Evaluation of molar distalization in patients with class ii division 1 malocclusion treated with infra-zygomatic crest screws

This thesis study was conducted to evaluate the amount of molar distalization which occurred in patients with buccal segment distalization with the "Infra Zygomatic Crest Screw". Participants of this study were chosen from among patients who have relation as Class I or Class II based on their skeletal and Class II molar and canine based on their teeth. In addition, the following criteria were taken into consideration in patient recruitment: (a) no absence of tooth in the maxillary arc, (b) minimal crossing in the mandibular arch, (c) contraindication of functional treatment (d) increased overjet, (e) maxillary second molars completely erupted. 19 patients meet with all these criteria were chosen for this study. The lateral cephalometric radiographs pre and post distalization belong to all patients were used in this study. At the beginning of distalization, leveling phases of 19 patients with an average age (15.82 ± 1.85) were completed and distalization force was applied on this arc after the 0.017x0.025 stainless steel back. One month after applying the mini screws to the zygoma region, the chain was applied to press 300g force between the screw head and the hook of the canine bracket. The elastic chain was renewed every four week. The force was renewed every four weeks until the desired amount of distalization was achieved. Distalization was ended when a class I molar and canine relationship was obtained. At the end of distalization, a total of 25 parameters were measured on 38 lateral cephalometric films taken pre and post distalization. Distalization lasted 7,03 month. An average of (3,156 ± 0,89) mm distalization was obtained in molar teeth. While the maxillary incisors retracted on average (3,97 ± 1,84) mm, there was (3,747 ± 1,99) mm reduction in the overjet. Key Words: Infra Zygomatic Crest Screw, Molar Distalization, Buccal Segment Distalization