Objective: This study was designed to evaluate the effect of corticotomy and miniplates' usage as skeletal anchorage for maxillary molars' intrusion during correction of skeletal anterior open bite (SAOB). Patients, materials and methods: A sample of 22 patients with an age range from 14 to 22 years, suffering from skeletal anterior open bite with increased posterior maxillary vertical height. The participants were randomly divided into two groups according to the corticotomy approach. Group I: both buccal and palatal corticotomies were performed. Group II: only buccal corticotomy was performed. Buccal miniplates and palatal mini-screws were used as skeletal anchorage for maxillary molars' intrusion assisted by corticotomy. The measurements, including maxillary dento-alveolar heights (mm), bucal crestal alveolar bone heights (mm), bucco-palatal angulations (B-P˚) and mesio-distal angulations (M-D˚) of right and left maxillary first permanent molars, 4.5 months after intrusion commencement. Results: The dento-alveolar height as well as the buccal crestal alveolar height decreased significantly after intrusion in both groups (p≤0.001 and p≤0.05, respectively), but without significant differences between them. Similarly, the M-D and B-P angulations increased significantly after intrusion in both groups (p≤0.01 and p≤0.001, respectively), with no significant differences between both groups. Conclusions: The current corticotomy approaches and temporary anchorage devices (TADs) were similarly effective for maxillary molar intrusion in cases of (SAOB), but complete correction of SAOB was not achieved. Both the posterior maxillary dento-alveolar and buccal crestal alveolar bone heights diminished similarly in both corticotomy methods. Neither mesio-distal nor bucco-palatal angulations of maxillary first permanent molar crown revealed major changes in matching both approaches of intrusion.

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.