There are a great amount of materials and techniques to use during dental prosthesis production that may confuse the dentist at the time of choice. Material's choice should be done considering ideal chemicophysical and biological properties and high detail reproduction.

The present study aimed to test the influence of differents impression materials and storage times on the dimensional accuracy of casting models.

Four elastomeric materials– polysulfide, polyether, condensation silicone and addition silicone–were used to reproduce a master model of human teeth which were prepared for metaloceramic fixed prosthodontics. Six reference points were established on each tooth in order to determine four intervals: MD–mesial-distal, BL–buccal-lingual and CO–cervical-occlusal distance from premolar, and INT– interpillar distance–from the distal surface of the premolar to the mesial surface of the molar. The impressions were stored for half, 2 and 12 hours and pondered with a type IV gypsum.

Cast measurements data were subjected to ANOVA (4 × 3), Tukey's – α = 0.05, Kruskal-Wallis and Dunn's tests – α = 0.05. The interaction between materials and storage time presented statistically significant for VP and CO intervals. For each storage time, materials presented dimensional alteration statistically significant.

Impression materials accuracy was affected by the storage time. All materials presented different dimensional accuracy when evaluated in a same period of time. Polysulfide was the only material that presented stable behavior over the time.

Gonçalves FS, de Freitas Oliveira W, Soares LA, Carlo HL, da Mota AS, Popoff DAV, Soares CJ. Impression Materials and Storage Time Influence on Cast Models Accuracy. Int J Experiment Dent Sci 2013;2(1):18-23.