Influence of ambient light conditions on the accuracy and scanning time of seven intraoral scanners in complete-arch implant scans

Purpose: The purpose of this in vitro study was to evaluate the effect of ambient light illuminance on the accuracy and scanning time of different intraoral scanners (IOSs) in complete-arch implant scans. Material and methods: Seven IOSs (TRIOS 3, Primescan, Element 5D, i700, i500, CS3700, and CS3600) at 5 ambient lighting illuminances (100, 500, 1000, 5000, and 10 000 lux) were evaluated. An edentulous cast with 4 implants was selected as the master model. An implant scan body was tightened on each implant. The cast was digitized by using a laboratory scanner to obtain a reference standard tessellation language (STL) file, and 50 scans (10 per ambient light condition) were recorded with each IOS. Scanning time was recorded by using a digital chronograph. Intraoral scan deviations were calculated by using a 3D metrology software program (Geomagic Control X). Kruskal-Wallis and pairwise comparison tests were used to analyze the data (a=0.05). Results: The trueness and precision values obtained for each IOS tested were significantly different under the varying lighting conditions assessed. TRIOS 3 (34.0 +/- 3.3 pm trueness; 24.5 +/- 14.9 pm precision), Element 5D (34.5 +/- 7.1 pm trueness; 25.9 +/- 7.6 pm precision), and CS3700 (34.9. +/- 13.0 pm trueness; 34.6 +/- 19.2 pm precision) performed better under 100 lux illumination, CS3600 (69.5 +/- 24.0 pm trueness; 36.6 +/- 20.1 pm precision) at 500 lux; i500 (36.2 +/- 5.1 pm trueness; 21.4 +/- 6.8 pm precision) at 1000 lux; i700 (34.8 +/- 2.2 pm trueness; 15.4 +/- 5.0 pm precision) at 5000 lux, and Primescan (37.4 +/- 37.3 pm trueness; 26.2 +/- 26.2 pm precision) at 10,000 lux. Additionally, the scanning time was different under different illuminance for each IOS. The fastest IOS in all light conditions was Primescan, with significant differences with all the groups (P<.01), followed by TRIOS 3 in all groups except under 100 lux illumination, where i700 was the second fastest. Conclusions: Ambient light influenced the accuracy and scanning time of IOSs assessed; however, the effect was not the same for all devices. It is necessary to optimize ambient light illuminance for each IOS to maximize scanning accuracy.