pISSN 2234-7518
eISSN 2005-372X
eISSN 2005-372X
Definitions of the landmarks and variables of root inclination and root position for the dentition relative to the basal bone region
| Landmark/variable | Definition |
|---|---|
| ra point | Root apex point, the most apical point of teeth |
| ra’ point | The projection point of the ra point to the basal bone plane |
| rc point | Root center point, the cemento-enamel junction for single-root teeth or the root furcation for multi-root teeth |
| Root axis vector | The value of the root axis vector was obtained from ra point to rc point |
| Root inclination | |
| Single-root teeth | The angle between the root axis vector and basal bone plane. The value of the root axis vector was obtained from the ra point to the cemento-enamel junction |
| Multi-root teeth | The angle between the root axis vector and basal bone plane. The value of the root axis vector was obtained from the average value of ra points to the root furcation |
| Root position | |
| DE | Distances from ra’ point to the external boundary of basal bone region |
| DI | Distances from ra’ point to the internal boundary of basal bone region |
| Ratio | DE/DI, indicates the relative root position of each tooth |
| Log Ratio | The value of Ratio after logarithmically transformation. The range of Log Ratio is symmetric, and the midpoint is 0. If the value of Log Ratio was positive, the root apex was closer to the inner boundary of the basal bone. If the value of Log Ratio was negative, the root apex was closer to the external boundary of the basal bone |