Maxillary deficiency or retrusion is generally accepted as one of the most difficult and complex orthodontic anomalies to diagnose and treat. Facemask therapy is usually preferred for the treatment of subjects with skeletal and dental Class III malocclusions with a retruded maxilla, and it is known that if the patient is sufficiently motivated to wear a facemask, this type of therapy is quite successful. patient compliance required during facemask therapy due to its poor aesthetics and intraoral appliances for Class III malocclusion treatment such as the Fränkel III , bionator III don't give treatment goals .Hybrid appliance tandem traction bow appliance (TTBA)is introduced by Chun et al. 1999 , as a more aesthetic, effective and comfortable device. Klempner, 2003 modified tandem appliance and published two case reports suggested that TTBA and modified applications have a similar treatment effect to that of an expander-facemask combination(2). A review of the literature showed that there were no statistical studies documenting the effects of modified tandem appliance comparing to traditional expander-facemask therapy and these are the investigators study purposes.