Three-dimensional evaluation of the repeatability of scanned conventional impressions of prepared teeth generated with white- and blue-light scanners

Statement of problem. Digital scanning is increasingly used in prosthodontics. Three-dimensional (3D) evaluations that compare the repeatability of the blue-light scanner with that of the white-light scanner are required. Purpose. The purpose of this in vitro study was to evaluate the repeatability of conventional impressions of abutment teeth digitized with white- and blue-light scanners and compare the findings for different types of abutment teeth. Material and methods. Impressions of the canine, premolar, and molar abutment teeth were made and repeatedly scanned with each scanner type to obtain 5 sets of 3D data for each tooth. Point clouds were compared, and error sizes per tooth and scanner type were measured (n=10). One-way ANOVA with Tukey honest significant differences multiple comparison and independent t tests were performed to evaluate repeatability (alpha=.05). Results. Repeatability (mean +/- SD) of the white- and blue-light scanners for canine, premolar, and molar teeth was statistically significant (means: P=.001, P<.001, P<.001; SD: P<.001, P<.001, P=.003). Means of discrepancies with the white-light scanner (P<.001) were 5.8 mu m for the canine, 5.9 mu m for the premolar, and 8.6 mu m for the molar teeth and 4.4 mu m, 2.9 mu m, and 3.2 mu m, respectively, with the blue-light scanner (P<.001). Corresponding SDs of discrepancies with the white-light scanner (P<.001) were 15.9 mu m for the canine, 23.2 mu m for the premolar, and 14.6 mu m for the molar teeth and 9.8 mu m, 10.6 mu m, and 11.2 mu m, respectively, with the blue-light scanner (P=.73). Conclusions. On evaluation of the digitized abutment tooth impressions, the blue-light scanner exhibited greater repeatability than the white-light scanner.