Table 1.
Definitions of the chin and the symphysis measurements.
| Measurement | Definition | |
|---|---|---|
| Chin | Height (mm) | The distance between the most posterior midline point in the concavity of the mandibular symphysis (B point) and the menton |
| Thickness(mm) | The maximum thickness of the chin, measured as the length of the perpendicular line from pogonion to the chin height line | |
| CSA (mm2) | The portion of the symphysis CSA that is located anterior to the chin height line | |
| Width (mm) | The distance between the right and left mental tubercles | |
| Symphysis | Height (mm) | The distance between the most superior point on the alveolar bone and menton |
| Thickness (mm) | The distance between the pogonion and the most posterior point on the symphysis | |
| CSA (mm2) | The total CSA of the symphysis in the midsagittal plane | |
| Inclination (°) | Inclination of the symphysis relative to the MP: the angle (α angle) created between the line passing from the infradentale (the midline point at the superior tip of the septum between the mandibular central incisors) to the gnathion (Id-Gn line), and the line passing from gonion to gnathion [27] | |
| Orientation (°) | Inclination of the symphysis relative to the FH plane: the angle (β angle) measured at the cross-point between the Id-Gn line and the FH plane (the porion-orbitale line) | |
Note: CSA- cross-sectional area; MP-mandibular plane; Id-infradentale; Gn-gnathion; FH- Frankfort horizontal.