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Published on: September 8, 2023
Reliability and reproducibility of landmarks on three-dimensional soft-tissue cephalometrics using different
1Guangdong, People's Republic of China; and Cleveland, Ohio From the Department of Orthodontics, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology; and Case Western Reserve University.
The direct soft-tissue landmark placement method offers superior accuracy and reproducibility in 3D cephalometric analysis compared to indirect methods. This approach enhances facial aesthetic evaluations for clinical diagnosis.
Area of Science:
- Craniofacial analysis
- Medical imaging
- Aesthetic medicine
Background:
- Three-dimensional (3D) cephalometric analysis is crucial for facial aesthetics.
- Current methods involve in vivo optical surface imaging or computed tomographic (CT) models.
- Evaluating the reliability and reproducibility of soft-tissue landmark placement is essential.
Purpose of the Study:
- To determine the suitability of direct (in vivo) and indirect (CT model) landmark placement methods for soft-tissue evaluation.
- To assess the reproducibility and reliability of landmark placement using both methods in 3D cephalometric analysis.
Main Methods:
- Thirty-seven soft-tissue landmarks were assessed in 35 healthy volunteers.
- Direct and indirect placement methods were used by two operators, twice, at a 1-week interval.
- Landmark positions were measured in 3D coordinates, and errors were calculated using two-way random intraclass correlation coefficients.
Main Results:
- The direct method demonstrated higher reliability, with 86.5% of landmarks having an intraclass correlation coefficient (ICC) > 0.75 and 67.6% > 0.90.
- The indirect method showed lower reliability, with 75.7% of landmarks having an ICC > 0.75 and 43.2% > 0.90.
- The direct method yielded significantly smaller landmark placement errors and better reproducibility (p<0.05).
Conclusions:
- Direct soft-tissue landmark placement is more accurate than the indirect method for evaluating facial contours and texture.
- 3D cephalometric analysis using the direct method provides comprehensive evaluation of eye, lip, and lateral facial structures.
- This enhanced accuracy supports improved clinical diagnosis in facial aesthetics.
