The Effect Of Different Force Levels for Maxillary Protraction on The Upper Inciosrs’ Position in Growing Class 3 Patients

Objective: To evaluate changes in the anterior maxillary dentoalveolar segment concomitant with different levels of force application for maxillary protraction in growing skeletal class3 patients. Subjects and Methods: The current study was conducted on 30 class 3 patients (19 boys and 11 girls) with maxillary difficieny. The age of the recrutted sample ranged from 7-10 years. The patients were randomely allocated into three equal groups. The point of protraction force application varied among the three groups; group A at the occlusal plane, group B 20 mm above the occlusal plane and group C at the infraorbital foramen. The duration of the treatment laste for 8 months, the patients were instructed to werethe appliance 16 hour/day with the applied 550gs protraction force. The analysis of the outcomes of this study was doneusing CBCT images were taken before and after maxillary protraction. Results: The average amount the upper midface projection varied significantly (p˂ 0.05) among the three studied groups as demonstrated by L&R IOF –TVP. The maximum amount of the upper midface anterior displacement was observed in group C (2.65 mm) followed by group B (1.77 mm) . the least amount of displacement was observed in group A (0.93 mm) . Conclusions: The application of the protraction force in a level higher than the occlusal plane is an efficient tool to maximized the amount of upper midface projection after protraction facemask without affecting the amount of maxillary advancement.