Objectives: To develop a novel auxiliary device for improving the accuracy of intraoral implant scanning in the complete-edentulous arch.
Materials and methods: A standard model of edentulous maxilla with six dummy implants was prepared. Scan bodies were attached to the model, which was scanned by a laboratory scanner. A simulated mucosa (Group 0), a resin base (Group 1), a resin base with a cuboidal reference block and 4 fiduciary spheres (Group 2) or artificial teeth (Group 3) in between the implants were mounted on the model, respectively. Each group were consecutively scanned using an intraoral scanner (n = 10). The scans were analysed for trueness and precision in inter-implant distances and angles by inspection software. Effects of the auxiliary device and different quadrants on the accuracy of complete-arch intraoral scanning were analysed by two-way ANOVA.
Results: Significant effects of the auxiliary device and quadrant were found on both linear and angular accuracies. The lowest linear accuracy was found in group 0. Group 1 and group 3 showed the best linear accuracy in quadrant 1 and quadrant 2, respectively. Group 2 showed the least angular precision among the three groups.
Conclusions: The three designs of auxiliary devices significantly improved the accuracy of complete-arch intraoral implant scanning. The base-only design showed good scanning accuracy in a single quadrant, while the base with tooth-shaped landmarks design showed better accuracy in cross-arch. The fiduciary spheres might compromise the precision of scanning.
Keywords: dental implants; dimensional measurement accuracy; edentulous; imaging; jaw; quality improvement; three-dimensional.
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