PubMed · 4870901
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Y Murata. 1967. [Individual impression tray].. https://pubmed.ncbi.nlm.nih.gov/4870901/
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The purpose of this study was to inspect visually, the dynamics of the impression flow at seating of the impression tray. The effects of the relief and the escape hole of the impression tray on the impression flow were also examined. Three types of the transparent impression tray (flat tray, relief tray and escape hole tray) were prepared. Transparent silicone polymer was put on the impression tray surface. Four drops of the dark blue silicone impression material was injected into the transparent silicone polymer on the impression tray. The impression tray was seated on the model of the denture-supporting mucosa. The movement of the four drops caused by the impression flow was visually recorded with the video camera and examined. The result for the flat tray showed that the impression material moved from inside to the outside. It was also shown that the speed of the moved impression material increased as the seating of the impression tray advanced. The results for the relief tray and the escape hole tray showed the effect of the relief and the escape hole prepared to the impression tray on the speed and the direction of the flow of the impression material.
A protocol for standardizing the production of an artificial test food was established and its reliability was determined. An artificial test food was selected based on its superior properties compared with natural foods. The primary emphasis during production was the incorporation of all 3 cm of paste-hardener and thoroughly kneading the material for 30 s. The curing process was studied to determine overall setting time. After at least 30 min, the physical properties of the test food were ready to be measured. The overall mean hardness of the test food was 489 +/- 60 load grams. Random error between operators was +/-16 load grams while batches differed by +/-13 load grams and individual tablets differed by +/-15 load grams. This protocol provides a reliable standardized method for future masticatory performance studies.
Excellent fixed-prosthodontic impressions are ensured with the presence of healthy soft tissue, atraumatic tooth and soft-tissue preparation, use of packing cords when indicated, routine use of astringents and taking enough time to accomplish the preimpression procedures thoroughly. Currently advertised products that supposedly eliminate the difficulty of fixed-prosthodontic impressions and the need for cords have decreased some of the frustrations of impression making, but the challenge remains. Excellent impressions require accurate and stable impression materials, time, conscientious and thorough techniques, attention to every detail, good support staff and a working knowledge of all aspects of the concepts involved.