Comparison of different artificial landmarks and scanning patterns on the complete-arch implant intraoral digital scans

Abstract

ObjectivesThe purpose of this study was to compare the effects of four types of artificial landmarks and three different scanning patterns on the accuracy of complete-arch implant intraoral digital scans. MethodsAn edentulous mandibular model with 4 dental implants (Osstem) was prepared as the master reference model (MRM) and scanned with laboratory scanner (E4 Lab Scanner®). Then, the model was modified with four artificial landmarks: (i) CON- unmodified MRM, (ii) PIP- pressure-indicating paste brushed over the edentulous ridge, (iii) LD- liquid dam markers placed on the edentulous ridge, and (iv) FL- floss tied with pattern resin between the scan bodies. In each group, the modified model was scanned with three different scanning patterns: (i) LB- linguo-buccal pattern, (ii) SS- s-shaped pattern, and (iii) QU- quadrant pattern (n = 10/subgroup) using an intraoral scanner (Trios®4). Scans in STL format were exported and superimposed with MRM file using an inspection software (Geomagic Control X). Accuracy (trueness and precision) was evaluated by calculating the deviation, root mean square (RMS). Results were analyzed using two-way ANOVA, one-way ANOVA and Games-Howell (α = 0.05). ResultsSignificant differences in accuracy values were found across different artificial landmarks and scanning patterns as the LD artificial landmark with QU pattern showed the highest accuracy. The lowest accuracy was recorded in CON with LB pattern, PIP artificial landmark with LB pattern, and FL artificial landmark with SS pattern. ConclusionsThe artificial landmarks and scanning patterns had a significant effect on the accuracy of the complete-arch implant intraoral digital scans. Clinical SignificanceWhen performing complete-arch digital scans with four dental implants, clinicians should select proper artificial landmark and scanning pattern, as the artificial landmark and scanning pattern significantly affect the accuracy of the scan when using an intraoral scanner. ®