ABUTMENT LEVEL IMPRESSION
Distortion
There are two options to take a abutment level impression. The first technique
does not involve any hardware
Collapsed tissue
parts and is just an impression over the already installed
abutment, equivalent to a regular impression for any cementable restoration.
This technique should only be considered as a last resort because it produces consistently poor results.
Before taking a impression directly over an abutment it is best to place a cotton
pellet in the screw access hole and then fill the access hole with composite. To get a more predictable result it is more advantageous to remove the abutment and take a
direct or
indirect impression.
Impression coping
Some implant systems are especially designed to take an impression over the
already installed abutment. Utilizing appropriate manufacturers plastic impression copings.
Impressions taken with applicable hardware will result in a far superior final restoration.
Identify implant brand, (e.g. Straumann® Solid Abutment, Nobel Snappy, Nobel Easy Abutment, Biomet 3i™ Provide® Abutment a.o.), implant diameter
and abutment height installed.
Order appropriate impression coping from the implant manufacturer.
Seated coping
After removal of any comfort caps or temporaries press the pertinent plastic coping on to
the abutment, lining up and engaging the anti-rotational features pre-machined
in to the abutment and the plastic coping. Since the
plastic copings are not radiopaque it is unnecessary
to take an x-ray for verification purposes. Load full arch tray and take impression
with a polyvinylsiloxane (AFFINIS®PRECIOUS by
coltene®,
Aquasil Ultra by Dentsply) impression material because this will
result in the greatest accuracy, over the impression coping assembly.
After the impression material has set, remove the impression from the patient. The plastic coping should be embedded
in the impression material and not be removed from the impression.
Do not remove the abutment after impression taking. Impression trouble
shooting guide.
Good impression
Should the abutment need reduction in case of clearance
issues, reduce the abutment after impression taking if absolutely necessary
and only as minimally as possible. Have the laboratory reduce the analog on the model as needed and furnish a reduction
coping with the final restoration. Send full arch opposing and bite along with the abutment level impression
to the laboratory.