OBJECTIVES:

To compare the influence of different scan patterns, including (i) Occlusal-Lingual Buccal (OLB), (ii) Zigzag (ZZ) and (iii) Dual scan (DUAL) in the accuracy of scans obtained for tapered and square dentate arches.

Material and methods:

Two Maxillary patient models (Square and Tapered) were scanned with the desktop scanner (E4 lab Scanner, 3 Shape®) and used as reference.  In each group, the model was scanned in three different scan patterns: (i) OLB, (ii) ZZ and (iii) DUAL 20 times(n) using EmeraldS Scanner, Planmeca® Scanner. The Scans were exported in STL and superimposed using an inspection software (Geomagic Control X).  Accuracy was evaluated calculating the deviation between tested and reference models using root mean square (RMS) difference. Results were analyzed using Shapiro-Wilk and Two-way ANOVA - Tukey PostHoc Tests.

Results:

The results indicate a statistically significant main effect for arch form (F=9.59/p=0.002), but not for scan pattern (F=0.833/p=0.436) or the interaction between the two (F=0.042/p=0.959). Post hoc analysis reveals that the square arch form is significantly more challenging to scan(p=0.002), compared to the taper arch form.

While the choice of scan pattern did not significantly affect the overall discrepancy, the descriptive data suggests that the OLB pattern resulted in the most discrepancy and the ZZ pattern resulted in the least.

Conclusions:

While square arch form creates more discrepancy tapered arch form, the choice of scan pattern does not appear to have a significant impact on the accuracy of the scan.