PVS Impressions Good PVS impressions are essential to the lab scanning process. In this diagram you will find the main points to be captured in a good PVS impression. Such attention to this detail enables the scanning lab and the manufacturing lab to produce precision fit aligners. 1- Be sure that the patients midline matches the midline of the impression tray 2- Note the presence of the detail of the anatomy of the teeth as well as the gingival margin. No voids or bubbles should be present. 3- Tooth anatomy such as the cusps and ridges should also be captured in a good PVS impression.
2-step Impressions PVS impressions can be taken with the 2step technique or 1 step. A 2-Step technique will provide information to the clinician that will assist in deciding if the impression should be retaken or not. 2Step impressions also provide increased stability and accuracy. This is the recommended technique although 1-step impressions are acceptable as long as they are accurate.
MIDLINE
4- All palatal, lingual and vestibular regions must be captured in a workable PVS impression.