Table 6: Results of the intergroup comparison of the maxillary and mandibular dental arches dimensions between the initial and final stages (T2-T1) (independent t or Mann-Whitney tests).

Variables (mm) Group 1
Damon
(N=21) 		Group 2
Conventional
(N=24) 		P
Mean (Median) S.D. (i.r.) Mean
(Median) 		S.D. (i.r.)
Mx IC 1.22 (1.36) 0.95 (0.87) 0.08 (-0.27) 1.66 (1.69) 0.000*¥
Mx I1PM 2.44 1.12 1.06 1.56 0.001*€
Mx I2PM 2.27 1.16 0.93 1.63 0.003*€
Mx IM 1.87 1.38 0.71 1.50 0.010*€
Mx AL 0.99 1.80 1.02 2.33 0.958 €
Md IC 1.16 1.29 -0.19 1.08 0.000*€
Md I1PM 1.88 1.89 0.66 1.50 0.020*€
Md I2PM 1.65 1.51 0.65 2.30 0.100 €
Md IM 0.97 1.31 0.50 1.35 0.243 €
Md AL 0.69 (0.54) 2.33 (1.13) 1.83 (1.92) 1.95 (1.52) 0.024*¥

Mx=maxillary; Md=mandibular; IC=intercanine distance; I1PM=inter first premolar distance; I2PM=inter second premolar distance; IM=intermolar distance; AL=arch length.
Mean and Standard Deviation (S.D.) when using independent parametric t test; median and interquartile range (i.r.), when using the non-parametric Mann-Whitney test.
* statistically significant for p <0.05
€ independent test
¥ non-parametric Mann-Whitney test