Technology is shaping the future of healthcare provision, not least in Orthodontics.To overcome difficulties associated with conventional techniques, impressions with IOS (Intraoral Scanner) and CAD/CAM (Computer Aided Design and Manufacturing) technologies were developed for dental practice. The last decade has seen an increasing number of optical IOS devices, and these are based on different technologies, the choice of which may impact on clinical use. An understanding of the IOS technology is necessary for any practitioner to have a successful clinical strategy during the scanning of the prepared teeth.