Objective: To evaluates the dental-alveolar bone changes at the initial stage of non-extraction treatment of classIIdivision 1 case.
Methods: Seven patients with Angle classIIdivision 1 malocclusion of early permanent dentition(11.3 to 13.4 years old) were included in this study. They were non-extraction treated with use of Alexander brackets and cervical headgear. Initial treatment started from upper arch, after aligning upper arch, it was consolidated and a cervical headgear was worn for 3.54 months averagely. During this stage, lower arch had already not started. Lateral cephalogram and study model (upper) were taken at beginning of the treatment(T1) and in the middle of the treatment after using face-bow for 3.54 monthsaveragely(T2). Model parameters and lateral cephalogram parameters were examined at T1 and T2. Data were correlated by means of paired t-tests.
Results: The width of the upper arch was increased significantly, the inclination of the upper incisor anterior-posteriorly and the overjet were decreased significantly. Above results showed statistical significance.
Conclusion: According to this study, the continuous arch wire of the fixed appliance combined with the cervical headgear can decrease the inclination of the upper incisor anterior-posteriorly and overjet due to the expansion of the width of the upper arch at initial stage of treatment, the mandible can express its potential growth sagittally while unlocking the original occlusion by treatment in the upper arch. This effective way can reduce the use of class II elastics and tipping labially of the lower incisor for decreasing overjet at later treatment.