id really appreciate if you could find time to post em here.

Thanks.

Like Danny stated not wise to do this the best option for this type of appliance is with milled 2* taper abutments with galvano copings cemented into a cast supra-structure. The fit on these are amazing and you still have the prosthetic retrievable.

paulg100 · Feb 16, 2012

yep ive already warned the client but its what he wants. The case is a salvage job on a mix of old implants, replacing a similar previous appliance made elsewhere. two fixtures failed (maybe that should indicate something!)

The way the original denture was made, theres no anterior space and its locking the patient into centric so the occlusual issues may be playing a big part in the failures although i understand the patients oral hygiene is extremely poor.

Theres now 3 abutments, one each in the canine region that are osseo ti , then a straumann in 4/5 left premolar region. then the right premolar is a natural abutment, that is having a sub coping over. (the natural abutment was not part of the original bar/frame )

Yep i know many say you shouldnt mix implants and natural abutments, but there seems to be alot of mixed opinion on this with many clinicians reporting good long term results in doing so, although again, it was not my recomendation.

Should of taken a pic of the model to post but im not back in the lab now till monday. Has some crazy ass abutment design, the original lab that worked on this needs shooting!

I Know this is pretty unconventional and the client is aware of the risks. Most of my times ceramics so would of been happier doing it that way, but i think cost is an issue (isnt it always!)

I already have a setup so the milling center has something to ghost to design the bar,which will be milled in TI.

just trying to get some ideas of upper bar design's so i can see how much support/space and retention is needed.

EDIT: Managed to get some pics.

aimg860.imageshack.us_img860_1273_img0006i.jpg

aimg59.imageshack.us_img59_1272_img0009pan.jpg

And yeah its not just the camera angle, that nearest abutment is almost touching the lowers. This is when epoxy resin is worth its weight in gold. Great design eh!

ive already reduced em and made some reduction copings. Imp accuracy has been verified with a jig.

Jo Chen · Feb 16, 2012

Tough one. This should be designed as an overdenture due to the postion of the abutments. Forces will be anteriorly and posteriorly of the abutments much like a teeter totter. A overdenture will distribute the load over a greater area and reduce the teeter totter effect.

Hary · Feb 17, 2012

It should be more like over denture. If the Dr. wants to cement the case.the bar where the pontics are should touch the ridge be covered wraped with acrylic and denture teeth or let the titanium touch the ridge for better hygene, like every one said its to much load on the anterior area. with over denture the life of the existing abutment will be longer.

paulg100 · Feb 17, 2012

Good advice so far, thanks all.

Any one have pics of sample maxilla bars?

nvarras · Feb 17, 2012

I would stay away from a bar and go with free-standing abutments on this because of the position of the implants and the fact that you are opposing natural dentition (for now). ERA, Locator...pick your poison.

rhicks3302 · Feb 17, 2012

Paul, I'm thinking that we're not showing you bar examples because we don't want you to do it that way.I could show you maxillary bar designs but they are all on 6-8 implants. There are so many issues and possible issues here. Not enough implants, poor hygiene, cantilever forces, probable parafunction. Plus the fact that a similarly designed prosthesis has already failed.

I'm not sure locators, or any attachment, would be effective because of their positions. John's idea is the best if you have to do a rigid design but I still don't think there is enough support. I'm sorry that you're in this spot. This is really tough.

JohnWilson · Feb 17, 2012

The biggest issue is ant cantilever. This will be a failure with the design the Dr is requesting.

This case is not a candidate for an implant retained/supported appliance, it should be designed as a implant retained tissue supported appliance.

Write up a good disclaimer if your client insists!

cnhart@me.com · Feb 19, 2012

I'd have to suggest you consider the periodontally compromised lowers. The will act like piano keys. I would try a fixed full acrylic very short term temp to assess - shape, hygiene, loading, etc. I wouldn't commit to anything until a proper diagnosis is established. This is not as bad as it seems. As a prosthodontist, I'd be taking things slowly. How about an opg to check bone levels etc... Diagnosis of actual problems vs estimating problems is expensive. There are no golden rules as you see......