Objective: Investigating the reliability of mandibular canine maturation stages in predicting pubertal growth spurt in a sample of Egyptian orthodontic patients. Subjects and Methods: A retrospective, cross-sectional study was carried out on the radiographic records (left lateral cephalometric, panoramic, and left hand and wrist x-rays) obtained from 250 patients who were attending private clinics on Delta area, Egypt. The age of the patients ranged from 7 to 18 years. Mandibular canine calcification stages (MCC) were assessed according to Demirjian's method for dental maturity assessment. Skeletal maturity was assessed by the ossification stages of the middle phalanx of the third finger (MP3) using Hagg and Taranger method, and the cervical vertebrae maturation index (CVMI) was evaluated using Hassel and Farman method. Results: Chi-square tests have shown highly significant associations between the mandibular canine calcification stages (MCC) and both CVMI and MP3 maturation stages (p<0.001). MCC stage F had shown a moderate correlation with MP3 FG and CVMI 2 that corresponded to the onset of pubertal growth. Conclusions: MCC stage F can be used for prediction of the onset of pubertal growth, while the prediction of the peak or the post-peak periods using MCC method may be unreliable.

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Objective: To evaluate the pharyngeal airway volume following treatment of skeletal Class II mandibular retrusion with miniplate-anchored Herbst appliance by Cone Beam Computed Tomography (CBCT). Materials and Methods:Fourteen female Class II post-pubertal patients with mandibular retrusion were randomly selected with mean age was 16.7±1.56 years. As a first orthodontic phase, they were treated by type IV Herbst functional appliance that anchored by two reconstructive plates located bilaterally in the mandible between the canine and first premolar teeth, while attached to the maxilla through dental splints utilizing orthodontic bands. The CBCTscans were obtained before treatment (T1) and immediately after removal of Herbst appliance (T2) for volumetric pharyngeal airway evaluation. In addition, sagittal cephalometric parameters were analyzed.Results:Paired sample t-testshowed a non-statistically significant (p>0.05) increase (585 mm3) in nasopharyngeal airway volume with treatment, whereas velopharyngeal airway, glossopharyngeal airway and total airway volume showed statistically significant (p<0.01) increases after Herbst appliance treatment by 2448mm 3 , 1107mm 3 , 2607mm 3 , respectively. Moreover, an improvement in mandibular retrognathism was evident as demonstrated by significant increase in SNB angle and significant decrease in ANB angle (p<0.05).Conclusions: Pharyngeal airway volume considerably enhanced subsequent to mandibular advancement through miniplateanchored Herbst appliance which could be a helpful treatment opportunity for post-pubertal patients who have skeletal Class II malocclusion with mandibular retusion and suffering breathing disorders.