Randomized Prospective Clinical Trial using a New Automixed Putty VPS-Material

Objectives: A standardized mixing process of impression materials is supposed to have an impact with regard to the accuracy of an impression and may therefore influence the fit of the final restoration. Recently, a new auto-mixed putty vps-impression material was introduced to the market. Hence the aim of this study was to test the accuracy of this newly introduced impression material (Express Penta Putty = EPP, 3M ESPE) and compare it to a commercially available hand-mixed material (Panasil Putty fast set = PPFS, Kettenbach) using a randomized, prospective clinical study design. Methods: 38 impressions were taken from 70 prepared abutment teeth using a two-step putty-wash technique. The according impression material was randomly assigned. Impressions and dye models were assessed using a standardized case record form with defined criteria for the quality of the impression (Alpha, Bravo, Charlie, Delta). Number of retries were documented. Finally, accuracy was determined measuring the max. marginal discrepancies of the final castings in the patients mouth using five measuring explorers with standardized tip diameters of 100µm, 200µm, 300µm, 400µm and 500µm at 6 predefined measuring sites per tooth. Data were subjected to parametric statistics (Fishers exact test; p=0.05). Results: The assessment of the quality of the impressions revealed no significant differences between the two materials tested (p>0.05). EPP showed a significantly higher number of Alpha ratings for the dye models assessed (p<0.05). EPP showed a higher amount of castings with max. marginal discrepancy of less than 200 µm. For both materials, the number of retries were not significantly different (p>0.05). Conclusions: Under the limits of the study it can be concluded, that the newly introduced vps-material - mixed in an auto-mixing device - shows clinical results, which are comparable or better in performance than the conventional hand-mixed material tested.