Table 3 Mann–Whitney U test comparison of percentage of external root resorption (ERR) between the maxilla and the mandible classified by age group and teeth type (anterior and posterior teeth)
|  | Sample Size | ERR, % Median (P25, P75) | Mann–Whitney U test | ||
|---|---|---|---|---|---|
Maxillary | Mandible | Maxillary | Mandible | P Value | |
Group I | |||||
Anterior teeth | 106 | 107 | 6.75 (3.10, 11.50) | 6.77(2.70, 14.18) | 0.686 |
Posterior teeth | 120 | 126 | 0.90 (-2.71, 7.41) | 2.85 (-0.79,8.56) | 0.040* |
Group II | |||||
Anterior teeth | 106 | 106 | 7.14 (3.23, 14.32) | 6.24 (2.43,17.77) | 0.851 |
Posterior teeth | 116 | 128 | 3.17 (0.05, 10.34) | 3.99 (0.35, 9.98) | 0.625 |