Trueness and precision of mandibular complete-arch implant scans when different data acquisition methods are used.

Abstract

OBJECTIVES

To evaluate the effect of different data acquisition methods on the trueness and precision of mandibular complete-arch implant scans.

METHODS

An edentulous polyurethane master mandibular model with 6 implants was digitized by using an industrial-grade blue light scanner (ATOS Core 80 5MP) to obtain a master standard tessellation language (MSTL) file. The master model was also digitized by using either direct digital workflow with a stereoscopic camera (iCam 4D (IM)) or intraoral scanners (CEREC Primescan (PS) and Trios 4 (T4)) or indirect digital workflow with laboratory scanners (inEos X5 (X5) and CARES 7 (S7)) to obtain test-scan STLs (n=10). All STL files were imported into a metrology-grade analysis software (Geomagic Control X 2020.1) and test-scan STLs were superimposed over MSTL. The root mean square method was used to calculate surface deviations, while angular deviations were also calculated. Kruskal-Wallis and Dunn's tests were used to evaluate measured deviations (surface and angular) for trueness and precision (α= .05).

RESULTS

X5 and S7 had the lowest, and IM had the highest surface deviations (P≤.036). The angular deviations of PS were lower than those of X5, S7, and IM (P≤.008). When surface deviations were considered, T4 had the lowest precision among tested scanners (P≤.002), and the scans of IM had higher precision than those of PS (P=.003). Scanner type did not affect the precision of the scans when angular deviations were considered (P=.084).

CONCLUSIONS

The data acquisition method affected the trueness (surface and angular deviations) and precision (surface deviations) of mandibular complete-arch implant scans.

CLINICAL SIGNIFICANCE

Tested data acquisition methods may be feasible to digitize mandibular complete-arch implants considering the deviations of the scans, which were in the range of previously reported thresholds, and the high precision of scans. However, the frameworks fabricated with the direct digital workflow that involves the scans of the stereoscopic camera might require more adjustments than those fabricated by using the scans of other tested scanners.