Evaluation of two types of treatment for adolescent patients with protrusion of lower jaw and constriction of upper jaw

For the BAIMT with RME group: The duration of the procedure will be about 12 months included Sagittal and transverse correction stage and retention stage . This procedure will be carried out initially by the orthodontist and later by The patient or one of his parents The patient or one of his parents will activate the expander twice daily (0.4 mm) until an overcorrection of maxillary constriction about 2-3 mm will be obtained (experimental group): bone-anchored intermaxillary traction (BAIMT) associated with rapid maxillary expansion(RME) group Orthodontic procedures: 1. Active phase period: The group: BAIMT with RME The appliance consists of (1) bonded modified Hyrax palatal expander with occlusal splints bonded with GIC on the upper premolars/deciduous molars and upper first molars, (2) hooks (made of 0.9 mm stainless steel wire) for attaching elastic bands placed distal to the first molars . Two self-drilling mini-implants (1.6 mm diameter, 8 mm length) will be inserted under local anesthesia into the buccal alveolar bone between the mandibular canine and the first premolar roots on both sides with an insertion angle of about 45° to 60° with the alveolar process. A periapical radiograph will be taken beforehand to assure proper insertion without damaging the neighboring roots . Intermaxillary elastics will be applied between the hooks and the mandibular anterior mini-implants, generating a 100 g force on each side of the jaw; in the first week (5/16 inch) followed by 3/16 medium size to generate an orthodontic force of about 200 g on each side until the end of treatment. Patients will be asked to wear elastics for 16 hours per day and replace elastics daily or when they will get damaged . The patient or one of his parents will activate the expander twice daily (0.4 mm) until an overcorrection of maxillary constriction about 2-3 mm will be obtained . The patients in the two groups will be seen within one week, following the appliance’s first insertion, two weeks following the first insertion, and then at monthly visits to observe the change in incisor relationship, monitor patient’s compliance by the researcher himself . Change in the incisor relationship from a negative overjet (i.e., + 1.5 mm or greater) will be considered the sign of successful treatment in the sagittal plane. If the defect in the transverse plane will be corrected before the one in the sagittal plane, the expansion will be stopped while the patient will be asked to continue wearing the appliance until the defect in the sagittal plane will be corrected and vice versa. The questionnaire will be distributed to the patients at five times by the researcher himself: (T1) after one day of the beginning of the treatment, (T2) after one week (T3) after four weeks, (T4) after three months, (T5) after six months. The questionnaire will be filled in by the patient at the five times.