Table 1.

Patients: Number (n), age, gender, average wear time of the RME, average number of Hyrax screw activations, percentage of maximum possible turns of the Hyrax screw (%), localisation of the crossbite and mandibular deviation for the total patient group and the patient groups PG 1 (early) and PG 2 (late). M Mean and SD standard deviation

Patients	Patients pooled	Patient group 1 (PG 1)	Patient group 2 (PG 2)
Number (n)	114	57	57
Age (years)	11.03 ± 2.59	9.13 ± 1.33	12.93 ± 2.09
Gender (m/f)	47 m/67 f	21 m/36 f	26 m/31 f
RME wear time (months)	6.15 ± 1.98	6.20 ± 2.24	6.11 ± 1.70
Number of Hyrax screw activations	24.33 ± 6.56	24.33 ± 6.41	24.33 ± 6.71
Maximum possible turns of the Hyrax screw (%)	48.67 ± 13.12	48.67 ± 12.93	48.67 ± 13.41
Crossbite (n) bilateral/only right/only left	61/33/20	26/17/14	35/16/6
Mandibular deviation (n) none/right/left	63/34/17	25/20/12	38/14/5