Background
Aim of the study
Methods
Trial design
Ethics approval and consent to participate
Eligibility criteria
Intervention
Outcomes
Skeletal measurements | |
SNA (°) | The angle between 3-point landmarks: S, N, and A point |
SNB (°) | Sella-nasion to B point angle |
ANB (°) | The angle between 3-point landmarks: A, N, B |
Vertical skeletal measurements | |
LAFH (mm.) | Lower anterior facial height (mm): distance between ANS and menton |
PFH (mm.) | Posterior facial height (mm): distance between S and Gonion |
Dental measurements | |
U1-SN (°) | The angle measured between the long axis of the upper central incisor and the SN plane |
U3 angle (°) | The angle measured between the long axis of the canine (cusp tip to root apex) and the Sella-Nasion line |
U6 angle (°) | The angle measured between the long axis of the mesiobuccal cusp to the mesiobuccal root apex of the maxillary first molar and the Sella- Nasion line |
L6 angle (°) | The angle measured between the long axis of the mesiobuccal cusp to the mesial root apex of the mandibular first molar and the Sella-Nasion line |
IMPA (°) | The angle measured between the long axis of the mandibular central incisor and the Gonion-Menton line |
Interincisal angle: IIA (°) | The angle measured between the long axis of the upper and lower central incisor |
Dental Linear measurements | |
U3 VP (mm.) | The vertical distance from the horizontal plane (SN-7) to the upper canine cusp tip |
U6 VP (mm.) | The vertical distance from the horizontal plane (SN-7) to mesiobuccal cusp tip of the upper fisrt molar |
L6m VP (mm.) | The vertical distance from the horizontal plane (SN-7) to the mesiobuccal cusp tip of the lower fisrt molar |
L6d VP (mm.) | The vertical distance from the horizontal plane (SN-7) to the distobuccal cusp tip of the lower fisrt molar |
L6 AP position (mm.) | The horizontal distance from the mesiobuccal cusp tip of the lower fisrt molar to the vertical plane (perpendicular to the horizontal plane (SN-7) from S point) |
cc | cusp tip of the maxillary canine. |
mb | mesiobuccal cusp tip of the maxillary first molar. |
mp | mesiopalatal cusp tip of the maxillary first molar. |
db | distobuccal cusp tip of the maxillary first molar. |
dp | distopalatal cusp tip of the maxillary first molar. |
CMR | the point that bisects the mb- dp line with mp-db line on the maxillary right first molar. |
CML | the point that bisects the mb-dp line with mp-db line on the maxillary left first molar. |
Model angular measurements: (Fig. 3B) | |
MV- RU3 | The angle between MV (A vertical reference line drawn through the median palatine suture from the incisive papilla) and the right canine cusp tip. |
