الفهرس 
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Abstract
The introduction of bone-anchored maxillary protraction (BAMP) with Class III intermaxillary elastics and miniplates eliminated the side effects of the conventional facemask in the early treatment of retrognathic maxilla. This randomized controlled trial aimed to evaluate the effects of Class III elastics stretched between the maxillary hybrid hyrax (HH) to a bone-anchored mandibular bar compared with growth changes in an untreated control group, in growing maxillary retrusive patients. Methods : Forty growing Class III patients with the retrognathic maxilla, were recruited with a random and equal allocation into 2 groups; treated and control. In the treated group, 2 paramedian orthodontic miniscrew implants (OMIs) were inserted in the anterior palate and 2 interradicular OMIs were inserted into the anterior mandible between the canines and lateral incisors. The palatal OMIs were connected to a hyrax expansion screw forming the HH appliance. The mandibular OMIs were connected by a bar with hooks for elastic attachment. Alternate maxillary expansion and constriction (Alt-RAMEC) protocol was applied for 9 weeks before starting maxillary protraction. After that, intermaxillary Class III elastics were worn 24 hours per day and stretched between the HH and the hooks of the mandibular bar applying 200 g of force. Protraction was stopped after obtaining positive overjet. Cephalometric radiographs were acquired at the beginning (T1) and end of treatment (T2). The paired-samples and independent-samples t-tests were used to evaluate and compare the changes within groups and between groups, respectively. Results : Forty patients agreed to participate and 30 of them finished the study (treated: 17, control: 13). The average treatment duration was 11.9 months. In the treated group, there was a significant maxillary advancement (4.34 mm) with significant control on the mandibular growth. No significant increase in the mandibular plane angle was found in the treated compared with the control group. In the treated group, the upper and lower incisors showed a significant proclination. The upper molars showed significant extrusion and mesialization. Significant profile improvement reflected the underlying skeletal changes. Conclusions : The proposed treatment protocol for maxillary protraction can effectively increase the maxillary forward growth with better control on the forward growth of the mandible and the vertical changes. ”