Table 3 Distribution of the root length reduction during orthodontic treatment: post-treatment RCR relative to pre-treatment RCR (rRCR), absolute (n) and relative (%) frequencies (n = 1600): rRCR < 80 means a reduction over 20% of pre-treatment root length
From: Apical root resorption during orthodontic treatment with aligners? A retrospective radiometric study
rRCR | Frequency | Percent |
|---|---|---|
| Â | (n) | (%) |
rRCR < 80 | 101 | 6.31 |
80 ≤ rRCR < 90 | 191 | 11.94 |
90 ≤ rRCR < 100 | 444 | 27.75 |
rRCR ≥ 100 | 864 | 54.00 |