无缝冠的制作,均要翻制石膏代型,一般均用橡皮圈翻制三瓣石膏法或调拌石膏放于玻璃板上推平,将代型水平压入石膏中……。橡皮圈市上不好买,“玻璃板法”亦较费时。笔者用废X光胶片剪成长12cm,高5—6cm长方形、一端留有2.5×3.0cm长方形尾部,另一端距边长1.5—2.5cm处用利刀刻下2.6cm两条切口、间距0.5cm(图1)。如此法制作数个,使用时将胶片卷起,将另一端长方形尾部插入另一端切 Seamless crown production, should be cast gypsum generation, usually with a rubber band turned three flap gypsum law or mixing plaster put on the glass to push flat, the generational level into the gypsum ... .... Rubber band is not good on the market to buy, “glass law” is also more time-consuming. I use waste X-ray film to grow 12cm high, 5-6cm high rectangle, leaving 2.5 × 3.0cm rectangular tail at one end, the other end from the edge of 1.5-2.5cm at a knife engraved with 2.6cm two incisions, spacing 0.5cm ( figure 1). This law made a few, when used to roll up the film, the other end of the rectangle into the other end of the tail cut