MV- LU3 | The angle between MV and the left canine cusp tip. |
MV- U3 | Mean of MV-R3 and MV- L3 |
MV-RU6: | The angle between MV and mb-dp line of the right first molar. |
MV-LU6: | The angle between MV and mb-dp line of the left first molar. |
MV-U6: | Mean of MV-R6 and MV-L6 |
Model linear measurements: (Fig. 3C) | |
MH- RU3 | The perpendicular distance between upper right canine cusp tip and MH line (the horizontal reference line passing through the left third rugae and perpendicular to MV) |
MH- LU3 | The perpendicular distance between upper left canine cusp tip and MH line |
MH- U3 | Mean of MH-RU3 and MH- LU3 |
MH- RU6 | The perpendicular distance between CMR and MH line |
MH-LU6 | The perpendicular distance between CML and MH line |
MH-U6 | Mean of MH- RU6 and MH- LU6 |
Arch width: (Fig. 3D) | |
Inter-canine width (ICW) | distance between cc points of both right and left canines. |
Inter-molar width (IMW) | distance between CMR and CML points. |
Overjet (mm): Fig. 3E | measured from the labial surface of lower incisors to the incisal edge of upper incisors. |
Overbite (mm): Fig. 3F | The amount of vertical ovelap of lower incisors. |
Sample size calculation
Randomization
Masking
Statistical analysis
Results
Participant flow
Baseline data
Characteristic | Group | Test of significance | ||
---|---|---|---|---|
IZCG (n = 16) | EXG (n = 16) | |||
Categorical characteristic | N (%) | N (%) | χ2 | p-value |
Sex | .582 | .446* | ||
Male | 4 (25%) | 6 (37.5%) | ||
Female | 12 (75%) | 10 (62.5%) | ||
Number of de-bonded CMAs | - | .838** | ||
0 | 11 (68.8%) | 13 (81.3%) | ||
1 | 3 (18.8%) | 1 (6.3%) | ||
2 | 2 (12.5%) | 2 (12.5%) | ||
Failure of anchorage device | - | 1.000*** | ||
0 (no failure) | 13 (81.3%) | 14 (87.5%) | ||
1 (failure once) | 3 (18.8%) | 2 (12.5%) | ||
Numerical characteristic | Mean ± SD | Mean ± SD | t [30] | p-value |
Age (years) | 14.5 ± 1.4 | 13.8 ± 1.1 | -1.563 | .129$ |
Treatment duration (months) | 6.3 ± 2.1 | 5.9 ± 2.8 | -0.463 | .647$ |
Outcomes measurements
Treatment duration
Skeletal and dental measurements
Characteristic | Pre | Post | Difference | 95% CI | p-value | Cohen’s d | |
---|---|---|---|---|---|---|---|
Lower bound | Upper bound | ||||||
SNA (°) | 83.8 ± 3.9 | 83.8 ± 4 | 0 ± 0.3 | -0.2 | 0.2 | .949 | 0.016 |
SNB (°) | 78.5 ± 4 | 78.7 ± 4.2 | 0.2 ± 0.8 | -0.2 | 0.6 | .329 | 0.252 |
ANB (°) | 5.2 ± 1.4 | 5.1 ± 1.7 | -0.1 ± 0.7 | -0.5 | 0.2 | .452 | 0.193 |
LAFH (mm) | 61.1 ± 4.2 | 61.1 ± 4.2 | 0 ± 1.4 | -0.7 | 0.8 | .931 | 0.022 |
PFH (mm) | 71.3 ± 6.2 | 71.4 ± 6.3 | 0.1 ± 1 | -0.5 | 0.6 | .743 | 0.083 |
