Table 3.
Means and SDs for the depth of COS (mm), Wilcoxon signed-rank (within-group differences) and Mann–Whitney U (between-group differences) standardized test statistics and P values in the 3 studied groups
| T1 | T2 | T3 | T4 | T5 | T6 | T7 | T1–T7 | |
|---|---|---|---|---|---|---|---|---|
| Mean (SD) | Mean (SD) | Mean (SD) | Mean (SD) | Mean (SD) | Mean (SD) | Mean (SD) | Mean (SD) | |
| Group 1 (0.017 × 0.025 SS) | 5.11 (0.58) | 4.42 (0.49) | 3.83 (0.38) | 3.22 (0.39) | 2.97 (0.50) | 1.29 (0.44) | 0.67 (0.42) | 3.82 (0.70) |
| Group 2 (0.019 × 0.025 SS) | 5.59 (0.62) | 4.77 (0.56) | 4.12 (0.49) | 3.35 (0.61) | 2.82 (0.53) | 1.82 (0.50) | 1.12 (0.33) | 4.47 (0.51) |
| Group 3 (0.021 × 0.025 TMA) | 5.22 (0.73) | 4.61 (0.78) | 4.06 (0.54) | 3.78 (0.43) | 3.22 (0.43) | 2.39 (0.50) | 1.39 (0.52) | 3.85 (0.78) |
| Within-group differences in COS depth changes at different time points (mm) (related samples Wilcoxon signed-rank test) | ||||||||
| COS changes T1–T2 (standardized test statistics, P value) | COS changes T2–T3 (standardized test statistics, P value) | COS changes T3–T4 (standardized test statistics, P value) | COS changes T4–T5 (standardized test statistics, P value) | COS changes T5–T6 (standardized test statistics, P value) | COS changes T6–T7 (standardized test statistics, P value) | COS changes T1–T7 (standardized test statistics, P value) | ||
| Group 1 | (− 3.42, P < 0.001) | (− 3.21, P = 0.001) | (− 3.28, P = 0.001) | (− 2.25, P = 0.024) | (− 3.77, P < 0.001) | (− 3.94, P < 0.001) | (− 3.77, P < 0.001) | |
| Group 2 | (− 3.49, P < 0.001) | (− 3.46, P < 0.001) | (− 3.61, P < 0.001) | (− 3.00, P = 0.003) | (− 3.82, P < 0.001) | (− 3.42, P < 0.001) | (− 3.73, P < 0.001) | |
| Group 3 | (− 3.32, P < 0.001) | (− 2.33, P = 0.020) | (− 2.24, P = 0.025) | (− 3.16, P = 0.002) | (− 3.87, P < 0.001) | (− 3.90, P < 0.001) | (− 3.83, P < 0.001) | |
| Between-group differences (Mann–Whitney U test) | ||||||||
| COS changes T1–T2 (standardized test statistics, P value) | COS changes T2–T3 (standardized test statistics, P value) | COS changes T3–T4 (standardized test statistics, P value) | COS changes T4–T5 (standardized test statistics, P value) | COS changes T5–T6 (standardized test statistics, P value) | COS changes T6–T7 (standardized test statistics, P value) | COS changes T1–T7 (standardized test statistics, P value) | ||
| Groups 1 and 2 | (− 0.63, P = 0.590) | (− 0.34, P = 0.775) | (− 1.11, P = 0.369) | (− 1.63, P = 0.153) | (− 1.82, P = 0.207) | (1.31, P = 0.318) | (2.79, P = 0.009) | |
| Groups 1 and 3 | (− 0.33, P = 0.791) | (− 0.40, P = 0719) | (− 2.08, P = 0.068) | (− 1.83, P = 0.111) | (− 0.35, P = 0.815) | (− 1.46, P = 0.293) | (0.33, P = 0.767) | |
| Groups 2 and 3 | (− 0.98, P = 0.405) | (− 0.59, P = 0.599) | (− 2.84, P = 0.013) | (− 0.15, P = 0.909) | (− 1.59, P = 0.303) | (− 2.31, P = 0.057) | (2.53, P = 0.022) | |
T1, before inserting interventional arch wires with reverse COS; T2, 1 month; T3, 2 months; T4, 3 months; T5, 4 months; T6, 5 months; T7, 6 months after interventional arch wire insertion