Introduction
TB, malocclusion, palate, dentofacial anomalies, Class II malocclusion, malocclusions
Skeletal Class II malocclusion is considered one of the most common dentofacial anomalies affecting almost one-third of the population [As a result of mandibular retrognathism, the space between the cervical column and the mandibular corpus is diminished, the tongue and soft palate are posteriorly postured; consequently, narrowing the airway dimensions [The Twin Block (TB) is one of the preferred removable functional appliances used in correcting retrognathic mandible in developing Class II malocclusion patients [Soft, non-customized PFAs are often utilized in combination with myofunctional training, setting them apart from traditional functional appliances. In contrast to other kinds of full-time functional appliances (e.g., Twin Block, Herbst), they are only worn part-time (like the conventional ‘activator’). Clinical research comparing the effects of PFAs to conventional functional appliances has just been published recently, despite the fact that PFAs have been used for decades [The Myobrace (MB) is a ready-made orthodontic appliance employed for correcting malocclusions in children and teenagers with late mixed dentition [Lateral cephalometry, with its routine use, cheap cost, minimum exposure to radiation, and enough information provided regarding the pharyngeal airway compared to those obtained from three-dimensional cone-beam computed tomography (CBCT), is the recommended approach in this study [Although the efficiency of the functional appliances to increase the airway dimensions has been widely investigated in the literature, none of the previous studies have compared the effect of TBA and Trainer for kids (MB) on the pharyngeal airway during the pubertal growth period, throughout a prospective clinical trial. Thus, our goal with this research was to evaluate the relative effectiveness of the Twin-block versus MB appliances in improving the sagittal pharyngeal airway dimension (SPAD) in adolescents having skeletal Class II malocclusion with retrognathic mandible, through a randomized clinical trial. Moreover, sagittal and vertical skeletal changes accompanying each of the tested appliances were assessed. The null hypothesis of this study there is no difference between the studied appliances regarding their effect on the SPAD.