U1-SN (°) | 104.2 ± 11.2 | 100.4 ± 11.3 | -3.8 ± 2 | -4.9 | -2.8 | < .001 | 1.931 |
U3 ANGLE (°) | 97.6 ± 7.2 | 90.8 ± 8.2 | -6.8 ± 4.9 | -9.4 | -4.1 | < .001 | 1.387 |
U6 ANGLE (°) | 75.1 ± 8.1 | 69.3 ± 9.5 | -5.8 ± 4.2 | -8.1 | -3.5 | < .001 | 1.370 |
L6 ANGLE (°) | 59.8 ± 8.6 | 60.1 ± 8.4 | 0.4 ± 0.8 | 0 | 0.8 | .071 | 0.485 |
IMPA (°) | 95.7 ± 5.8 | 95.5 ± 6.1 | -0.2 ± 0.7 | -0.6 | 0.2 | .246 | 0.302 |
IIA (°) | 127.5 ± 11.5 | 131 ± 11.6 | 3.4 ± 2.6 | 2.1 | 4.8 | < .001 | 1.330 |
U3 VP (mm) | 64.8 ± 3.2 | 64.3 ± 3.3 | -0.5 ± 0.8 | -0.9 | -0.1 | .030 | 0.598 |
U6 VP (mm) | 61.4 ± 2.5 | 59.7 ± 2.9 | -1.7 ± 1.3 | -2.4 | -1.1 | < .001 | 1.365 |
L6m VP (mm) | 63 ± 2.9 | 63 ± 2.7 | 0 ± 0.5 | -0.2 | 0.3 | .839 | 0.052 |
L6d VP (mm) | 61.3 ± 3 | 61.2 ± 2.9 | 0 ± 0.5 | -0.3 | 0.2 | .634 | 0.121 |
L6 AP (mm) | 39.3 ± 6.5 | 39.2 ± 6.5 | 0 ± 0.2 | -0.2 | 0.1 | .267 | 0.288 |
Model measurements | |||||||
MV- U3 | 36.8 ± 5.4 | 50.3 ± 6.6 | 13.5 ± 5.9 | 10.4 | 16.7 | < .001 | 2.287 |
MV- U6 | 31.2 ± 6.2 | 46.9 ± 7.1 | 15.6 ± 7 | 11.9 | 19.3 | < .001 | 2.233 |
MH- U3 | 12 ± 2.5 | 8.9 ± 2.3 | -3.1 ± 0.9 | -3.6 | -2.6 | < .001 | 3.453 |
MH- U6 | 12.1 ± 2.2 | 15.4 ± 1.9 | 3.2 ± 1.2 | 2.6 | 3.9 | < .001 | 2.691 |
ICW | 33.9 ± 2.4 | 44.6 ± 2.8 | 10.7 ± 3 | 9.1 | 12.3 | < .001 | 3.584 |
IMW | 45.4 ± 2.9 | 46.3 ± 3.1 | 0.9 ± 0.8 | 0.5 | 1.4 | < .001 | 1.123 |
OJ | 4.9 ± 1.7 | 3.3 ± 1.5 | -1.6 ± 1 | -2.1 | -1 | < .001 | 1.525 |
OB | 3 ± 1.7 | 3 ± 1.7 | 0 ± 0.8 | -0.4 | 0.4 | .975 | 0.008 |
Characteristic | Pre | Post | Difference | 95% CI | p-value | Cohen’s d | |
---|---|---|---|---|---|---|---|
Lower bound | Upper bound | ||||||
SNA (°) | 81.4 ± 3.2 | 80.9 ± 3 | -0.5 ± 0.7 | -0.9 | -0.1 | .012 | 0.710 |
SNB (°) | 75.4 ± 2.6 | 76.3 ± 2.6 | 0.9 ± 0.5 | 0.6 | 1.1 | < .001 | 1.756 |
ANB (°) | 5.9 ± 1.5 | 4.6 ± 1.3 | -1.3 ± 1.1 | -1.9 | -0.7 | < .001 | 1.156 |
LAFH (mm) | 62.3 ± 6.5 | 63.4 ± 6.4 | 1.1 ± 0.8 | 0.7 | 1.6 | < .001 | 1.344 |
PFH (mm) | 67.5 ± 6 | 68.9 ± 5.9 | 1.4 ± 0.9 | 0.9 | 1.9 | < .001 | 1.510 |
U1-SN (°) | 100.6 ± 6.3 | 99.3 ± 6 | -1.4 ± 0.8 | -1.8 | -0.9 | < .001 | 1.630 |
U3 ANGLE (°) | 90.5 ± 5.6 | 85.1 ± 5 | -5.4 ± 3.7 | -7.3 | -3.4 | < .001 | 1.478 |
U6 ANGLE (°) | 69.7 ± 3.1 | 61.6 ± 3 | -8.1 ± 2.7 | -9.6 | -6.7 | < .001 | 3.030 |
L6 ANGLE (°) | 58.7 ± 5.2 | 53.5 ± 5.5 | -5.2 ± 3.4 | -7.1 | -3.3 | < .001 | 1.512 |
IMPA (°) | 97.6 ± 5.4 | 101.2 ± 5.4 | 3.5 ± 1.3 | 2.8 | 4.2 | < .001 | 2.632 |
IIA (°) | 125.3 ± 9.6 | 121.4 ± 10.4 | -3.9 ± 2.8 | -5.4 | -2.4 | < .001 | 1.370 |
U3 VP (mm) | 64.4 ± 4.7 | 67.4 ± 4.4 | 3 ± 2 | 2 | 4.1 | < .001 | 1.523 |
