Table 3.
Changes in the anteroposterior and vertical dentoskeletal variables after rapid maxillary expansion (RME)
| Dentoskeletal variables | T-RME | H-RME | Intergroup p value‡ | ||||||
|---|---|---|---|---|---|---|---|---|---|
| T1 | T2 | Change | Intragroup p value† | T1 | T2 | Change | Intragroup p value† | ||
| Skeletal variables | |||||||||
| SNA (°) | 78.80 ± 3.66 | 79.44 ± 3.22 | 0.64 ± 1.39 | 0.073 | 79.92 ± 3.04 | 80.44 ± 3.25 | 0.52 ± 0.98 | 0.021 | 0.960 |
| SNB (°) | 77.51 ± 3.58 | 76.86 ± 3.73 | − 0.65 ± 0.97 | 0.014 | 78.07 ± 4.94 | 77.56 ± 4.69 | − 0.51 ± 1.28 | 0.060 | 0.890 |
| ANB (°) | 1.29 ± 2.11 | 2.58 ± 2.22 | 1.29 ± 1.42 | < 0.001 | 1.85 ± 3.48 | 2.88 ± 3.10 | 1.04 ± 0.99 | 0.001 | 0.950 |
| A to N perp (mm) | − 1.90 ± 2.95 | − 1.37 ± 2.63 | 0.53 ± 1.37 | 0.052 | − 1.43 ± 3.70 | − 0.09 ± 3.98 | 1.34 ± 1.39 | 0.001 | 0.005 |
| Pog to N perp (mm) | − 6.30 ± 6.66 | − 8.43 ± 7.13 | − 2.13 ± 1.76 | < 0.001 | − 6.51 ± 10.26 | − 6.33 ± 10.38 | 0.17 ± 2.33 | 0.821 | 0.002 |
| FMA (°) | 29.96 ± 4.28 | 31.24 ± 4.49 | 1.28 ± 1.03 | < 0.001 | 32.01 ± 6.96 | 31.91 ± 7.16 | − 0.10 ± 1.29 | 0.715 | 0.001 |
| LAFH (mm) | 76.92 ± 7.12 | 78.56 ± 6.91 | 1.64 ± 1.18 | < 0.001 | 78.51 ± 5.21 | 78.29 ± 5.23 | − 0.22 ± 2.18 | 0.889 | < 0.001 |
| Palatal plane angle (°) | 1.33 ± 2.98 | 1.25 ± 2.77 | − 0.08 ± 1.17 | 0.821 | 1.37 ± 4.12 | 0.79 ± 3.93 | − 0.58 ± 1.27 | 0.063 | 0.170 |
| Dentoalveolar variables | |||||||||
| U1 to SN (°) | 103.19 ± 6.43 | 100.45 ± 6.51 | − 2.74 ± 2.37 | < 0.001 | 107.25 ± 7.59 | 103.21 ± 6.93 | − 4.03 ± 3.41 | < 0.001 | 0.163 |
| U1 to FH (°) | 112.76 ± 6.22 | 109.88 ± 6.47 | − 2.88 ± 2.07 | < 0.001 | 116.15 ± 7.88 | 112.70 ± 7.24 | − 3.46 ± 3.35 | 0.001 | 0.505 |
| U1 IE to FH (mm) | 61.42 ± 3.57 | 62.50 ± 3.73 | 1.08 ± 0.85 | < 0.001 | 62.10 ± 3.79 | 62.59 ± 3.77 | 0.49 ± 2.07 | 0.035 | 0.333 |
| U6 MBC to FH (mm) | 54.85 ± 3.51 | 55.43 ± 3.76 | 0.58 ± 1.16 | 0.046 | 55.79 ± 2.85 | 55.74 ± 3.22 | − 0.05 ± 1.74 | 0.664 | 0.314 |
| Overjet (mm) | 2.76 ± 2.72 | 2.94 ± 2.52 | 0.18 ± 1.13 | 0.715 | 3.27 ± 3.78 | 3.66 ± 3.32 | 0.39 ± 1.24 | 0.085 | 0.285 |
| Overbite (mm) | 0.44 ± 2.74 | − 0.14 ± 2.88 | − 0.58 ± 1.06 | 0.033 | 0.02 ± 3.95 | 0.14 ± 3.67 | 0.13 ± 1.19 | 0.211 | 0.019 |
Data are presented as mean ± standard deviation
T-RME, the group who received RME procedure with the conventional tooth-born expander; H-RME, the group underwent RME using the tooth-bone-borne hybrid expander; T1, pretreatment; T2, after RME (at least 6 weeks after fixation of the expander); Change, change in each variable after RME; SNA, sella–nasion-A point; SNB, sella–nasion-B point; ANB, A point-nasion-B point; A to N perp, A point to nasion perpendicular; Pog to N perp, pogonion to nasion perpendicular; FMA, Frankfort-mandibular plane angle; LAFH, lower anterior facial height; U1 to SN, maxillary incisor to sella–nasion plane angle; U1 to FH, maxillary incisor to Frankfort horizontal plane angle; U1 IE to FH, maxillary incisal edge to Frankfort horizontal plane; U6 MBC to FH, maxillary first molar mesiobuccal cusp to Frankfort horizontal plane
†The Wilcoxon signed-rank test was used to analyse the significance of changes in the variables within a group
‡The Mann–Whitney U test was used to analyse the significance of differences in changes between the groups