Thirty percent of conventional impressions received by laboratories are inadequate, according to respondents to LMT’s State of the Industry 2010 Survey. Here, manufacturers offer impression-taking tips:
1
Seat impression tray with a slow, steady, vertical seating motion to allow for blending of tray/wash materials.
3M ESPE
2
To reduce voids, use a stirring motion while syringing and keep the syringe tip immersed to avoid trapping air.
3M ESPE
3
3M ESPE
4
To ensure dimensional stability, The impression must be placed in Ziploc bag no more than 120 hours after washing, rinsing and removing excess water.
American Tooth Industries
5
If it’s necessary to delay the pouring of the model, wrap a wet towel around the impression and store it in a plastic or sealed container.
Bosworth Co.
6
Always keep the material in front of and ahead of the syringe tip, and only push the material forward. Don’t lift or pick up the tip while pushing the material around the margin.
GC America
7
Make Sure the tray is adequate enough to allow 2mm of impression material between the tray walls and the teeth.
GC America
8
GC America
9
Don’t allow the material to slump or drip into the oral cavity.
Kettenbach LP
10
Kettenbach LP
11
To avoid pulls and voids, submerse the intraoral tip into the material until you finish syringing around the preparation.
Kettenbach LP
12
Use the correct type of double-bite impression trays to prevent distortion.
L.A.K. Enterprises, Inc.
13
Use a dual-phase technique for better accuracy.
L.A.K. Enterprises, Inc.
14
Use a double cord retraction technique to obtain a better impression.
L.A.K. Enterprises, Inc.
15
If your impression material fails to set around the prep, check to see if the retraction cord contains sulfates (ferric subsulfate or aluminium sulfate), both inhibit the set of PVS materials.
Parkell, Inc.
16
If you are using wash and tray materials from different manufacturers for single-step impressions, check the set times of both and leave the impression in the mouth as long as is needed for the slower-setting material to fully set.
Parkell, Inc.
17
When taking a second wash impression inside a previously taken impression, relieve the contact areas of the first impression prior to taking the wash impression. This minimizes the possibility of tight contacts in your final restoration.
Parkell, Inc.