Investigation of Conventional vs Nonoriginal CAD/CAM Bars with Production Stage Differences: An In Vitro Precision Study Using a Novel Technique.

Abstract

The aim of this study was to evaluate the precision of fit of bar frameworks fabricated using three different production processes and the effect of changes in the CAD/CAM process steps on the precision of the resulting bar frameworks. Four implants were applied to a mandibular phantom model, and three different production techniques were used to fabricate 30 bar frameworks. In the first group, the bar frameworks were fabricated with the conventional production process (the lost-wax technique; n = 10). In the second group, a CAD/CAM production process was used with digital data collected individually from the master model for the production of each of the final bar specimens (n = 10). In the third group, a CAD/CAM production process was used with the master model being scanned once, and the single resulting data value was used for the production of all final bar specimens (n = 10). The marginal gap between bar frameworks and implants was digitally calculated (ATOS So High-End 3D Digitizer for Small Objects, GOM Inspect). Newman-Keuls multiple comparison tests, a Tukey multiple comparison test, and Pearson correlation tests were applied to the data with a level of significance of P < .05. The mean marginal gap value of group 1 was 95.25 ± 76.15 μm, which was statistically significantly lower than the other groups (P = .0001). For group 2, the mean marginal gap value was 152.00 ± 97.19 μm, whereas for group 3, the mean marginal gap value was 156.7 ± 78.70 μm. Among group 2 and group 3, no statistically significant difference was observed at the mean marginal gap value. The marginal gap values in the CAD/CAM bar framework groups were significantly higher than the conventional bar framework group. Among the CAD/CAM groups, the mean marginal gap values were not statistically significant.