| 摘要 |
<p>PURPOSE:To reduce time for preheating models, prevent the pars alveolaris mandibulae of a denture base from developing shrink marks, provide good deburring and also good cooling after molding. CONSTITUTION:Models 13, 14 made of gypsum and formed in flasks 11, 12 are previously heated. Nearly the same heating in all is applied to both the models 13, 14 by irradiating far infrared radiation from the upper area at the surfaces of the models 13, 14 in air. In this case, the tooth socket part 13a of the lower model 13 and the tooth part 2 of the upper model 14 are covered with aluminum foil 81, 82. Thus, on the surfaces of the models 13, 14, palate parts 13b, 14b and deburred part 13c, 14c have temp. higher than that of the tooth socket part 13a and the tooth part 2. Thus, only the surface parts of the model 13, 14 dry quickly and increase in temp. Water remains in the models 13, 14 to prevented gypsum from dewatering and contraction.</p> |
