5 In England in 1857, Charles Stent combined gutta percha with an animal fat (stearine) and talc to develop a modeling compound. 4 It was commonly used up to the 1900s, and was often fractured in order to remove it from undercuts, then reassembled outside the mouth. The name, plaster of Paris, was coined from a large gypsum deposit found at Montmartre in Paris, France. 3 Other materials were introduced in the 1800s, including gutta percha and plaster of Paris. Although a poor impression material by today’s standards, it was capable of being removed from undercut areas in the mouth. History of the Dental Impressionīeeswax, used by a German surgeon, 2 is the first referenced material used to make dental impressions. Otherwise, we can wander through our entire dental career trying every technique and never achieving sufficient confidence in any one particular one. Taking an impression is a craft and, as with any other skill, proficiency comes from practice but first, the technique to practice must be decided upon. Comments from practicing dentists to laboratory technicians as to how to handle voids in impressions have been remarkable and range from, “I pay you the big bucks to find the margins,” to, “Just connect the dots.” Therefore, there are 36,000,000 crowns that do not have all margins taken each year.” As a dentist/laboratory technician, I can concur with that statement, although I did not realize the number was that high. On his instructional videotape “The Perfect Impression,” Gordon Christensen, DDS, MSD, PhD, made the statement, “40,000,000 impressions are taken each year 90% do not have all margins taken. Clinicians spend much of their time trying different materials and methods searching for the right technique. Among the over 600 hundred brands of impression material, 1 produced by over 30 manufacturers, one might think that there would be at least one ideal product, which would produce the perfect impression every time. Only in dentistry does one get a second chance to make a good first impression.

Double impression dental