Table 3. Multiple logistic regression showing associations between shape and other morphological features, according to Thomas and Kotze classification (n = 1160.
| Shape | Coef. | Std. Err. | 95% CI | p value |
|---|---|---|---|---|
| Curved | (base outcome) | |||
| Wavy | ||||
| Constant | -1.516 | 0.360 | [-2.221; -0.811] | <0.001** |
| Length | 0.188 | 0.030 | [0.129; 0.246] | <0.001** |
| Direction (Forward) | ||||
| Straight | -0.132 | 0.210 | [-0.544; 0.280] | 0.529 |
| Backward | -0.937 | 0.203 | [-1.335; -0.538] | <0.001** |
| Unification (Absent) | ||||
| Divergent | -0.601 | 0.231 | [-1.054; -0.148] | 0.009** |
| Convergent | -0.819 | 0.553 | [-1.904; 0.265] | 0.139 |
| Straight | ||||
| Constant | 0.398 | 0.357 | [-0.300; 1.097] | 0.264 |
| Length | -0.485 | 0.031 | [-0.108; 0.012] | 0.114 |
| Direction (Forward) | ||||
| Straight | 0.023 | 0.230 | [-0.427; 0.473] | 0.920 |
| Backward | -0.182 | 0.215 | [-0.603; 0.239] | 0.396 |
| Unification (Absent) | ||||
| Divergent | -0.286 | 0.215 | [-0.707; 0.135] | 0.183 |
| Convergent | -0.226 | 0.465 | [-1.137; 0.685] | 0.626 |
| LR Chi (2) (10) | 115.87 | |||
| Prob > Chi (2) | <0.001** | |||
| Pseudo R2 | 0.0456 | |||
Notes. Coef. = regression coefficient; Std. Err. = standard error;
LR Chi (2)(x) refers to the Likelihood ratio Chi-square test statistic and associated degrees of freedom.
(Base): refers to the base outcome all other categories are compared to
*Statistically significant at p ≤ 0.05; **Statistically significant at p < 0.01