Aim: To evaluate the treatment results of the orthodontic treatment of adult open bite cases. To assess the accuracy of the Hp angle for measuring mandibular rotation.
Materials and Methods: 38 Adult Patients of the Maimonides University, Buenos Aires, Argentina with open bite were evaluated in reference to their mandibular rotation. Three groups were evaluated: 1-patients undergoing their first orthodontic treatment; 2- patients who had undergone a surgical treatment and relapsed; 3- patients in their first orthodontic treatment. The mandibular rotation was measured on lateral X-Rays. The mandibular rotation was assessed using the HP angle. The angle was measured at T1: pre-treatment and T2: after teatment.
Results: In all groups there were significant changes in the mandibular rotation. This could be due to the biomechanics as to the habits correction. The mandibular rotation could be seen as a compensation mechanism, compared to a skeletal change. The angle appeared to be a simple and accurate tool for meassuring mandibular rotation.
Conclusion: The open bite correction in adult patients occur mostly due to mandibular rotation, as showed by the changes in the HP angle. This angle showed to be a useful and accurate aid in the diagnosis of mandibular rotation and position.