2023 Volume 57 Issue 1 Pages 197-202
The digital images of abutment teeth obtained by optical scanners tend to have rounded sharp edges. This rounding can result in an ill-fitting fixed prosthesis. Ridgeline reconstruction restores the rounded edges of the digital abutment tooth image back to sharp edges, improving the margin accuracy of the CAD/CAM crown. However, the reproducibility of ridgeline reconstruction, including the associated manual operations, has not been clarified. In this study, we investigated this reproducibility. Prepared artificial teeth were scanned with a laboratory scanner, and standard tessellation language (STL) data were obtained. The region of the scan data corresponding to the finish line of the abutment tooth was manually isolated, and ridgeline reconstruction was performed with polygon editing software. We then measured the area above the finish line of the digital abutment tooth, the increased volume, and the length of the finish line. Systematic error for these three measured items were examined with repeated measures ANOVA and the magnitude of random error was examined with intraclass correlation coefficients. The reproducibility of ridgeline reconstruction indicated no systematic errors and relatively good reproducibility. (J Osaka Dent Univ 2023; 57: 197-202)
