Comparisons of gender and age at debonding, molar relationships and ANB° before orthodontic treatment, and changes in arch dimensions with active orthodontic treatment between the groups_
| Group 1 | Group 2 | Group 3 | Group 4 | p-value | ||
|---|---|---|---|---|---|---|
| N (%), median (min, max) or mean ± SD) | N (%), median (min, max) or mean ± SD) | N (%), median (min, max) or mean ± SD) | N (%), median (min, max) or mean ± SD) | |||
| Gender | Female | 12 (100%) | 5 (41.7%) | 11 (84.6%) | 10 (66.7%) | 0.009 *,a |
| Male | 0 (0%) | 7 (58.3%) | 2 (15.4%) | 5 (33.3%) | ||
| Molar relationship | Class I | 9 (75%) | 9 (75%) | 8 (61.5%) | 7 (46.7%) | 0.198 a |
| End-to-end | 3 (25%) | 2 (16.7%) | 3 (23.1%) | 8 (53.3%) | ||
| Class II | 0 (0%) | 1 (8.3%) | 2 (15.4%) | 0 (0%) | ||
| Age (years) | 16.15 (14.1, 19.9) | 16.1 (14.1, 18) | 17 (15.3, 19.1) | 17.25 (14, 23) | 0.162 b | |
| ANB° | 3.15° (0.7°, 4.2°) | 4.9° (1.6, 5.7) | 3.8 (1, 5.1) | 3 (0.9, 7) | 0.113 b | |
| Little (mm) (T1-T0) | Maxilla | -7.86 (-14.98,-4.62) | -8.97 (-14.6,-2.9) | -8.05 (-13.14,-3.09) | -8.21 (-16.8, -6.13) | 0.885 b |
| Mandible | -6.58±2.43 | -6.81±3.08 | -8.25±3.40 | -7.40±3.08 | 0.521 c | |
| Intercanine width (mm) (T1-T0) | Maxilla | 0.52 (-4.13, 5.33) | 0.51 (-4.42,6.98) | 1.54 (-1.75, 2.74) | 0.78 (-2.45, 4.27) | 0.957 b |
| Mandible | 0.44±1.20 | 1.07±1.67 | 1.11±1.66 | 0.97±1.21 | 0.640 c | |
| Intermolar width (mm) (T1-T0) | Maxilla | 0.18 (-2.73, 4.6) | 1.73 (-1.5, 4.6) | 0.99 (-0.71, 6.32) | 0.12 (-1.01, 5.4) | 0.175 b |
| Mandible | -0.01±1.60 | 1.96±1.65 | 0.24±1.83 | 1.32±2.44 | 0.051 c | |
| Arch length (mm) (T1-T0) | Maxilla | 2.08±2.10 | 1.90±2.65 | 2.12±3.16 | 2.31±2.96 | 0.986 c |
| Mandible | 2.64±1.89 | 2.81±4.71 | 2.14±3.64 | 3.61±3.26 | 0.732 c | |
| Overjet (mm) (T1-T0) | -0.73±1.24 | -0.63±1.24 | -0.27±1.35 | -1.03±1.12 | 0.456 c | |
| Overbite (mm) (T1-T0) | -0.66±1.13 | -1.53±1.27 | -1.00±1.38 | -1.29±1.27 | 0.372 c |
Intragroup and intergroup arch measurement changes occurred from debonding (T1) to 12th month (T3), and from sixth (T2) to 12th month (T3 of retention, and their significances_
