Comparative evaluation of dimensional accuracy of irreversible hydrocolloid impression material using different types of tray

Irreversible hydrocolloid impression materials are widely used in dentistry due to their low cost and ease of use. To ensure accurate models, it is essential to determine the optimal tray design and material. This article compares the dimensional accuracy of irreversible hydrocolloid impressions using four different types. To evaluate the dimensional accuracy of irreversible hydrocolloid impression materials with four different impression tray types, and to identify the optimal tray design and material for producing precise dental models. Dentulous maxillary model was taken for the study. The canines and first molars of the model were replaced with metal dies on either side. The molar dies were made with two cusp one buccal and palatal .The trays used in the study were Perforated Rimlock tray, perforated stock metal tray, perforated stock plastic tray, perforated custom tray (self-cure acrylic resin). All the above mentioned trays were modified to get the exact same orientation of the trays every time for making the impressions. Therefore two extra handles are attached laterally on each tray. A hole was made in each handle for the orientation of the tray on tray positioning device. To position the each tray on the model in same orientation was difficult so to overcome this problem a tray positioning device was designed. The antero-posterior distances (A-B and C-D) and cross arch distances (B-C and D-A) in all the groups were compared and found that the dimensional changes in all groups were insignificant except the Perforated stock plastic tray i.e. groups III, which showed highly significant differences The proper impression material and tray combination is crucial and very important to achieve desirable results in terms of dimensional accuracy and the quality of the impressions. Thus the results of the present study should be helpful to the dental practitioners in selection of the impression tray before making impressions with the irreversible hydrocolloid impression material.