The Effects of Quick Self-ligating System on Enlarging Maxillary and Alveolar Arch

［Abstract］Objective　To analyze the effects of self-ligating bracket on enlarging the maxillary alveolar arch and to investigate the the non-extraction treatment programs. Methods　All patients were used heat activated basic and precise theory for the orthodontist in order to make a plan fordeveloping nickel-titanium wire， then assessed by occlusalplane analysis method. The maxillary model andcephalometric radiographs were collected and measured before the treatment. The data of the resultswereanalyzed．Results　After the treatment， the increase of the width of the dental arch was related to the ∠FMA， crowding degree and canines initial position. The increase of arch length was related to the ∠ANB， crowding degree，malocclusion classification， canines initial position andthe second molar eruption．Conclusion　The essential factors include the crowding degree of arch， ∠FMA， ∠ANB， the angle of the anterior teeth，malocclusion classification，canines initial position andthe second molar eruptioncan affect the result of non-extraction quick self-ligating bracket appliance treatment on enlarging the maxillary alveolar.