Lower second molar extraction in correction of severe skeletal class III malocclusion.
The purpose of this study was to evaluate dentoskeletal and soft-tissue profile changes after extraction of lower second molars and treatment using the Tip-Edge technique in severe Class III subjects. Thirteen patients with severe skeletal Class III malocclusion (four males, nine females), diagnosed as requiring orthognathic surgery, but who rejected surgical therapy, were included in the study. The average age was 13.2 +/- 0.8 years. Lateral cephalometric films taken at the beginning and the end of treatment were analyzed using the Pancherz analysis and a traditional cephalometric analysis. The arithmetic mean and standard deviation were calculated for each variable. Paired t-test was performed to evaluate significant treatment change. After active treatment, dramatic overjet change was noted, with an average value of 5.5 mm (P < .001). Inclination of lower incisors was decreased 12.0 degrees when measured to the mandibular plane (P < .001). Inclination of upper incisors was increased by 2.1 degrees to the SN plane (P > .05). A negative value of the distance between upper and lower lip position to Sn-Pg' at the beginning of treatment changed to a positive value (P < .001). The results of this preliminary study suggest that success in the treatment of some severe Class III deformity in the permanent dentition can be achieved with fixed appliances and extraction of lower second molars. A remarkable soft-tissue change was noted after the treatment, and concave facial profiles changed to straight profiles.
Lin
Jiuxiang
J
Department of Orthodontics, School of Stomatology, Peking University, Bejing, People's Republic of China. jxlin@pku.edu.cn
Gu
Yan
Y
D000293:Adolescent; D002508:Cephalometry / Q000379:methods; D002648:Child; D005145:Face / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008046:Lip / Q000033:anatomy & histology; D008297:Male; D008313:Malocclusion, Angle Class III / Q000601:surgery*; D008963:Molar / Q000601:surgery*; D008964:Molar, Third; D009971:Orthodontics, Corrective / Q000295:instrumentation / Q000379:methods*; D011859:Radiography; D014081:Tooth Extraction