Table 4 Characteristics of included studies
Authors of the study | Ugolini et al. [24] | Nieri et al. [35] |
|---|---|---|
Study design | RCT | RCT |
Sample size | 101 subjects  48 in RME group  53 in SME group | 56 subjects  28 in RME group  28 in SME group |
Mean age of the subjects | RME: 9.4 years (range 6–13 years) SME: 9.1 years (range 6–13 years) | RME: 8.4 ± 1.0 years SME: 8.0 ± 1.3 years |
Sex of the subjects | RME: 26 F; 23Â M SME: 28 F; 25Â M | RME: 12 F; 16Â M SME: 17 F; 11Â M |
Cervical stage | CS 1—CS 3 | RME: 21 subjects in CS 1; 6 subjects in CS 2 SME: 24 subjects in CS 1; 4 subjects in CS 2 |
Inclusion criteria | Transversal maxillary deficiency (intermolar width < 30 mm, with or without crossbite) Class I or Class II dental malocclusion Cervical vertebral maturation stage 1–3 | A posterior transverse interarch discrepancy of at least 3 mm Early or intermediate mixed dentition stage with fully erupted upper and lower first permanent molars Prepubertal (cervical stage 1 or 2) |
Exclusion criteria | Previous orthodontic treatment Hypodontia in any quadrant excluding third molars Inadequate oral hygiene craniofacial syndromes, cleft lip or palate | Pubertal or post-pubertal stage of development (CS 3–6) Late deciduous or mixed dentition Agenesis of upper second premolars (assessed on initial panoramic radiograph) Cleft lip and/or palate and craniofacial syndromes Patients unable to be followed for at least 1 year |
Type of appliance used for expansion | RME: Hyrax expander SME: Leaf expander | RME: Butterfly expander SME: Leaf expander |
Anchorage teeth | Second primary molars | Second primary molars |
Activation protocol | RME: two activations at the application of the expander and then two quarter-turns a day, one in the morning and one in the evening (0.40Â mm/d) SME: pre-activation in the laboratory to deliver the first 3Â mm expansion, and then, reactivation performed in the office by 10 quarter-turns of the screw per month | RME: a quarter of a turn per day SME: pre-activation of the screw causing the first 3Â mm of expansion, then reactivation was performed in the office by 10 quarter-turns of the screw per month |
Type of PROMs evaluated | Pain (1–7 days of screw activation)—presence, intensity, location, for how many days Jaw function impairment  Speaking  Salivation (hypersalivation)  Swallowing | Pain (in the first 12 weeks)—primary outcome—presence, intensity Difficulty in speaking Expander Hygiene Patients’ and parents’ satisfaction |
Type of questionnaire used for PROMs assessment | A questionnaire (modified from Feldmann and Bazagani, 2017 [31]) A Wong–Baker Faces Pain Scale with a complementary numeric rating scale from 0 to 10 | A questionnaire including all PROMs evaluation VAS and Wong–Baker Faces Pain Scale for pain assessment with a complementary numeric rating scale from 0 to 10 |
Duration of treatment | Until overcorrection | When the palatal cusps of the upper second deciduous molars approximated the buccal cusps of the lower second deciduous molars |
Follow-up | RME: 9Â months SME: 9Â months | Both expander types were removed 1Â year after the start of therapy |