Accuracy comparison of different intraoral scanners in capturing orthodontic bracket positions: an in vitro evaluation

Abstract

Aim This study aimed to evaluate and compare the accuracy of four intraoral scanners (IOS) in capturing the three-dimensional positions of orthodontic brackets on dental models. Methods Twenty maxillary dental models bonded with MBT stainless steel brackets were scanned using four IOS systems: Primescan, Trios 4, iTero Element 5D, and Medit i700. A high-accuracy laboratory scanner served as the reference standard. Each model was scanned twice with each IOS, yielding 160 datasets. Scans were aligned to the reference using a two-step superimposition protocol, and bracket slot-center deviations were measured in mesiodistal, occlusogingival, buccolingual, and angular dimensions. Trueness, precision, and clinically acceptable deviation rates were analyzed using ANOVA/Kruskal–Wallis tests and intraclass correlation coefficients (ICC). Results Primescan showed the highest trueness, with linear deviations of 0.05–0.07 mm and angular deviations of 0.58–0.62°. Trios 4 demonstrated similar accuracy, remaining within ±0.10mm and ± 1°. iTero Element 5D exhibited greater variation (0.10–0.12mm; 1.12–1.25°), while Medit i700 showed the highest deviations (0.11–0.13mm; 1.29–1.41°). Clinically acceptable deviation rates were 92.5% for Primescan, 88.1% for Trios 4, 76.4% for iTero, and 62.7% for Medit. Precision analysis showed the lowest repeat-scan variability for Primescan (0.03 ± 0.01 mm), whereas Medit displayed the highest variability. ICC values exceeded 0.90 for all scanners. Conclusion Scanner accuracy varied significantly, with Primescan and Trios 4 demonstrating superior trueness and precision. iTero and Medit showed reduced accuracy, particularly in angular measurements. Scanner selection is therefore critical for workflows requiring high-fidelity bracket capture.