Validity and reliability of digital model measurements: A digital stereomicroscopic study

The purpose of this study was to evaluate the validity and reliability of orthodontic measurements made on digital models created with Hirox digital microscope (HDM). The data sources were plaster dental models from the archives of School of Dental Sciences, Universiti Sains Malaysia. A total of 11 dental models with 396 variables were measured using the plaster dental casts, and Hirox digital models were created. The study inclusion and exclusion criteria were followed. Two investigators (A and B) carried out the measurements of the selected dental casts using a digital caliper (DC) and the HDM. Dental plaster models were scanned using the HDM for the fabrication of the Hirox digital models. The tooth size and arch width were measured by DC and HDM. The validity of the digital measurements for examiners A and B the ICC coefficients were statistically significant (p<0.001), and the values of coefficient were in the range of strong correlation. The ICC coefficient values for inter-examiner A and B were all in the range of strong correlation for both tooth size and arch width variables in which the reliability coefficient values were comparable between digital measurements using HDM and measurements using DC. All ICC coefficient values were statistically significant (p<0.001). The results show that linear measurements of dental casts using a digital microscope are valid and reliable.