A comparison of two solder registration materials: A three-dimensional analysis

Statement of problem. Use of a segmental indexing/soldering approach for assembly of complete arch implant frameworks has been advocated by some clinicians to achieve a passively fitting framework. To the authors' knowledge, a mathematical assessment using a 3-dimensional (3-D) distortion analysis has not been performed comparing segmental framework assembly to reassembly of 1-piece complete arch frameworks that required sectioning, indexing, and soldering. Purpose. The present study compared the use of 2 indexing materials, autopolymerizing acrylic resin and light-polymerized composite resin, for use ill solder registration of complete-arch implant frameworks using 3 framework/indexing material combinations: gold/light-polymerized composite resin, silver palladium/ autopolymerizing acrylic resin, and silver palladium/light-polymerized composite resin. Material and methods. Five frameworks for cacti alloy/index combination were fabricated, for a total of 15 frameworks. Each framework was fitted to 5 implant abutments. Measurements were made of the initial gold cylinder/abutment Positions for Cacti of the 5 sites for the 15 frameworks. The 3-D spatial orientation of cacti gold cylinder/abutment was calculated prior to the gold cylinders being incorporated into the framework casting and served as the control against which all measurements were compared. After the indexing/soldering procedures, the 3-D spatial orientations of the cylinders were measured, first as 2- and 3-unit solder assembled framework segments and, finally, for complete-arch frameworks. These measurements were recorded in micrometers for linear distortions and degrees for angular distortions using a coordinate measurement machine (CMM). These data were compared and statistically assessed using a 1-way analysis of variance (ANOVA). A Student-Newman-Keuls test was used to determine significance between cylinders within cacti indexing combination. A repeated-measures ANOVA and a Student-Newman-Keuls test were used to determine significance between alloy/index group and cylinders for cacti of the measurement variables with statistical significance at alpha=.05 for all statistical analyses. Results. Mean differences and SDs of total linear change for all groups found dR (total linear change) to be 33.56 +/- 27.70 mu m for gold/light-polymerized composite resin, 34.87 +/- 27.99 mu m for silver palladium/autopolymerizing acrylic resin, and 31.56 +/- 24.37 mu m for silver palladium/light-polymerized composite resin. Total angular change, d theta(R), was calculated to be 0.47 +/- 0.13 degrees for gold/light-polymerized composite resin, 0.46 +/- 0.17 degrees for silver palladium/autopolymerizing acrylic resin, and 0.52 +/- 0.15 degrees for silver palladium/light-polymerizing composite resin. Conclusions. No significant differences were found between alloy/index combinations, except for the measured variable d theta(y) angular change about the Y axis.