December 2007

Document Type


Degree Name



Dept. of Orthodontics


Oregon Health & Science University


The purpose of this retrospective chart review study was to compare the differences that occurred when high mandibular plane angle (MP-SN > 36°) Class II patients were treated with cervical headgear vs. those treated with high-pull headgear. The high-pull sample was gathered from the orthodontic records of Dr. Bruce Fiske, and the cervical headgear subjects from the practice of Dr. David Cruikshank. The treated groups consisted of 28 high-pull headgear subjects (21 females, 7 males) and 34 cervical headgear subjects (18 females, 16 males). Along with headgear, patients were treated with full orthodontic straight wire appliances (.022x.028in.) and Class II elastics as needed. Several patients in the high-pull sample also had a quadhelix palatal expander placed for a short time at the beginning of treatment. No control group was employed since the focus of this study was to determine what happened when experienced clinicians treated patients using techniques of their own choosing. Pretreatment (T1) and posttreatment (T2) lateral cephalometric radiographs were obtained for each of the subjects. The cephalograms were scanned and digitized using QuickCeph Studio 2007 cephalometric software. Cephalometric measurements were recorded and intergroup differences were analyzed by the use of the independent t-test. Sagittal changes as a result of treatment were not found to be significantly different between the two groups. Vertically the Y axis increased significantly more in the cervical group (1.6°) than in the high-pull group (0.4 °). The occlusal plane angle increased in the cervical group (1.2 °) and slightly decreased in the high-pull group (0.5°). The changes observed in the mandibular plane angle were not statistically different between groups. The linear dimensions measured showed a statistically significant difference in the lower facial height where the cervical headgear group exhibited an increase of5.6 mm and the high-pull headgear group showed a 3.9 mm increase. Although some of the angular and linear changes produced by the two different protocols were significantly different, the clinical significance was questionable since the changes exhibited by the different headgear systems were small. Based on the results of this study either type of headgear system seemed to be acceptable for treatment of high mandibular plane angle cases.




School of Dentistry



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