A comparative study assessing the precision and trueness of digital and printed casts produced from several intraoral and extraoral scanners in full arch and short span (3-unit FPD) scanning: An in vitro study.

PURPOSE

To compare precision and trueness of digital and printed casts produced from several intraoral and extraoral scanners in full arch and short span scanning.

MATERIALS AND METHODS

A fully dentate maxillary phantom cast was used to represent full arch scanning, and a mandibular phantom cast, including posterior 3-unit fixed partial denture preparations to represent short span scanning. Reference casts (RCs) were fabricated and scanned 10 times by a reference extraoral scanner (Medit T510, Seoul, Korea) to provide reference digital casts. RC was then scanned 10 times by 5 scanners: 2 intraoral scanners (Trios 3shape [Trios 3] and Dental Wings [DW]), and 3 extraoral scanners (3shape E3 [E3], S600 ARTI [S600], and Ceramill Map 600 [M600]). Digital standard tessellation language (STL) files obtained from the 5 scanners were sent to a stereolithography 3D printer to fabricate printed casts. Trueness was obtained by comparing STL files of each digital/printed cast to the RC, while precision was obtained by comparing the digital/printed STL file of each scanner to the other files of same digital/printed group. The lower the precision and trueness values, the higher the accuracy of casts. Multivariate analysis of variance was performed to assess the association of precision and trueness with the type of scanner, type of cast, and scanning span.

RESULTS

There was a significant difference in precision and trueness of casts produced from different scanners (p <0.001). The lowest precision and trueness were demonstrated by casts produced from DW. Digital casts showed significantly higher precision and trueness compared to 3D printed casts (p <0.001). Regarding the scanning span, full arch scanning showed significantly lower precision and trueness than short span scanning (p <0.001).

CONCLUSIONS

Extraoral scanners exhibited higher trueness and precision than intraoral scanners. Trios 3 showed comparable accuracy to that of the studied extraoral scanners in the case of short span scanning. DW was the least accurate scanner in all studied groups, while E3 showed the highest accuracy level among the mentioned scanners. Digital casts showed higher trueness and precision compared to 3D printed casts.