Impact of orthodontic brackets on intraoral and extraoral scans

The purpose of this study was to evaluate whether the presence of orthodontic brackets influences the accuracy of digital models generated by intraoral and extraoral scanning from the same patients.

Eighteen orthodontic patients in permanent dentition underwent full-arch intraoral scanning with a CEREC Omnicam scanner (Dentsply Sirona, York, Pa). Alginate impressions from each patient's arch were taken, and plaster models were made and scanned. Intermolar, intercanine, and mesiodistal width of the incisors were measured on 2 digital and 1 plaster models. Analysis of variance or Friedman's test was used, with differences between pairs verified by the Bonferroni test or Wilcoxon test, respectively. Both digital models were superimposed using surface-based registration.

Lin's lowest coefficient of agreement was 0.960 (95% confidence interval, 0.900-0.984), which was clinically adequate. No statistically significant differences between the 3 types of model measurements were observed, except for the mandibular left lateral incisor in which scanned intraoral digital models presented Δmedium of 0.05 mm, which was higher than the plaster model. The superimposition of the extraoral and intraoral digital models revealed a minimum difference between models with a mean of means of 0.12 ± 0.03 mm.

Brackets bonded to teeth affected intraoral scanning; however, the intraoral digital models are clinically comparable and present fewer distortions than plaster models. Moreover, measurements on intraoral and extraoral digital models are excellent in terms of trueness and precision and can be used clinically and in plaster models.