Azizogli M A, Catania E M, Weiner S
University of Medicine and Dentistry of New Jersey, New Jersey Dental School, Newark, NJ 07103, USA.
J Prosthet Dent. 1999 Apr;81(4):392-8. doi: 10.1016/s0022-3913(99)80004-3.
A working cast with dies that accurately record the prepared abutments, surrounding soft tissues, and adjacent and opposing teeth is necessary.
This study compared the accuracy of the direct and transfer coping methods in recording the vertical and horizontal dimensional relationship of a pair of removable dies in a working cast before and after separation from the stone base. Among the procedures used for making impressions of abutments for fixed partial dentures, the transfer coping procedure has specific advantages. In particular, where there are multiple abutments, this procedure, in which individual impressions are made of the abutments, transfer copings are made, and a transfer impression of the copings is used for seating the dies and fabrication of a dental stone base, is useful.
Two groups of working casts were fabricated from a stone master cast containing 2 ivorine teeth to simulate abutments. The first group of working casts was fabricated directly from the elastomeric impression of the abutments using a 2-pour procedure. The second group of working casts was made using the transfer coping procedure.
When the interdie dimensions in each group were compared with that of the master cast, after separation and replacement of the dies in the stone base, the differences were less than 100 microm and similar for both the direct and transfer coping techniques.
These findings show that either procedure is equally effective in positioning the dies in the working casts.
需要一个带有铸模的工作模型，该铸模能准确记录预备好的基牙、周围软组织以及相邻和对颌牙齿的情况。
本研究比较了直接法和转移法在记录工作模型中一对可摘铸模在与石膏底座分离前后的垂直和水平尺寸关系方面的准确性。在用于制作固定局部义齿基牙印模的方法中，转移法有其特定优势。特别是在有多个基牙的情况下，该方法很有用，即分别对基牙制作印模、制作转移帽，然后使用转移帽的转移印模来放置铸模并制作石膏底座。
从一个包含两颗象牙质牙齿以模拟基牙的石膏母模制作两组工作模型。第一组工作模型直接通过对基牙的弹性印模采用二次灌注法制作。第二组工作模型采用转移法制作。
当将每组中铸模间尺寸与母模的尺寸进行比较时，在铸模从石膏底座分离并重新放置后，差异小于100微米，直接法和转移法的差异相似。
这些结果表明，在将铸模放置于工作模型中时，这两种方法同样有效。
