Impact of dentition alignment, scanning strategy and operator experience on the accuracy and time of intraoral scanning: an in vitro study

BACKGROUND: The accuracy of intraoral scanning can vary across clinical scenarios. The aim of this study was to evaluate the effects of dentition alignment, scanning strategy, and operator experience on the trueness, precision, and efficiency of intraoral scanning. METHODS: Three maxillary models representing aligned, crowded, and spaced dentition were scanned using an intraoral scanner (Alliedstar AS100). Three experienced operators and three inexperienced dental students performed intraoral scanning using three scanning strategies, each repeated ten times. Trueness and precision were quantified using root mean square (RMS) deviations following best-fit alignment in Geomagic Control X software, and scanning time was recorded. Data were analyzed using generalized linear mixed models. RESULTS: Scanning strategy and dentition alignment significantly affected trueness and precision (P < 0.05), whereas operator experience showed no significant main effect. Non-linear strategies produced lower RMS deviations than the linear strategy (P < 0.001). Spaced dentition showed the highest deviations (0.16 ± 0.12 mm), while crowded dentition exhibited the lowest (0.13 ± 0.10 mm). Scanning time was significantly influenced by scanning strategy and dentition alignment, with the sweeping non-linear strategy showing the shortest acquisition time (P < 0.05). Tooth-level analysis revealed site-specific differences in scanning accuracy. CONCLUSIONS: Dentition alignment and scanning strategy are primary determinants of intraoral scanning performance, whereas operator experience has a limited influence on full-arch accuracy.