A comparison of extraction rates in two-phase versus one-phase Class II malocclusion patients

Introduction. Although the pros and cons of early two-phase treatment to correct Class II malocclusions have been examined, there is no study to date relating early growth modification techniques to final extraction rates and tooth position outcomes. Methods. Patients (n=61; age 6-17) were evaluated from a private orthodontic practice in Southern California; 41 patients were treated in a single phase, and 20 patients in two-phases. Full records were examined to compare (1) extraction rates in the permanent dentition and (2) final cephalometric numbers. Results. There was a 20% rate of premolar extraction in the two-phase group versus a 43.90% extraction rate in the single phase group (p=0.07). Final cephalometric numbers showed a significant difference in IMPA (p=0.05) with more flaring in the early treatment group, and no differences in ANB change. Conclusion. Early orthodontic intervention of Class II malocclusion resulted in reduced rates of premolar extractions with similar skeletal outcomes.