Physical properties and additional characteristics of current elastomeric impression materials

Guang Hong, DDS, PhD, Hiroshi Murata, DDS, PhD, Ying-Ai Li, DDS, and Taizo Hamada, DDS, PhD

Department of Prosthetic Dentistry, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan

Purpose: This study evaluated physical properties and additional characteristics of six commercial elastomeric impression materials and effect of a silicone remover on peel bond strengths between impression materials and an acrylic resin tray.
Materials and Methods: Four silicones (Examixfine, Exadenture, Coltex, and President), one polyether (Impregum F) and one polysulfide (Surflex F) were used. One Type 3 (New Plastone) and one Type 4 (New Fujirock) dental stone casts were used. The tests of detail reproduction, compatibility with dental stones, working time and liner dimensional change were tested by means of International Organization for Standardization (ISO) 4823 and Japanese Industrial Standard (JIS) T6513. The surface roughness (Ra) of dental stone casts was measured using a profilometer. The peel bond strengths were measured with mechanical testing device. Statistical analysis was performed using one-way and two-way analysis of variance, Student- Newman-Keuls multiple comparison tests and t-test (α=0.05).
Results: Large differences were not found among the compatibility with dental stone in all type impression materials (p>0.05). The silicone and polyether impression materials indicated the smallest change between 0 day and 1 day of liner dimensional changes than the polysulfide impression material. The Polysulfide impression material exhibited longer working time and setting time, and higher bond strength between acrylic resin trays than the other type of impression materials. When the silicone remover was applied, the values were approximately 0 N/mm.
Conclusion: The physical properties and additional characteristics of current impression materials are different among the material. The silicone remover was useful for removal of polyether and polysulfide impression materials from an acrylic resin tray as well as that of silicone impression materials.(Int Chin J Dent 2005; 5: 80-90.)

Key Words: bond strength, detail reproduction, impression material, physical property, surface roughness.