INTRODUCING A NEW REMOVABLE APPLIANCE FOR INTRUSION OF POSTERIOR TEETH
Abstract
Introduction. In patients with anterior open bite, wether with skeletal factors, or with dental factors, the excessive eruption of posterior teeth, is one of the specific findings, and this excessive eruption causes the backward and downward rotation of mandible, which results in an increase in lower facial height and steep mandibular plane. In these patients, depressing of posterior teeth is the ideal treatment and to achieve this goal is one of the most difficult tooth movements for orthodontist.
Methods. For this purpose, a removable appliance was designed and to evaluate its eficacy, six patients were selected, four of them were in permanent dentition and two in mixed dentition period. They were under treatment with this appliance, full time for three to three and a half months. Before starting treatment, lateral cephalometric radiograph and study casts were prepared and the above mentioned period were repeated. The amount of bite closure was measured by comparing study casts before and after treatment. Also cephalometric changes were evaluated by comparing pre-and-post treatment records.
Results. As a result average of maxillary first molar intrusion was 1.1 mm and average of mandibular first molar intrusion was 1.3 mm , which had resulted in upward and forward rotation of the mandible. The average changes due to mandibular rotation were: The amount of bite closure 3.7mm; Decrease in lower facial height 3mm; Prominence of chin 3.2 mm; Decrease in mandibular plane angle 2.3; Decrease in y-axis angle 2; Increase in facial angle 2.3.
Discussion. Therefore it is obvious that clinically the suggested appliance is capable of, intruding posterior teeth in both of maxilla and mandible and then due to upward and forward rotation of the mandible, the steep mandibular plane and lower facial height are decreased. Now according to the results of this investigation can be highly hopefull that, the number of patients who need orthographic surgery, for correction of anterior open bite to be diminished.
Methods. For this purpose, a removable appliance was designed and to evaluate its eficacy, six patients were selected, four of them were in permanent dentition and two in mixed dentition period. They were under treatment with this appliance, full time for three to three and a half months. Before starting treatment, lateral cephalometric radiograph and study casts were prepared and the above mentioned period were repeated. The amount of bite closure was measured by comparing study casts before and after treatment. Also cephalometric changes were evaluated by comparing pre-and-post treatment records.
Results. As a result average of maxillary first molar intrusion was 1.1 mm and average of mandibular first molar intrusion was 1.3 mm , which had resulted in upward and forward rotation of the mandible. The average changes due to mandibular rotation were: The amount of bite closure 3.7mm; Decrease in lower facial height 3mm; Prominence of chin 3.2 mm; Decrease in mandibular plane angle 2.3; Decrease in y-axis angle 2; Increase in facial angle 2.3.
Discussion. Therefore it is obvious that clinically the suggested appliance is capable of, intruding posterior teeth in both of maxilla and mandible and then due to upward and forward rotation of the mandible, the steep mandibular plane and lower facial height are decreased. Now according to the results of this investigation can be highly hopefull that, the number of patients who need orthographic surgery, for correction of anterior open bite to be diminished.
Keywords
Open bite, Intrusion