Effect of a modified scanning technique on the accuracy of complete-arch implant scanning: An in vitro study

Background: This in vitro study aimed to investigate the accuracy of a modified scanning technique that incorporated a simple scan aid (SSA) and a novel scanning pattern (segmented scanning pattern, SSP) for complete-arch implant scanning. Methods: An edentulous maxillary stone cast with 4 parallel analogs was used as the master model. 10 scans were performed with an intraoral scanner (Trios3) using different scanning methods: a conventional scanning pattern (CSP) without SSA (Group I), CSP with SSA (Group II), SSP with SSA (Group III) and conventional splinted open-tray impression (Group IV). The reference scan was obtained by digitizing the master model using a dental laboratory scanner. The related files were imported into inspection software for trueness and precision assessment. One-way ANOVA, Kruskal-Wallis, SNK- q and Bonferroni test were used to evaluate the values. The level of significance was set at α=0.05. Results: For the global accuracy assessment (trueness and precision), group I exhibited the largest linear and angular deviation ( P <0.001) followed by group II ( P <0.001). For local accuracy assessment, all intraoral scan bodies (ISB A, B, C, and D) exhibited smaller linear and angular deviations in group III ( P <0.05) and group IV ( P <0.05) than that in group I. No differences were found between group III and IV ( P >0.05), either in the overall or local accuracy assessment. Conclusions: SSA combined with SSP could significantly improve the accuracy of complete-arch digital implant impressions.