In vitro scanning accuracy using different aids for multiple implants in the edentulous arch

Optical impressions of implants in the edentulous arch are challenged by the absence of distinct surface morphology between multiple implant scan bodies. The purpose of this in vitro study was to evaluate a newly developed scan aid in various designs and colors to improve the accuracy of multi-implant scans.

A universal scan aid in three different designs (circular, square, irregular) and three different materials (colors: beige, gray, white) was applied to the implant scan bodies of a master model of six implants in an edentulous maxilla. Ten scans using an intra-oral scanner of each scan aid were acquired. Reference scanning was performed using a desktop optical scanner. Alignment of scans was performed at the first scan body in a three-dimensional modeling and inspection software and deviations for trueness and precision were calculated using the signed nearest-neighbor method and then statistically analyzed (α = .05).

Overall, the beige irregular scan aid had the highest trueness and showed significant differences compared to unsplinted scans. The precision showed more heterogenous results and decreased when using the scan aid. Ease of use was observed with the irregular gray scan aid due to its increased elongation at break.

The evaluated scan aid led to improved trueness when compared to unsplinted scans. Even though the irregular design in beige color showed highest trueness, the poor fracture strength of the tested material requires further improvement.