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.