Technique for making Implant Level Impressions on Slightly Malaligned Implant Fixtures: Anybody Try This?
Anon. asks:
I read an article in the current issue of JOMI on the Accuracy of Different Impression Techniques for Internal-Connection Implants which described a technique for making implant level impressions on slightly malaligned implant fixtures. The study found that if you have impression copings that fit into an internal connection, you will have less chance of distortion if you slightly round off some of the sharp line angles on the impression copings. This allows you to pull them out of the implants with less force than if all the line angles were engaged. Has anybody tried this?
2 Comments on Technique for making Implant Level Impressions on Slightly Malaligned Implant Fixtures: Anybody Try This?
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Alejandro Berg
10/27/2009
If you are concerned with deforming the impression material when pulling.... use an open tray technique and problem solved, no pulling what so ever, the coping will come out with the impression tray.
Dont round the coping they have sharp angles to avoid rotation, and the purpose will be defeated if you do that. If still concerned change to a heavier or more rigid vps or try a siloxaneter that is stiffer.
best of luck
Powers
10/27/2009
Dido on Berg's comment but think about this...with internal hexed implants that are mod-severely misaligned, you will still get some distortion even when using open tray. The hex connection on an internal implant is much longer than that of an external hexed implant. This long hex length if divergent with other implants or the path of draw will deform the impression material when pulling the tray either open or closed. This is one of the very few advantages of external hexed implants in cases of misalignment problems. External hex is so short it is easily dislodged from the implant when pulling the impression even if divergent. I still always take open try impressions, it is simply more accurate.
