Through clinical analysis and evaluation of the outcomes of using- straight wire appliance at Angles to treat class I malocclusion for 127 patients by Cohort study method and concluded that: - In Class I malocclusion, class I of Dewey Anderson's modification occured most often: 50,40 percent of all types. - Clinical results of treated class I malocclusion patients were: - 74,8 percent of the patients showed normal appearance of the front of their faces. - Periodontal tissues and