U6 VP (mm) | 60 ± 4.5 | 61.2 ± 4.7 | 1.2 ± 0.9 | 0.7 | 1.7 | < .001 | 1.341 |
L6m VP (mm) | 63.8 ± 4.7 | 62.3 ± 4.9 | -1.6 ± 0.8 | -2 | -1.2 | < .001 | 1.987 |
L6d VP (mm) | 61.5 ± 4.7 | 60.2 ± 4.9 | -1.3 ± 0.9 | -1.7 | -0.8 | < .001 | 1.361 |
L6 AP (mm) | 35.5 ± 4.6 | 37.2 ± 4.6 | 1.6 ± 1.2 | 1 | 2.3 | < .001 | 1.309 |
Model measurements | |||||||
MV- U3 | 37 ± 8 | 40.8 ± 8 | 3.8 ± 1 | 3.2 | 4.4 | < .001 | 3.635 |
MV- U6 | 30 ± 5.4 | 37.8 ± 7.3 | 7.7 ± 3.2 | 6 | 9.5 | < .001 | 2.397 |
MH- U3 | 10.7 ± 1.9 | 8.4 ± 2 | -2.3 ± 0.7 | -2.7 | -2 | < .001 | 3.497 |
MH- U6 | 13.9 ± 1.5 | 16.1 ± 1.5 | 2.2 ± 0.8 | 1.8 | 2.6 | < .001 | 2.804 |
ICW | 33.6 ± 3 | 35.9 ± 3.3 | 2..3 ± 0.7 | 1.9 | 2.7 | < .001 | 3.227 |
IMW | 45.4 ± 2.8 | 45.3 ± 3 | -0.1 ± 0.9 | -0.5 | 0.3 | .565 | 0.147 |
OJ | 4.7 ± 1.4 | 3.3 ± 1.2 | -1.4 ± 0.9 | -1.8 | -0.9 | < .001 | 1.622 |
OB | 3.7 ± 0.8 | 2.4 ± 1.1 | -1.3 ± 0.9 | -1.8 | -0.8 | < .001 | 1.393 |
Characteristic | IZCG | EXG | 95% CI | p-value | Cohen’s d | |
---|---|---|---|---|---|---|
Lower bound | Upper bound | |||||
SNA (°) | 0 ± 0.3 | -0.5 ± 0.7 | 0.1 | 0.9 | .019 | 0.879 |
SNB (°) | 0.2 ± 0.8 | 0.9 ± 0.5 | -1.1 | -0.2 | .008 | 1.004 |
ANB (°) | -0.1 ± 0.7 | -1.3 ± 1.1 | 0.5 | 1.9 | .001 | 1.240 |
LAFH (mm) | 0 ± 1.4 | 1.1 ± 0.8 | -1.9 | -0.3 | .012 | .946 |
PFH (mm) | 0.1 ± 1 | 1.4 ± 0.9 | -2 | -0.6 | .001 | 1.334 |
U1-SN (°) | -3.8 ± 2 | -1.4 ± 0.8 | -3.6 | -1.3 | < .001 | 1.618 |
U3 ANGLE (°) | -6.8 ± 4.9 | -5.4 ± 3.7 | -4.5 | 1.7 | .378 | 0.317 |
U6 ANGLE (°) | -5.8 ± 4.2 | -8.1 ± 2.7 | -0.2 | 4.9 | .073 | 0.657 |
L6 ANGLE (°) | 0.4 ± 0.8 | -5.2 ± 3.4 | 3.7 | 7.5 | < .001 | 2.236 |
IMPA (°) | -0.2 ± 0.7 | 3.5 ± 1.3 | -4.5 | -3 | < .001 | 3.512 |
IIA (°) | 3.4 ± 2.6 | -3.9 ± 2.8 | 5.4 | 9.3 | < .001 | 2.699 |
U3 VP (mm) | -0.5 ± 0.8 | 3 ± 2 | -4.6 | -2.4 | < .001 | 2.314 |
U6 VP (mm) | -1.7 ± 1.3 | 1.2 ± 0.9 | -3.7 | -2.1 | . < .001 | 2.671 |
L6m VP (mm) | 0 ± 0.5 | -1.6 ± 0.8 | 1.1 | 2.1 | < .001 | 2.443 |
L6d VP (mm) | 0 ± 0.5 | 1.3 ± 0.9 | 0.7 | 1.7 | < .001 | 1.682 |
L6 AP (mm) | -0.1 ± 0.2 | 1.6 ± 1.2 | -2.3 | -1 | < .001 | 1.846 |
Model measurements | ||||||
MV- U3 | 13.5 ± 5.9 | 3.8 ± 1 | 6.5 | 12.9 | < .001 | 2.286 |
MV- U6 | 15.6 ± 7 | 7.7 ± 3.2 | 3.9 | 11.9 | < .001 | 1.448 |
MH- U3 | -3.1 ± 0.9 | -2.3 ± 0.7 | -1.3 | -0.2 | .010 | 0.967 |
MH- U6 | 3.2 ± 1.2 | 2.2 ± 0.8 | 0.3 | 1.8 | .006 | 1.045 |
ICW | 10.7 ± 3 | 2..3 ± 0.7 | 6.8 | 10 | < .001 | 3.868 |
IMW | 0.9 ± 0.8 | -0.1 ± 0.9 | .04 | 1.6 | .001 | 1.251 |
OJ | -1.6 ± 1 | -1.4 ± 0.9 | -0.9 | 0.5 | .622 | 0.176 |
OB | 0 ± 0.8 | -1.3 ± 0.9 | 0.7 | 1.9 | < .001 | 1.508 |