Impressions for Multiple Implants: Best to Splint all Transfer Copings Together with Resin?

Even if you connect all the impression copings with pattern resin you run the significant risk of deformation in the final casting of the eight units or during ceramic application (with repeated firing of the case). IMHO you are better to take your fixture level impressions (with or without resin as i do not think it will make a difference) and designing the final case for a "post ceramic solder" of the interproximal joints. this has to be discussed with the lab prior to their wax-up stage as the design of the metal work as to be alter to accomidate the use of a post solder technique. this is by far the most accurate method to fabricate any type of multi-unit splinted prosthesis. Dr Dwayne Karateew DDS Dip Perio Dip Prosth

I've tried that once. Didn't like it. Transfers come splinted from the lab. You spend time sectioning them, then splinting them together. When implants are angulated differently, I suppose, paths of transfer's removal are slightly different and that leaves room for distortion. I am certain a-silicone impression materials are good enough on there own for a precise impression. I recently discovered there is a lab procedure "electric-sparkling corrosion", when abutments and metal work are connected to electrodes. During contact everything that prevents metal work from proper fit is burned, so that passive and precise sitting is achieved. Never tried this,but look forward to.

Tie a piece of floss between the impression copings, then add the acrylic. Using this technique, you need to wait until the acrylic is fully set before adding the last bit to lute the section together. Alternatively, you can use a self cure composite resin and let is harden chemically. We have had good success with the latter technique. Remember to use hexless impression copings or abutments for the impression, otherwise, you will not be able to remove the impression, as the divergent hexes will engage the implants. We have overcome the distortion issue experimenting with the top of the line investment materials, burnout oven, and vacuum casting machine. It works, but only after much trial and error. We have precision fits. Of course, no fit is perfect, due to a variety of factors, but the casting will definitely fit passively to the master cast. We still do a verification try in during our jaw relations phase. Our exact sequence, temperatures, and equipment are the result of much research and a lot of trial and error.

Splint the copings together with resin as you described--sectioning and luting together. Let each section cure before going on to the next. Make it thick enough to be rock solid. Before impressing check it for a passive and perfect fit. If you do this you will have a perfect impression of the implant positions. The luted copings also can be used as a verification jig. Your lab should be able to give you a casting that fits--be sure they use machined abutments. Many labs cut costs by purchasing plastic abutments and casting them with the wax up. This is where imperfect fit is a problem that solder relations can't solve. I've learned a lot from being in the ICOI and use of machined components is one of necessary steps. Wish you the best.

Dr. Karateew is correct it does you no good to get an accurate splinted transfer if you use a cast type of restoration withot recorrecting it for casting warpage. I feel that any casting that size should not be done. What if the patient chips the porcalain? Very expensive to replace!!! There is a method where a milled bridge is created and desinged to take cementable porcalain crowns on each abutment/pontic. This way if any porcalian fractures all you do is remove the offending crown and take an impreesion and the lab makes a new single crown. This method is used with the duralay splint impression technique. Email me if you want more info. mmcross@comcast.net

If you have an accurate impression it is up to your lab to give you a perfectly fitting casting. If my castings have any distortion I will section and solder before returning it. Tell your lab your impression accuracy has been verified and you expect it to fit. It is up to you to take the necessary time to get a perfect impression. It is not up to you to make the casting fit! The above technique may be great if you are doing porcelain but you may be doing an acrylic fix/detachable in which an accurate casting will be fine or you may chose milled titanium which is lighter.

By using an open tray system with a special tray, and using a polyether e.g. Impregum (which I think is harder the silicones) and allowing it to set for a minimum of 6 minutes you should have no problem with distortion. By using a non-hex morse taper connection the transfer posts will come out of the implants easily enough even with some divergence. As Dr Huels says by using titanium framework and light cured composite (e.g. Gradia) you should get no ditortion of the framework. you can also add to it should small sections chip off later on. Aesthetically, no, it's not as good as porcelain but could help in this situation.

Do yourself a favor and take the extra time and splint the impression posts together with GC Resin, there are 172 distortion factors when making a metal framework, everything from impression material to investment to casting etc. Minimize the distortion and splint the impression posts. Make sure that you can access each post once the PE impression material is in place and in the mouth, if you lose the screws in the impression material it can be laborious to find each one, to unscrew it and remove the impression. Draw of course can be an issue, but with nobel impression posts, they don't go too far into the implant so you should be fine. Using a lab who deals with large implant prosthodontic cases is critical, because they know how to minimize distortion of the casting of the framework and also application of porcelain. Ultimately you have to design the case and design it so you can retrieve it if necessary and minimize porcelain fx with proper occlusion. visit trustimplants.com to get some ideas on case design. An implant technician I would recommend is from Loma Linda University Implant Center. Gary Hill 909.307.0770 he does lots of these types of cases. Good luck, do one right the first time and they will get easier and easier.

I splint the impression posts with floss(Notwaxed) and resin every single time when it is more than 3implants.Open tray technique works well .you could use tray adhesive on resin ,so it does not get detached from impression material.Also resin need not be too thick,make sure resin is not stuck in any undercut. Remember to expose all screws and loosen them before taking out the impression.You can do it.Good luck.

i am looking for an expert advise about,whats the best protocol while restoring 2 or 3 implants,should we connect them or keep them separate,for example in case of restoring #35/36 and 37 ,is it advisable to splint all or separate all or keep #35separate and splint #36+#37.thx

Definitly splint them together, as this will give the implants a mutual support and will harmonize the occlusal forces on it.