Cement-Retained Implants Crowns and Bridges: Best designs to help repairs?

I switched to cement retained implant crowns and bridges for three reasons. First of all, it is more like conventional crown and bridge on natural teeth. Second, it is a lot easier than screw retention. Third, my patients would not accept the diminished aesthetics of a screw hole filled with composite. But, now what I have been finding is that when I need to repair the crowns and bridges, I need to drill through the occlusal or lingual and find the abutment screw channel which can be difficult. I have seen now three new design techniques for making this easier.

One is to design the implant crown so that the screw hole is not covered with metal. In other words when the crown metal framework is cast there is an open channel in the metal framework leading to the abutment screw. The second technique is to use a CBVT scan to record the position of the abutment screw channel. The third is to have the technician make a pin hole through the occlusal or lingual and fill the coronal portion with composite that blends in with the porcelain but fill the cervical portion with a brightly colored composite to make it easier to follow the pin hole channel to the abutment screw.

Are any of you using these technqiues and what has been you experience? Do you have other techniques to recommend?

7 Comments on Cement-Retained Implants Crowns and Bridges: Best designs to help repairs?

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Sb oms
4/14/2013
What's difficult about a screw retained crown? It's the simplest design, less pieces, no cement, and completely retrievable. If you find yourself tearing off your cement retained crowns for repair, you shouldn't have used cement retained crowns in the first place. It's really not that much of an esthetic compromise in the posterior. The access hole can be discuised nicely these days. I'm just confused at your question.
CRS
4/14/2013
Check out previous question on cemented crowns, good discussion!
Dr. Trevor
4/16/2013
"You are doing it wrong" is the first thought that comes to mind. The case I did today, for example, was extraction and immediate placement of #18. After placing the implant (and before suturing) I took an open tray impression with medium body material. I will send that impression to the lab and they will fabricate the final PFM screw retained crown on a UCLA abutment. In three months, I will make a mid-crestal incision, expose the implant, screw the implant in place, cover the hole, place two resorbable sutures and that's it. Restoring that implant is significantly easier than traditional crown and bridge. No cord, no worry about margins, no provisional, just make sure that the fixture mount is stable in the impression, and skip the rest of the nonsense. You can restore implants however you like, but I reject the premise that it is an easier process. If my doctor explained to me how easy and affordable it is to repair fractured porcelain on a screw retained crown, I would never consider having it cemented.
Mike Heads
4/17/2013
Does your patient want the best or second best type of restoration.For a single crown I personally in my mouth would put up with a possible VERY slight drop in aesthetics if it was a posterior tooth where the screw access hole is on the occlusal surface, to have a far superior crown. You need to take control of what you deliver to your patients as YOU know what is best for them and it may also help you in retrevability if any problems arise in the future.
Scott barr
4/17/2013
Thanks for your comments about screw retained over cemented crowns. I just had to cut off a new crown because the contact was open and packing food so I had to redo it all over. I also had a crown come off the abutment because it was too short of an abutment height and so I went to screw retained afterwards. I think the comments I read made me realize , wow, screw it in and you can avoid the separate abutment cost as well and a fixture level impression and you are done. Nice wake up call! Thanks
sharon
4/17/2013
Hi there..great topic..has anyone tried any all zirconia milled screw retained crowns or used the Astra system for making screw retained bridges more accurately for a passive fit? Thank you!!
Mike Dargenio
4/24/2013
I'm now having second thoughts about cement retained bridges! What do you think I should get for my case! I have 4 posterior bridges that are implant supported the dr said that cement retained are stronger! Is this true or was she just saying this to make it easier for her not to use screw retained. I also have small teeth does that make a difference ? Thanks mike

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