Maxillary Implant-Supported Roundhouse Fixed Partial: How Do I Angle the Implant Fixtures?

You won't. Your parallelism will come from the abutments placed on the implants. You will not be able to have 8 parallell implants in the maxilla. Your lab will create custom abutments which will allow your one-piece framework to draw.

This is easy, just take a fixture level impresson and give the lab an excellent bite registration.

I would use Atlantis abutments if compatible with the implant system you are using. As a matter of fact I would let that help me decide which implant system you choose. Zimmer can also do CAD abutments for their system the same as Atlantis can for Nobel, Biohorizons and several others. You can check out the Atlantis compatibility charts. You will get the most anatomically correct emergence profile for the best possible esthetics and your cement margin will be ideally located just below the tissue at the level you determine. Everything can be milled parallel for ideal path of insertion and proper clearance for you PFM restoration.

Two questions still remain. How do you orient the anterior implant fixtures relative to the posterior implant fixtures? The bone morphology would seem to dictate that the anterior implant fixtures must be angled or flared to the buccal. How do you make an impression of implant fixtures when some are parallel to the plane of occlusion and others are angled -- as in this case.

Dr. J- The anterior implants will be flared in relationship to the posteriors due to the anatomy of the maxilla. As far as impressions go- you would take an implant level impression using an open tray technique. It is the only way to deal with implants which are more than 10 degrees out of synch with eachother.

This sounds like serious redundancy. If you have sufficient bone, 6 implants for a maxilla are adequate to support 12-14 units. This is the "Holy Grail" of implant dentistry. NOTHING IS MORE DIFFICULT EVEN FOR EXPERTS- be very careful. P.S. I would never rely on an implant manufacturer or lab to dictate my plan of treament. Last time I checked it is your name on the entire treatment including the lab.

Why do a roundhouse? It will be very difficult to seat a single unit FPD with 12 units and 8 abutments. Why not place implants in the first molar and first premolar sites and do 3 unit FPDs? Then do an FPD for the anterior segment. Three FPDs should be far easier to seat than a roundhouse.

I aggree with Dr. J. But why so many implants to do a roundhouse. I would be happy with four 13mm to 16mm well placed implants (2 molars and 2 canines). Angulation problems are resolved at the laboratory level if everyone knows what they are doing.

DR. Sylvester, four implants to replace a full arch is not recommended. With all due respect, I would like to know how you can back up such a ludicrous statement. 8 implants is the recommended number for a maxillary full arch recon according to most of the main podium spaekers that one would hear at implant meetings. I for one have not been able to place too many 16 mm implants in the first molar regions. Dr G's positioning of the implants is correct. Instead of a roundhouse. He could do a 6 unit FPD from cuspid to cuspid and then screwed in posterior bridges from first bi to first molar. The anterior bridge provides cross arch stabilization and the custom abutments can compensate for the labial angulation of the implants. I always do closed tray impressions for these cases. I am not a believer in open tray especially when you haven't unscrewed the posterior copings and the patient is dying to get the thing out of her mouth. A good PVS material can work very well with angulated copings.

If you make a fixed prostetic device on is I would place the implant in the same way I would make in that region a small bridge. So I would place the implants in the molar and premolar site perpendicular to the occlusal plane. In the front region I would place the implants as if I would do a single implant placement. I wouldn't tilt the implant to much buccaly, but try to have a 2 mm distance from the buccal plate and to do an extra soft tissue reconstruction to get a good esthetic outcome in this region. Since your implants still will be angulated to each other I make always an open tray impression on implant level and ask the lab for custom abutments. I have heard when you don't want to use this expensive abutments you can also try to use abutments you can customized yourself with a drill in the mouth and then making a impression like you do normal crown/bridgework. I don't have any experience with this technic, since I don't use it. I think you will get more trouble to get a loose fit, which is allready very difficult. But since the loose fit is difficult with a roundhouse, I like to split it in different units to do the fully arch reconstruction. It is also easier when you do have to repair in the worse case senario

Re: DR. Michael Weinberg's above comment... I take it from this you are not a fan of Nobel Biocare's/P.Malo " All-on-4 " concept? I am not sure considering Dr Malo is coming to New Jersey that he would agree it is ludicrous....nor the thousands of patients who are out there living well with 4 implants 10-12 teeth..Have you ever read any data on this concept? Or at least followed a case?

Why listen to anything Nobel Biocare states? Sterility is now even in question I hear - new packaging is said to of been tested but failed...Anyone know whether there is any proof of that?

Re:Sterility & Nobel Biocare...on Implant Direct's website,it has been subject to dye testing and failed according to website data. Whilst on subject is anyone using Implant Direct,if so any thoughts? I am looking in to changing but would like to hear from anyone with good or bad to say...I can read data,just would like to know of whether company supports you well?

Take a fixture level impression with a metal tray and let the lab work it out. It will take too long to prep in the mouth. Save yourself the time and enjoy your family, golf, fishing etc.