Accuracy of different digital scanning techniques and scan bodies for complete-arch implant-supported prostheses

The effect of various scan bodies and scanning techniques on the accuracy and scan time for completely edentulous patients is not well understood. The purpose of this in vitro study was to evaluate the effects of 4 scanning techniques and 5 intraoral scan bodies (ISBs) on the trueness, precision, and scan time in a completely edentulous arch with 4 implants. Five different ISB systems: AF, NT, DE, C3D, and ZI, and 4 different scanning techniques: unmodified master model (NO), glass fiduciary markers placed on the edentulous ridge (GB), pressure-indicating paste brushed over the ridge and palate (PP), and floss tied between the scan bodies (FL), were evaluated. Scan bodies were attached to an edentulous maxillary model with 4 dental implant analogs and scanned by using a structured blue light industrial scanner, and 5 consecutive digital scans of the model were made by using an intraoral scanner and 1 of the 4 techniques (n=5). The scans were superimposed on the master reference model, and the distance deviation and angular deviation of the scan bodies was calculated. The scan time was also recorded. A 2-factor ANOVA was used to examine the effect of scan body and technique on the trueness and scan time, with subsequent Tukey honestly significant difference or Bonferroni-corrected Student t tests. Precision was evaluated by tests for homogeneity of the variances between groups. Reliability for the entire study was evaluated using the intraclass correlation coefficient (α=.05 for all tests). The overall reliability of the study according to intraclass correlations was 0.999. In terms of trueness, no statistically significant interaction was found between the effects of scan body and technique on the distance deviation (P=.246); however, the scan body (P=.031) and technique (P