Comparison of premolar extraction rates between one-phase and two-phase class II malocclusion.

摘要

Introduction: The pros and cons of early two-phase treatment of Class II malocclusion have been examined recently. This study examines how growth modification will affect premolar extraction rates as well as final cephalometric outcomes.;Methods: Patients (n=46; ages 7-17) from a private practice of an American Board of Orthodontics diplomat in Southern California were evaluated. 27 patients were treated in a single-phase, and 19 were treated in two-phases. Full records of each patient were examined to compare premolar extraction rates in the permanent dentitions and resulting cephalometric measurements in single- and two-phase treatment groups.;Results: Out of the 27 patients undergoing single-phase treatment, 13 out of 27 (48.1%) required premolar extractions. 6 out of the 19 (31.6%) two-phase treatment patients needed extractions. Extraction rate between the two groups proved not to be significant. (p=0.261) Final cephalometric changes show no significant changes between the two groups.;Conclusions: Early orthodontic intervention in Class II malocclusion does not provide reduced rates in premolar extraction and does not affect cephalometric outcomes.