Reproducibility of Digital Measurements on Soft and Hard Tissue

The aim of this proof-of-principle study was to investigate the reproducibility of digital hard- and soft-tissue measurements obtained using an intraoral scanner.

Two consecutive digital scans of the maxilla and mandible of 20 subjects aged 18-58 years were captured with an intraoral scanner. Afterwards, the double scans of each subject were virtually matched by three different methods using a dental software program. Linear distances between defined hard- and soft-tissue points on the intraoral scans were measured for each individual. To assess the reproducibility of the measurements for each matching method, the corresponding linear distances of the first and second scans were compared using a paired t-test (p 0.05). ANOVA (p 0.05) was used for comparison of the three matching methods.

For both hard and soft tissue, the measured linear distances between the first and second scans did not differ statistically significantly. Furthermore, there were no statistically significant differences between the three matching methods for soft (p = 0.196) and hard (p = 0.963) tissue.

Digital measurements of hard and soft tissue are reproducible using intraoral scans. Furthermore, all three matching methods are suitable for the superimposition of scans. However, possible inaccuracies may depend on the experience of the practitioner, the technical limitations of the systems used, and patient-related factors.