Gary Frey1, Huan Lu, John Powers. 1. University of Texas Dental Branch at Houston, Department of Restorative Denistry and Biomaterials, Texas 77030, USA. Gar.N.Frey@uth.tmc.edu
Abstract
BACKGROUND: A commercial mechanical mixer is available to make the mixing of alginate more convenient and more consistent for the practitioner; however, there is very little information on the mechanical properties of alginate mixed with this device as compared with hand mixing. PURPOSE: To compare the mechanical properties of alginate impression materials mixed with a mechanical mixer (Alginator II, Cadco) and hand mixing. MATERIAL AND METHODS: Three alginate impression materials (Identic, Jeltrate, and Kromopan) were tested. Strain in compression, elastic recovery, and compressive strength were measured according to ANSI/ADA specification no. 18-1992; tear energy was measured using a pants tear test. Five specimens were prepared for each group with 12 groups for the mechanical mixer and 12 groups for hand mixing, for a total of 120 specimens. A two-way analysis of variance and Fisher's PLSD test at the 0.05 level of significance were used to analyze the data. RESULTS: There were statistically significant differences in properties among the materials, but mixing technique had no statistically significant effect on strain in compression and tear energy. CONCLUSION: The mechanical mixer improved elastic recovery and compressive strength of the alginate impression materials tested and had no effect on strain in compression and tear energy. A mechanical mixer facilitates the mixing of alginate impression materials and improves some mechanical properties.
BACKGROUND: A commercial mechanical mixer is available to make the mixing of alginate more convenient and more consistent for the practitioner; however, there is very little information on the mechanical properties of alginate mixed with this device as compared with hand mixing. PURPOSE: To compare the mechanical properties of alginate impression materials mixed with a mechanical mixer (Alginator II, Cadco) and hand mixing. MATERIAL AND METHODS: Three alginate impression materials (Identic, Jeltrate, and Kromopan) were tested. Strain in compression, elastic recovery, and compressive strength were measured according to ANSI/ADA specification no. 18-1992; tear energy was measured using a pants tear test. Five specimens were prepared for each group with 12 groups for the mechanical mixer and 12 groups for hand mixing, for a total of 120 specimens. A two-way analysis of variance and Fisher's PLSD test at the 0.05 level of significance were used to analyze the data. RESULTS: There were statistically significant differences in properties among the materials, but mixing technique had no statistically significant effect on strain in compression and tear energy. CONCLUSION: The mechanical mixer improved elastic recovery and compressive strength of the alginate impression materials tested and had no effect on strain in compression and tear energy. A mechanical mixer facilitates the mixing of alginate impression materials and improves some mechanical properties.