Laboratory accuracy in casting removable partial denture frameworks

An attempt was made to compare the clinical accuracy of two types of cast metals used in the fabrication of removable partial dentures as they were prepared by commercial laboratories. No comparison of the metals could be made, because the discrepancies that were found were too gross and were related to technical error. Suprabulge clasps were placed in less undercut than prescribed. Infrabulge clasps were placed in more undercut than prescribed. The laboratories produced better accuracy when they were informed of the purpose of the cast frameworks than when the frameworks were made without the knowledge that their work would be tested. One laboratory produced better results than the other under similar conditions.