The Clinical Research Of Orthopedic Treatment In ClassⅡ Malocclusion With Or Without Temporomandibular Joint Internal Derangement

Objectives This cephalometric and MRI study was designed to evaluate the effects and confer the mechanism of Class II with or without Temporomandibular joint internal derangement respectively treated with Herbst appliance,and distinguish the effects of the different situation of joint.Methods 1. We choose 52 cases of 10-22 years old in class II patients with mandibular retrusion divided into 3 groups. 26 cases of normal articular disc between condyle relationship patients(G1 group), 26 cases with TMJ ID patients(including 17 cases of simple application of Herbst appliance therapy, group G2; 9 cases of application of Herbst disc is reduction of auxiliary appliance joint treatment, group G3).Measuring the data on lateral cephalometric radiographs before and after treatment, We research the remodeling between the mandible, teeth and alveolar before and after treatment. 2. We choose 21 cases of 11-22 years old in class II patients with mandibular retrusion. divided into 3 groups. A total of 14 cases articular of disc-condyle relationship of 7 patients were normal(group H1); 10 cases of 5 patients with joint disorder without operation(group H2); 18 cases joint of 9 patients with internal derangement and articular disc replacement(group H3). Measuring the date of Joint MRI before and after treatment, We study the change of condyle, articular disc and glenoid fossa position,to explore the TMJ remodeling.ResultsAccording the cephalometric analysis,ANB 、OJ、0-Meridian-Pog’ were significantly reduced after treatment(P<0.05). Compared with the G3 group,G1 group of the length of the mandibular branch changes bigger. Compared with the G2 group, the Wits in G3 group have lager changes. According the measurement and analysis of MRI,H1 and H3 in condylar height value is larger, the difference was statistically significant(P<0.001);there was no significant difference in changes of condylar height and articular disc position of H2. Group H1 disc-condyle relationship and the condyle-fossa relationship were no significant differences; In H2 and H3 groups joint space index increased, with statistical difference(P<0.05). The disc-condyle relationship of group H3 have statistically significant different(P<0.001).Conclusions 1. Regardless of disc-condyle relationship is normal or not, the Class II malocclusion patients with mandibular retrusion of overjet, maxilla and mandible relative position, the soft tissue profile can be improved,after the Herbst appliance treament. But the disc-condyle relationship is normal, Herbst appliance on the mandibular position effect better. 2. Class II malocclusion patients with normal joint or with TMJ ID made disc replacement operation, the condylar growth increased significantly, after the Herbst appliance treament. For class II malocclusion patients with TMJ ID without operation, We did not find the absorption of condyle or the condylar growth significantly. 3. After the Herbst appliance treament,class II malocclusion patients with normal joint structure have no obvious changes in condylar position and disc position. Class II malocclusion patients with TMJ ID made operation group and non operation group, the condyle position was moved forward; Class II malocclusion patients with TMJ ID without operation group had no obvious change of articular disc position.