| Maxilla | Mandible | Inter-arch | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Little (mm) (mean±SD) | Intercanine width (mm) (mean±SD) | Intermolar width (mm) (mean±SD) | Arch length (mm) (mean±SD) | Little (mm) (mean±SD) | Intercanine width (mm) (mean±SD) | Intermolar width (mm) (mean±SD) | Arch Length (mm) (mean±SD) | Overjet (mm) (mean±SD) | Overbite (mm) (mean±SD) | ||
| Group 1 (N=12) | T3-T2 | 0.30±0.27 | 0.03±0.30 | 0.01±0.18 | 0.03±0.43 | 0.31±0.45 | -0.05±0.20 | 0.04±0.11 | 0.17±0.84 | -0.18±0.49 | 0.02±0.41 |
| P | 0.172 a | 1.000 a | 1.000 a | 1.000 a | 0.212 a | 1.000 a | 1.000 a | 1.000 a | 0.482 a | 1.000 a | |
| T3-T1 | 1.02±0.84 | 0.91±0.64 | 0.71±0.61 | 0.15±0.69 | 1.10±0.92 | -0.14±0.51 | 0.45±0.58 | -0.18±0.95 | 0.08±0.63 | 0.35±0.47 | |
| P | <0.001 ****,a | 1.000 a | 0.001 ***,a | 1.000 a | <0.001 ****,a | 1.000 a | 0.347 a | 1.000 a | 1.000 a | 0.121 a | |
| Group 2 (N=12) | T3-T2 | 0.41±0.43 | -0.38±0.58 | 0.03±0.46 | -0.12±0.5 | 0.80±0.58 | -0.08±0.31 | 0.08±0.40 | -0.25±0.62 | -0.10±0.42 | 0.14±0.39 |
| P | 0.028 *,a | 0.178 a | 1.000 a | 1.000 a | <0.001 ****,a | 1.000 a | 1.000 a | 0.890 a | 1.000 a | 0.884 a | |
| T3-T1 | 0.81±0.76 | -0.17±0.84 | 0.25±0.73 | -0.11±1.05 | 1.17±0.79 | -0.11±0.61 | 0.09±0.79 | -0.30±0.82 | -0.36±0.90 | 0.23±0.58 | |
| P | 0.001 ***,a | 1.000 a | 0.569 a | 1.000 a | <0.001 ****,a | 1.000 a | 1.000 a | 1.000 a | 0.213 a | 0.557 a | |
| Group 3 (N=13) | T3-T2 | 0.23±0.66 | 0.39±0.94 | 0.51±1.00 | 0.44±0.88 | 0.27±0.37 | -0.17±0.59 | 0.46±0.95 | 0.11±0.95 | -0.30±0.54 | -0.24±0.50 |
| P | 0.371 a | 0.134 a | 0.010 **,a | 0.024 *,a | 0.287 a | 0.409 a | 0.027 *,a | 1.000 a | 0.048 *,a | 0.172 a | |
| T3-T1 | 0.62±0.55 | 0.21±0.60 | 0.36±0.71 | 0.44±1.69 | 0.91±0.66 | 0.19±0.76 | 0.82±1.42 | 0.60±2.45 | -0.32±0.53 | 0.15±0.60 | |
| P | 0.010 **,a | 0.919 a | 0.165 | 0.579 | 0.001 ***,a | 0.805 a | 0.011 *,a | 0.519 a | 0.289 | 1.000 a | |
| Group 4 (N=15) | T3-T2 | 0.34±0.62 | 0.36±0.71 | 0.14±0.42 | 0.00±0.37 | 0.59±0.77 | 0.06±0.42 | 0.34±0.62 | -0.05±0.83 | 0.12±0.29 | -0.04±0.45 |
| P | 0.048*,a | 1.000 a | 1.000 a | 1.000 a | 0.001 ***,a | 1.000 a | 0.120 a | 1.000 a | 0.936 a | 1.000 a | |
| T3-T1 | 0.76±0.73 | -0.03±0.80 | 0.18±0.55 | 0.20±1.09 | 1.10±0.91 | 0.07±0.50 | 0.25±0.86 | -0.25±1.38 | 0.19±0.59 | 0.22±0.64 | |
| P | 0.001 ***,a | 1.000 a | 0.890 a | 1.000 a | <0.001 ****,a | 1.000 a | 0.945 a | 1.000 a | 0.852 a | 0.453 a | |
