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Table 2 Comparison of the changes during treatment (T2–T0) between the two groups

From: Mini Hyrax vs Hyrax expanders in the rapid palatal expansion in adolescents with posterior crossbite: a randomized controlled clinical trial

Measurements Differences between groups T0
Mean (SD)a
Mini Hyrax-group T2–T0
Mean (SD)
Hyrax-group T2–T0
Mean (SD)
Difference between groups
Mean (SD)
p valuea Effect size CI (95%) Coefficient (95% CI)/p valueb
Distance 14–24 (mm) 0.50 (3.55)c 6.55 (0.72) 6.51 (1.19) 0.04 (0.90) 0.914 0.04 − 0.66–0.74 − 0.17 (− 0.87–0.52)/0.608
Distance 15–25 (mm) − 1.14 (7.19)c 6.38 (0.64) 6.09 (1.01) 0.29 (0,86) 0.347 0.34 − 0.36–1.04 − 0.33 (− 0.94–0.28)/0.276
Distance 16–26 (mm) 0.35 (5.51)c 6.23 (0.68) 5.93 (0.75) 0.30 (0.72) 0.272 0.41 − 0.29–1.11 − 0.27 (− 0.78–0.24)/0.290
Rotation 14 (o) − 3.09 (12.92)c 0.76 (5.48) 0.27 (5.30) 0.49 (5.34) 0.803 0.09 − 0.61–0.79 − 1.06 (− 5.08–2.94)/0.588
Rotation 24 (o) − 1.18 (11.09)c 0.62 (5,98) − 0.84 (6.11) 1.46 (5.92) 0.512 0.24 − 0.46–0.94 − 1.14 (− 5.90–3.60)/0.623
Rotation 15 (o) − 6.31 (13.23)c 1.05 (6.06) 1.77 (3.03) − 0.72 (4.12) 0.682 0.15 − 0.55–0.85 0.83 (− 3.09–4.76)/0.666
Rotation 25 (o) − 1.85 (13.36)c − 1.05 (5.77) 0.48 (3.31) − 1.53 (4.22) 0.380 0.32 − 0.38–1.02 2.05 (− 1.08–5.19)/0.190
Rotation 16 (o) − 3.29 (10.02)c 0.07 (2.57) − 1.10 (3.94) 1.17 (3.36) 0.341 0.35 − 0.35–1.05 − 1.06 (− 3.78–1.65)/0.427
Rotation 26 (o) − 4.29 (10.09)c 0.67 (3.55) − 0.68 (3.83) 1.35 (3.61) 0.322 0.36 − 0.34–1.06 − 2.26 (− 4.68–0.16)/0.067
Inclination 14 (o) 0.39 (7.49)c 10.81 (5.84) 11.27 (5.25) -0.46 (5.12) 0.822 0.08 − 0.62–0.78 0.14 (− 4.01–4.30)/0.943
Inclination 24 (o) 0.59 (8.16)c 11.78 (5.09) 9.25 (6.31) 2.53 (5.89) 0.238 0.43 − 0.27–1.13 − 2.76 (− 7.07–1.54)/0.199
Inclination 15 (o) 0.34 (7.29)c 10.16 (4.19) 10.43 (3.41) -0.27 (3.29) 0.848 0.07 − 0.63–0.77 0.02 (− 2.92–2.96)/0.989
Inclination 25 (o) − 0.18 (12.66)c 12.17 (3.35) 9.47 (3.75) 2.70 (3.46) 0.047 0.71 0.01–1.41 − 2.68 (− 5.42to − 0.04)/0.049
Inclination 16 (o) − 2.09 (10.41)c 1.75 (4.45) 1.53 (3.03) 0.22 (3.98) 0.876 0.05 − 0.65–0.75 − 0.52 (− 3.47–2.41)/0.715
Inclination 26 (o) 0.60 (13.90)c 2.79 (3.51) 1.79 (2.90) 1.00 (3.26) 0.404 0.31 − 0.39–1.01 − 0.84 (− 3.33–1.63)/0.489
  1. aStudent t test (independent samples). Level of significance p < 0.05. SD standard deviation, CI confidence intervals, disp displacement, mm milimeters, o degrees. Rotation measurements: means with negative sign indicates counterclockwise rotation, Inclination measurements: mean with negative sign indicates lingual inclination of teeth on the right side and buccal inclination of teeth on the left side
  2. bRegression analysis assessing differences between Mini-Hyrax and Hyrax groups of the dental changes (T2–T0), controlling for the dental measures at T0, participants’ age and number of activations of the appliance. Level of significance p < 0.05
  3. cDenotes no difference between groups. p > 0.05