非贵金属烤瓷合金整铸固定桥的适合性研究

Study on Fit of Framework of Nonprecious Metal Alloy for Ceramometal FPD Made of One-Piece Casting

采用 CW—PA(Ni-Cr-Nb)烤瓷合金和 HCAEST(?)磷酸盐结合系包埋料,比较有圈包埋与无圈包埋两种包埋方法和蜡型立即包埋与存放24小时后包埋两种蜡型存放时间,考察三单位金属烤瓷固定桥整铸支架的适合性。结果,在本实验条件下,使用非贵金属烤瓷合金制作的整铸固定桥适合性较差;有圈包埋与无圈包埋之间无统计差异;蜡型不存放与存放24小时之间基本无统计差异;表明铸件的变形是不可避免的,这与固定桥的特殊形状有密切关系。

The purpose of this study is to evaluate the fitness of three-unit FPD framework inone-piece casting made of CW-PA(Ni-Cr-Nb)alloy and invested with HCVEST(?)invest-ment,in comparison of casting ring investing method with ringless method and wax pat-terns invested immediately with those of 24 hours storage time.The specimens were divi-ded into 4 groups.28 castings were made for the experiment.The following conclusions from the results were drawn,No significant difference wasfound in dimensional changes between casts invested with either ring or ringless method.There was a little significant difference in dimensional changes on some sections betweencasts from wax pattern invested immediately and stored for 24 hours.None of casts exhi-bits an ideal fitness and complete seating.Unavoidable distortion of the cast exists.Thediscrepancy greatly attributes to the irregular shape of FPD.