| Intergroup comparison (p-value) | T3-T2 | 0.897 b | 0.016 *,b (2-3; p=0.008 ** ) | 0.286 b | 0.306 d | 0.119 b | 0.651 b | 0.298 b | 0.494 b | 0.092 c | 0.206 c |
| T3-T1 | 0.604 c | 0.599 c | 0.196 c | 0.399 b | 0.875 c | 0.481 c | 0.575 b | 0.727 b | 0.076 b | 0.527 b | |
Arch measurements at debonding (T1), after six month full-time retention (T2), measurement changes from T1 to T2, comparisons of the changes between Hawley and vacuum-formed retainer groups_
| HAWLEY (N=26) | P | VACUUM-FORMED RETAINER (N=32) | P | Intergroup comparison | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| T1 Mean ± SD or median (min, max) | T2 Mean ± SD or median (min, max) | T2-T1 Mean ± SD or median (min, max) | T1 Mean ± SD or median (min, max) | T2 Mean ± SD or median (min, max) | T2-T1 Mean ± SD or median (min, max) | |||||
| Maxilla | Little (mm) | 0 (0,0) | 0.44 (0, 2.08) | 0.44 (0, 2.08) | <0.001 ****,a | 0 (0,0) | 0.05 (0, 2.3) | 0.05 (0, 2.3) | <0.001 ****,a | 0.225 c |
| Intercanine width (mm) | 36±2.17 | 36.16±2.14 | 0.17±0.72 | 0.253 b | 35.07 (31.9, 38.08) | 34.94 (31.56, 38.86) | 0 (-2.78, 0.78) | 0.414 a | 0.081 c | |
| Intermolar width (mm) | 51.29 (43.69, 59.20) | 51.83 (45.10, 59.28) | 0.32 (-0.57, 1.82) | <0.001 ****,a | 51.12 (45.75, 58.06) | 51.31 (44.82, 58.06) | 0 (-1.65, 1.25) | 0.679 a | <0.001 ****,c | |
| Arch Length (mm) | 71.83±4.00 | 71.91±3.96 | 0.77±0.90 | 0.663 b | 70.00 (62.76, 78.30) | 70.18 (62.8, 77.8) | 0.01 (-1.8, 3.26) | 0.940 a | 0.969 c | |
| Mandible | Little (mm) | 0 (0,0) | 0.46 (0, 2.64) | 0.46 (0, 2.64) | <0.001 ****,a | 0 (0, 1.36) | 0.39 (0, 1.79) | 0.37 (0, 1.61) | <0.001 ****,a | 0.703 c |
| Intercanine width (mm) | 27.53±1.76 | 27.52±1.72 | -0.02±0.52 | 0.884 b | 26.85±1.41 | 27.02±1.42 | 0.16±0.43 | 0.039 *,b | 0.156 d | |
| Intermolar width (mm) | 44.64±2.69 | 44.88±2.62 | 0.24±0.61 | 0.057 b | 44.76 (38.45, 52.05) | 44.62 (38.88, 52.05) | 0.04 (-1.11, 1.90) | 0.204 a | 0.334 c | |
| Arch Length (mm) | 61.93±3.61 | 61.70±3.83 | -0.23±0.90 | 0.204 b | 61.29 (52.88, 66.74) | 60.77 (52.88, 66.17) | 0.10 (-1.74, 5.79) | 0.926 a | 0.260 c | |
| Inter-arch | Overjet (mm) | 2.27±0.88 | 2.30±0.73 | 0.04±0.63 | 0.776 b | 2.16±0.72 | 2.18±0.72 | 0.02±0.48 | 0.825 b | 0.910 d |
| Overbite (mm) | 2.36±0.73 | 2.59±0.76 | 0.23±0.56 | 0.047 *,b | 2.48±0.71 | 2.79±0.65 | 0.31±0.49 | 0.001 ***,b | 0.571 d | |