Influence of the color of 3D-printed scan aids on the trueness of complete arch digital scans.

Purpose: To determine the influence of using 3D-printed scan aids in varying colors on the trueness of digital scans.

Materials and methods: A master cast with five multi-unit analogues was scanned. The acquired dataset was exported to standard tessellation language (STL) file format to serve as the reference STL. 3D printing of the prototype in five distinct colors (beige [SA^BEIGE], grey [SA^GREY], white [SA^WHITE], red [SA^RED], and blue [SA^BLUE]) of polylactic acid filament was executed. The experimental STLs of each color group were aligned to the reference STL. RMS values were solely computed for the scan bodies. Based on the centers of the created best-fit and offset planes, scan bodies were converted into virtual cylinders. Cartesian coordinates of each cylinder were acquired. Subsequently, angular (AD) and linear deviation (LD) values were calculated. LD was further examined separately along the x, y, and z axes. Data were statistically analyzed.

Results: According to the results of one-way ANOVAs, significant differences were detected among color groups on AD, LD, RMS estimate error, ∆x, ∆y, and ∆z data. The lowest AD and LD values were exhibited by the SA^GREY group in all implant sites. The SA^GREY group was followed by the SA^BEIGE, SA^WHITE, SA^RED, and SA^BLUE groups.

Conclusions: The SA^GREY outperformed the other groups in terms of trueness. Although the LD values of all color groups were below the threshold value (<100 µm), only the AD values of the SA^GREY, SA^BEIGE, and SA^WHITE groups were clinically acceptable (<0.5°).