The Relationship Of Skeletal Class â…¢ Patients Between Dental Decompensation And Lower Incisors Lip Moving

ObjectiveTo investigate the changes of measurement index such as L1-MP and L1-Y by analysizing the cephalometric index of the skeletal ClassⅢpatients' pre- and post- dental decompensation. The aim of this areticle is to provide the references for the clinical plan of orthodontic treatment and dental decompensation.MethodsThe sample consisted of 26 patients with skeletal classⅢmalocclusion treated by orthodontics and orthognathic surgery in China Medical University. Lateral cephalograms taken pre-and post-dental decompensation were analyzed. Take N as a standard point, anterior cranial base plane clockwise circle 7°as X-axis, make a vertical line cross N as Y-axis. The changes of MP-SN, OP-SN, L1-MP, L1-Y, B-Y, Pog-Y pre- and post- dental decompensation were compared and the ratios of the changes between L1-MP and L1-Y were calculated.ResultsAfter the preoperative orthodontic treatment, the changes of MP-SN, OP-SN, B-Y, Pog-Y were not statistically significant (P＞0.05). The increases in L1-MP and L1-Y were statistically significant (P＜0.01).The average of L1-MP into a 74.1°by 87.0°, while the average of L1-Y into a 67.9 mm by 71.9 mm. The ratio of L1-MP to L1-Y was 12.9°/4.0mm (≈3.2°/mm).Conclusion1. The preoperative orthodontic treatment can greatly improve the relationship between lower incisors and mandibular. 2.The preoperative orthodontic treatment in skeletal ClassⅢpatients had no evident influence on alveolar bone, MP-SN and OP-SN.3.L1-MP was changed, so was L1-Y after dental decompensation. A relationship exists between the data.