Introduction:
While literature demonstrates that the optimum accuracy for final
impressions is obtained with the custom trays, the use of stock trays for silicone impressions appears to be popular if the proper impression technique was used.
Purpo
se:
This in vitro study was done to evaluate the linear dimensional stability of impression made in stock trays and custom trays with different techniques, using poly vinyl siloxane as an impression material.
Materials and methods:
Three different impression techniques was done as follows:
1- Putty wash 1- step technique using stock tray
2- Putty wash 2- step technique using stock tray
3- 1-step technique using custom tray
For each technique, fifteen impressions of a maxillary partial edenulous metal master model were made and then poured. The accuracy was assessed by measuring five dimensions on stone casts poured from impressions of the master model, then these measurments was compared with the measurments of the linear dimensions of the master model.
Results:
Although the first technique was the most accurate, the statistical analysis showed statistically insignificant difference among the three different impression techniques for the stability of the linear dimensions.
Conclusion :
Making custom tray is time consuming and costly; therefore putty wash 1-step technique in adapted stock trays can be used as an alternative to provide accurate impressions, as obtained from custom trays .
