Assessing accuracy in measurements of orthodontic study model: Digital caliper vs 3 dimensional digital intraoral scanner

Objectives: The interest on intraoral scanners for digital impressions has been growing and new devices are continuously introduced on the market. It is timely to verify whether the several scanners proposed for full-arch digital impressions have been tested under clinical conditions for validity, repeatability, reproducibility, as well as for time efficiency, and patient acceptance.
Materials and methods: 20 Pretreatment study models of patients were obtained. The sample size was divided into Group 1 (prime scan),15 subjects under Group 2 (3 shape) and Group 3 (digital caliper).linear measurements were assessed via transferring STL file to NEMOCEPH software. One Way ANOVA and significant results will be analysed for post hoc test 
Results: is that there was no statistically significant difference between scanners in mean values of intracanine width. (P = 0.6), Inter premolar width (P = 0.75), intra molar width (P = 0.37), Arch length (P = 0.85), Arch perimeter (P = 0.94), mesiodistal width (of 41) (P = 0.34) and cervicoincisal width (of 41) (P = 0.58) respectively.
Conclusion: Mean values of intercanine width, Interpremolar width, Intermolar width and arch perimeter were more when scanned using Prime Scanner. In addition, mean values of arch length and Cervicoinsical width (of 41) were more when scanned using Digital Caliper.