DISTORTIONS IN INDEXING METHODS AND INVESTING MEDIA FOR SOLDERING AND REMOUNT PROCEDURES

A three-dimensional distortion analysis was made of seven indexing-investment systems and six indexing-remount systems. Measurements were made to within ±0.005 mm with a Nikon Profile Projector and a linear variable differential transformer (LVDT); distortions (linear and rotational) were calculated by means of a PDP 11/40 computer system. Mean vector displacements, sqrt(Δ X2 + Δ Y2 + Δ Z2), were calculated, and a statistical evaluation of the data was completed. The results of the study indicate:1.The zinc oxide-eugenol (ZOE) indexing-investment system produced a narrower range and a significantly smaller mean distortion than the other six indexing-investment systems.2.The ZOE-stone remount technique showed significantly less distortion than the ZOE-low-fusing metal or the ZOE-acrylic resin techniques.3.The polyether-stone remount technique demonstrated significantly less distortion than either the polyether-low-fusing metal or the polyether-acrylic resin system.4.The polyether-stone remount system was not significantly different from the ZOE-low-fusing metal system.5.The ZOE-stone remount technique demonstrated a smaller range of distortions, but those distortions were not significantly different from those of the polyether-stone remount technique. © 1979 The C. V. Mosby Company.