Comparison of intraoral and extraoral scanners on the accuracy of digital model articulation.

Digital dental technology is increasingly becoming an integral part of the modern orthodontic practice. The accuracy of digitally articulated models is critical when developing orthodontic treatment plans.

OBJECTIVE: to determine the accuracy of model articulation generated by extraoral and intraoral scanners.

DESIGN: One extraoral scanner with a wax (EOW ) or vinyl polysiloxane bite registration (EOVPS ), and three intraoral digital scanners utilizing confocal static (IOCS ), confocal continuous (IOC C ), and blue LED light technologies (IOLED ) were used.

METHODS: On each scanned image (n = 25 per group), measurements between the maxillary and mandibular molars and canines were performed and then compared to the gold standard values. A deviation of ± 0.5 mm from the gold standard value was considered acceptable. The significance level was kept at 0.05.

RESULTS: IOCS and IOCC were accurate for all six interarch measurements. IOLED and EOVPS groups produced the next most accurate articulation of the digital models. EOW group resulted in the least accurate articulation. Also, of the software platforms used, the OrthoCAD™ was found to be the most accurate system for making measurements on digital casts.

CONCLUSIONS: Only the scanners with the confocal imaging technology produced accurately articulated models. Differences between the scanners may be related to measurement errors inherent to the technologies employed and the software systems used to process the images.