Determination of the accuracy of wax interocclusal registrations

This study established a method whereby various materials used to register interocclusal recordings may be tested, measured, and compared. Two brands of wax were tested in storage environments of air, tap water, and cold water at four storage time intervals of 2, 6, 24, and 48 hours under seating pressures ranging from no pressure to heavy pressure. Using a factorial experimental design for the investigation of the main and interactive effects of these variables, the following were observed: 1. Complete closure under a pressure comparable to those of a clinical setting (ixe. = 172 p.s.i.) was not achieved when wax was present. 2. Storage of the wax registration in cold water showed the greatest change, while air cooling showed the least change. 3. There was a considerable vertical and slight horizontal change when the model was gently placed into a previously formed wax registration. Upon application of pressure, there was a reduction of vertical change followed by a proportional increase in horizontal displacement. 4. The accuracy of an interocclusal recording wax must be considered in terms of the many variables responsible for dimensional change. 5. Even under the highly controlled conditions of this study, exact reproduction of the original wax recordings was never achieved.