Thesis (Ph.D.) - Cairo University - Faculty of Oral and Dental Medicine - Department of Orthodontics

Objective: The current study was a Randomized Controlled Trial (RCT) that was performed to investigate three-dimensionally the effect of posterior cross bite correction using Quad-helix appliance on the TMJ as compared with untreated matched control subjects. Material and Methods: Sample size calculation was carried out and resulted in enrollment of 26 subjects in the study. The selected subjects had the criteria of unilateral posterior cross bite that require maxillary expansion as a part of their individual treatment plan. The age of subjects ranged between 9 to 13 years with skeletal maturation stage range between CS1 and CS3. The subjects were randomly allocated to two groups; Group1 who received maxillary expansion and Group 2 who considered as control with no treatment for 6 months. Results: Anteroposterior condylar asymmetry was decreased after correction of posterior cross bite by posterior displacement of the non crossbite condyle and anterior displacement of the cross-bite condyles. A more centralized position of the condyles in the joint cavities was achieved after expansion as evident by increased AJS and decreased PJS in the non crossbite side with concomitant decreased AJS and increased PJS in the cross bite side

Issued also as CD