Geometrically Investigating the Effect of Maxillary Posterior Impaction on Mandible Autorotation in Patients with Anterior Openbite Using Proplan CMF Software on Available CT Scans

Background: Posterior impaction of the maxilla leads to spontaneous rotation of the mandible and these rotations are often accompanied by soft tissue and skeletal changes. The present research aims to determine the effects of posterior impaction of the maxilla on mandible's Autorotation in patients with anterior open bite. Methods and material: Using a 3D reconstructed model of 25 patients with anterior open bites, this descriptive study is conducted. The construction model of the posterior segment of the mandible design was subjected to 2, 3, 5, and 7 mm posterior impaction of the maxilla around the ANS axis without any mandibular intervention, using the available CT scan and ProPlan CMF software. Following this, the autorotation and anterior open bite correction were assessed. A basic linear regression test was used to examine the effects of various variables on the anterior open bite closure at various impaction rates. Results: The rise, in impact rate led to an increase in the byte closure rate. With 2, 3, 5 and 7 mm posterior impaction of the maxilla, the bite closure was not significantly affected by maxilla length, mandible length, U1-SN angle, ANS-PNS angle with the maxillary occlusal plane, or mandibular incisor angle with the mandibular plane. Nevertheless, during the 5 mm posterior maxillary impaction procedure, there was a 0.25 mm increase in the open bite closure for every 1 degree increase in IMPA; this number is statistically significant. (p<0.001). Conclusion: The amount of bite closure increased along with the posterior impaction of the maxilla. All other variables did not significantly affect bite closure rate, with the exception of the IMPA variable in 5 mm impactions.