Clinical efficacy of polyvinyl siloxane impression materials using the one-step two-viscosity impression technique

Abstract Statement of problem Impression making is a challenging clinical procedure for both patients and dentists. Purpose The purpose of this clinical study was to compare a recently introduced fast-setting polyvinyl siloxane (PVS) impression material with heavy body/light body (HB/LB) combination (Imprint 4; 3M ESPE) (experimental group) with a conventional PVS impression material with HB/LB combination (Imprint 3; 3M ESPE) (control group), using the 1-step 2-viscosity impression technique. Material and methods Two definitive impressions (1 of each material combination) were made of 20 crown preparations from 20 participants. The quality of impressions was rated by 3 evaluators (clinical evaluator, clinical operator, and dental technician) and by the patients for the level of comfort and taste of the impression materials. The order in which the 2 impressions were made with each material combination was randomized for each crown preparation. A paired t test for paired means and McNemar test for paired proportions were used for statistical comparisons (α=.05). Results Participants rated the comfort of the impression making with the experimental group significantly higher than that with the control group ( P =.001). No significant differences were found in participants’ rating for the taste of the impression materials ( P =.46). The viscosity for tray material was rated as significantly better for the control group by the clinical operator ( P =.004). The readability of the impression and visibility around the finish line were rated as significantly better for the experimental group than for the control group ( P