Comparison of Digital Measurement versus Physical Model Measurement: An Analysis of Accuracy and Precision.

Objective: The objective of this study was to compare the accuracy and precision of digital model measurement to physical measurement of orthodontic models.

Methods: To assess accuracy, teeth were removed from a typodont and measured individually to obtain a gold standard measurement A stone model of the typodont was then measured n=75 times by both digital and physical measurement and these measurements were compared to the gold standard. To assess precision, patient
models (n=27) were measured five times each by each method and assessed via an intra-class correlation coefficient.
Results: The accuracy analysis suggested that measurements of individual tooth width, archlength, and crowding were all more significantly more accurate using the digital measurement technique regardless of whether trapezoidal or catenary measurements were used. The digital technique also showed a significant benefit in the analysis of precision, demonstrating a significant improvement in the intra-class correlation coefficient for each orthodontic measurement considered.
Conclusion: Digital model measurements have the potential to be more accurate and precise than physical model measurements.