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Dimensional accuracy of 2 irreversible hydrocolloid alternative impression materials with immediate and delayed
Usama Nassar1, Bayan Hussein, Andrea Oko
1Department of Dentistry, Faculty of Medicine and Dentistry, University of Alberta Edmonton, AB. unassar@ualberta.ca
Objective:
To assess dimensional accuracy and stability of 2 irreversible hydrocolloid alternative impression materials with immediate and delayed pouring.
Methods:
Two alternative impression materials, AlgiNot FS and Position Penta Quick, were compared with a traditional irreversible hydrocolloid, Jeltrate Plus antimicrobial alginate. Impressions were made of a metal model with 4 cylinders of known dimensions, with pouring performed immediately or after 4 hours of storage. A digital micrometer was used to measure cylinder diameter on the model and the poured casts. Dimensional changes were analyzed according to American National Standards Institute/American Dental Association (ANSI/ADA) Specification 19 (2004 version) (α=0.05).
Results:
There were significant differences among the 3 materials, between the 2 pour times and as a function of storage time (multivariate analysis of variance, p<0.001). One-way analysis of variance revealed no significant differences between the 2 alternative impression materials, but changes for these materials differed significantly from those for the traditional impression material for immediate (p<0.05) and 4-hour (p<0.001) pouring. Linear dimensional changes for the 2 substitute materials were within the limits of the ANSI/ADA specification.
Conclusions:
With immediate pouring, both alternative impression materials exhibited minimal dimensional changes, which were maintained or reduced with 4-hour pouring. For both pouring times, these changes were less than 0.5%.
Clinical Significance:
The minimal dimensional changes observed with these irreversible hydrocolloid alternative impression materials after 4 hours of storage may save chairside time and help to produce accurate results for procedures such as partial denture framework, surgical guides, and pediatric and orthodontic devices.
