This pilot study evaluated the repeatability and consistency of three methods—conventional, ultrasonic, and optical—for measuring mandibular functional parameters, with the goal of providing guidance for clinical implementation. Sagittal condylar inclination (SCI), Bennett angle (BA), and incisal and canine guidance were measured in 30 young adults (aged 19–27 years) using the three methods to assess intra-method repeatability, inter-method consistency, and differences in operating time (ΔOT). All three methods demonstrated good repeatability for functional parameters (ICC: 0.850–0.997). No significant differences were observed in SCI and BA values between bilateral measurements within the same participants across all methods (p > 0.05). Right SCI showed no significant differences among groups (p = 0.068), but left SCI was significantly larger in the optical group (p = 0.001). BA values were significantly higher in the conventional group than in the ultrasonic group (p = 0.044 left, p = 0.023 right); no significant difference was observed between the ultrasonic and optical groups (p = 0.808 left, p = 1.000 right). Comparisons of incisal and canine guidance inclinations revealed no significant differences among groups (p > 0.05). The ΔOT was significantly shorter in the optical group than in the conventional and ultrasonic groups (p < 0.0001). All three methods demonstrated excellent intra-method repeatability for measuring functional parameters in young adults but showed moderate inter-method consistency, particularly in SCI and BA values. For posterior and anterior rehabilitation in young adults, ultrasonic methods are preferred because of their superior consistency. When time efficiency is critical and anterior guidance is preserved, optical methods are acceptable with caution.
Zhu et al. (Mon,) studied this question.