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, square root deltaX2 + deltaY2 + deltaZ2, 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.