• The Journal of Korean Academy of Prosthodontics
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• v.46 no.2
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• pp.175-184
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• 2008

Purpose: This study was designed to investigate the fitness of adjustable dental impression trays on the Chinese and the Japanese. Material and methods: Initial design of the adjustable dental trays was developed from the results of the dental arch size of Korean adults. This design was applied to the CAD-CAM process in order to create tray model samples. Simple silicon-base molds were then replicated based on these sample models. Polyurethane injection into the silicon- base molds completed the process of creating a large number of test products. 60 Chinese dental students (male:30, female:30) from the Shanghai Second Medical University and 60 Japanese alumni from the Kumamoto high school (male:30, female:30) were selected for taking irreversible hydrocolloid impression with these trays. The width and length of the impression body were measured on several measuring points by Vernier caliper. The results were analyzed statistically to evaluate the fitness of the trays. Results: 1. Uniform impression material thickness was achieved on the Chinese and Japanese by controlling the width of the tray using stops and beveled guides. The material thickness was generally within the range of 3 mm to 6 mm. 2. In the maxillary tray of the Chinese, average thickness of the impression material of the labial vestibule of the incisal teeth was 6.2 mm, the canine was 5.9 mm and the midpalatal part 10.5 mm and the posterior palatal part 9.7 mm. These were relatively large values. 3. In the mandibular tray of the Chinese, average length of the impression material of the lingual vestibule of first, second premolar contact point was 8.9 mm, the incisal teeth was 7.8 mm and thickness of the labial part of canine was 6.8 mm and premolars 7.0 mm. These were relatively large values. 4. In the maxillary tray of the Japanese, average thickness of the impression material of the labial vestibule of the incisal teeth was 7.4 mm, the canine was 7.7 mm and the midpalatal part 9.1 mm. These were relatively large values. 5. In the mandibular tray of the Japanese, average thickness of the impression material of the labial vestibule of first, second premolar contact point was 8.4 mm, and thickness of the labial part of canine was 7.4 mm. These were relatively large values. Conclusion: This adjustable dental tray shows good accuracy to Korean because it was designed by the analysis of the dental arch size of Korean adult model. With this result, it can be applied to Chinese and Japanese, we can take more easy and accurate dental impressions.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.2
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• pp.185-192
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• 2008

Purpose: This study was designed to investigate the fitness of adjustable dental impression trays on the Caucasian and African American. Material and methods: The size and shape of these trays were designed from the results of the dental arch size of Korean adults. Tray samples were made by CAD-CAM working. Sixty Caucasian (male:30, female:30) and sixty African American (male:30, female:30) were selected for taking irreversible hydrocolloid impression using these trays. The author measured the width and length of impression material on the several measuring points. Results: 1. Uniform impression material width was achieved by controling the width of the tray using stops and beveled guides. 2. In the maxillary tray on the Caucasian, the impression material thickness was measured to be rather great showing thickness of the midpalatal part 13.0 mm. 3. In the maxillary tray on the African American, the impression material thickness was measured to be rather great showing thickness of the midpalatal part 12.0 mm, posterior palatal part 11.0 mm and the labial frenum width was 11.0 mm. 4. In the maxillary tray on the African American, the impression material width of posterior border (0.8 mm) was measured to be small. 5. In the mandibular tray on the Caucasian, the impression material width was measured (2.7-6.7 mm) and posterior border width (2.1 mm) was measured small. The impression material length was measured (2.8-6.7 mm). 6. In the mandibular tray on the African American, the impression material width was measured to be rather great showing width of the labial frenum 9.2 mm and the width of posterior border was measured too small (0.3 mm). Conclusion: This adjustable dental tray shows good accuracy to Korean because it was designed by the analysis of the dental arch size of Korean adult model. With this result, it can be applied to Caucasian and African American, we can take more easy and accurate dental impressions.