Cephalometric evaluation of anterior open-bite nonextraction treatment, using multiloop edgewise archwire therapy.

There are very few reports of extensive and detailed cephalometric investigations of nonextraction treatment changes for patients with anterior open bite. The purpose of this study was to evaluate changes in dentomaxillofacial morphology by way of lateral and oblique cephalograms of patients who had undergone multiloop edgewise archwire (MEAW) therapy for anterior open-bite correction. The subjects consisted of 21 Japanese female patients who received MEAW therapy without premolar extraction. The mean pre- and posttreatment ages were 16 years 9 months and 19 years, respectively. Lateral and oblique cephalograms were taken before and after treatment. Fifteen angular and 29 linear measurements were obtained from the lateral cephalograms; 17 angular and 20 linear measurements were obtained from the oblique cephalograms. Treatment changes were evaluated by the paired t-test. The upward and forward rotational changes of the mandible consequent to the use of the MEAWs and anterior vertical elastics were larger than the downward and backward rotational changes of the mandible, due to the extrusion of the posterior teeth by leveling and alignment. The uprighting and retrusion of the premolars and molars, and the extrusion, uprighting, and/or retrusion of the incisors and canines played important roles in the anterior open-bite nonextraction treatment by dint of the MEAW technique.