title: Distortion of impression materials used in the double-mix technique.
abstract: According to the so-called double-mix technique for impression taking, a material of high and one of low viscosity set against each other. We found that a distortion of the joined materials occurred which may compromise the precision of the impression. The distortion of such combinations of materials of high and low viscosity was measured on beam-like specimens. Significant differences between materials were observed. The phenomenon may be explained by a swelling of the material of low viscosity. The swelling may be associated with a diffusion of unreacted compounds from the material of high viscosity into the material of low viscosity. Measurements of the swelling of specimens immersed in the catalyst component of unset material showed an increase in length of 2-5%.
authors.affiliation: Institute of Dental Materials and Technology, Royal Dental College, Copenhagen, Denmark.
authors.forename: G F
authors.initials: GF
authors.lastname: Petersen
authors.forename: E
authors.initials: E
authors.lastname: Asmussen
mesh_terms: D003760:Dental Impression Materials / Q000737:chemistry*; D003761:Dental Impression Technique; D004058:Diffusion; D007101:Immersion; D011145:Polyvinyls / Q000737:chemistry; D012833:Siloxanes / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors; D014783:Viscosity
chemical_list: D003760:Dental Impression Materials; D011145:Polyvinyls; D012833:Siloxanes