Table 2.
Descriptive statistics of the en-masse retraction rate (mm/month) as well as the P values of significance tests.
| Time | FCG | TCG | FCG vs TCG mean difference (95% CI) | P value† | ||||
|---|---|---|---|---|---|---|---|---|
| n | Mean | SD | n | Mean | SD | |||
| Upper central incisors retraction rate | ||||||||
| T0-T1 | 18 | 1.60 | 0.14 | 18 | 1.82 | 0.18 | −0.23 (−0.33, −0.12) | <0.001∗ |
| T1-T2 | 18 | 1.42 | 0.10 | 18 | 1.66 | 0.15 | −0.24 (−0.33, −0.16) | <0.001∗ |
| T2-T3 | 18 | 1.22 | 0.10 | 18 | 1.39 | 0.18 | −0.17 (−0.27, −0.07) | 0.001∗ |
| T3-T4 | 15 | 1.08 | 0.08 | 15 | 1.14 | 0.18 | −0.06 (−0.16, 0.04) | 0.244 |
| T4-T5 | 9 | 0.98 | 0.12 | 6 | 0.89 | 0.11 | 0.09 (−0.04, 0.22) | 0.148 |
| T0-TF | 18 | 6.18 | 0.25 | 18 | 6.84 | 0.31 | −0.65 (−0.84, −0.46) | <0.001∗ |
|
| ||||||||
| Upper canine retraction rate | ||||||||
| T0-T1 | 18 | 1.57 | 0.19 | 18 | 1.80 | 0.18 | −0.23 (−0.35, −0.10) | <0.001∗ |
| T1-T2 | 18 | 1.41 | 0.10 | 18 | 1.63 | 0.15 | −0.22 (−0.31, −0.14) | <0.001∗ |
| T2-T3 | 18 | 1.21 | 0.10 | 18 | 1.38 | 0.18 | −0.17 (−0.27, −0.08) | 0.001∗ |
| T3-T4 | 15 | 1.07 | 0.09 | 15 | 1.09 | 0.22 | −0.02 (−0.15, 0.11) | 0.742 |
| T4-T5 | 9 | 0.98 | 0.12 | 6 | 0.86 | 0.14 | 0.11 (−0.03, 0.26) | 0.115 |
| T0-TF | 18 | 6.09 | 0.37 | 18 | 6.65 | 0.40 | −0.55 (−0.82, −0.29) | <0.001∗ |
†Two-sample t-test. ∗Employing Bonferroni's correction for multiplicity, statistical significance was set at P < 0.008 (alfa: 0.05/6 = 0.008); FCG: flapless corticotomy group; TCG: traditional corticotomy group; SD: standard deviation; CI: confidence interval; the TCG values were subtracted from the FCG values.