Technique for Spacer Adaptation and Custom Tray Fabrication in Impression Making for Fixed Prosthodontics.

The objective is to minimize the inaccuracies in two-step impressions by homogenizing the polymerization shrinkage of elastomeric impression material in fixed prosthesis fabrication. The objective is accomplished by the technique of spacer adaptation and custom tray fabrication for two-step impressions. The technique makes the use of two vacuum-adapted spacers, selected based on the viscosity of elastomeric impression, and a vacuum-adapted custom tray. The procedure of using the specially fabricated custom tray for impression making is also presented. Consistent thickness of the two different viscosities of impression material is maintained due to vacuum adaptation of the spacers. This homogenizes the polymerization shrinkage of the elastomeric material in different regions of impression, as uniform space is occupied by the material in the space created by the spacer. The procedure of vacuum adaption of the tray material also limits the dimensional change of the tray. The technique minimizes the inaccuracies of impression by homogenizing the polymerization shrinkage of the elastomeric impression, thus promising a well-fitting prosthesis.