Dimensional accuracy of dental casts: Influence of tray material, impression material, and time

Abstract

Accurate casts can be made with either stock trays or custom trays. An impression made from polyether should be poured only once and within 24 hours after impression making, because of the distortion of the material over time. Silicone impression material has better dimensional stability than polyether. .

In Vitro Comparative Evaluation of Different Types of Impression Trays and Impression Materials on the Accuracy of Open Tray Implant Impressions: A Pilot Study

“…One considerate aspect that has not yet been researched in detail is the proper selection of the impression trays for implant impressions for completely edentulous situations [22–27]. The accuracy of the resultant impressions, however, is contingent to the combination of the impression material and tray used.…”

Linear dimensional accuracy of a polyvinyl siloxane of varying viscosities using different impression techniques

“…The main objective in stock tray fabrication is to provide a rigid tray, which provides retention for the impression material 38 . Many studies 2,30,37,39–41 have reported that custom trays provide more accurate dental casts than stock trays, but if stock trays are properly oriented, the impression thickness is uniform, and stock trays can give a better result than custom trays 14 …”

“…One hour after the impressions were set, each of the 40 impressions was treated with a surface‐reducing agent (debubblizer; Prima Dental Products, Mumbai, India) 14 . The impressions were poured with high‐strength dental stone (type IV, Kalrock, batch no.…”

“…The measurements from the master and the stone models were made with the help of a traveling microscope 14,20,31 (micron; Instrument Industries, Hyderabad, India) capable of measuring up to 0.001 mm. The vertical dimensions were measured with a non‐stretchable thread along the surface.…”

“…These viscosities can be used singly or in combination in different impression techniques used in clinical practice 2,11–13 . Although custom trays have been recommended to produce more accurate impressions, stock trays remain popular because they are readily available and easy to use 14 . There is much discussion in the dental literature regarding the effect of the impression technique on the accurate fit of cast restorations.…”