Factors affecting the accuracy of intraoral scanning in digital morphometric assessment of oral soft tissues

Abstract

Background. Accurate assessment of oral soft tissues is an important task in modern dentistry, particularly in implantology and prosthetic practice. Conventional methods for measuring gingival thickness are invasive and operator-dependent, which limits their use for longitudinal monitoring. Objective. To evaluate the influence of intraoral scanning factors on the accuracy of digital morphometric measurements of oral soft tissues. Materials and methods. The study included 36 patients. Gingival thickness measurements were performed using five intraoral scanners, three operators, and three scanning strategies (layering, linear, and random). Digital measurements were compared with transgingival probing. Statistical analysis included the Shapiro – Wilk test, Kruskal – Wallis test, multifactor analysis of variance, intraclass correlation coefficient (ICC), and Bland – Altman analysis. Results. Scanning strategy had a statistically significant effect on measurement outcomes (p < 0.001). The lowest variability was observed with the layering strategy, whereas the highest variability was associated with random scanning. Differences between scanners were also statistically significant (p = 0.030), but the maximum inter-device difference was only 0.16 mm. No significant inter-operator differences were found (p > 0.05). High reproducibility of the method was confirmed (ICC = 0.992). Agreement with transgingival probing was considered acceptable. Conclusion. Scanning strategy has a greater impact on the accuracy of digital morphometric measurements than the type of intraoral scanner. The proposed method is reproducible and suitable for non-invasive soft tissue assessment.