关键词: 牙根吸收, 拔牙

Abstract:

The study of apical root resorption following extraction therapy in adults and adolescents before and after orthodontic treatment. GUO Xin-xing*，CHEN Jing，ZHANG Yong.* Department of Orthodontics，Jinan Stomatological Hospital，Jinan 250001，China
Abstract： Objective To study the relationship between tooth movement and apical root resorption，and examine the relationship between root resorption and aging factors. Methods Thirty-four ClassⅠadolescent patients and thirty-six ClassⅠadult patients in middle mandibular angle were selected in Jinan Stomatological Hospital from July of 2004 to September of 2007; each patient was treated with straight wire mechanics and extracted the first premolar.The amount of apical root resorption of the central incisors and other items were measured for each patient by cephalograms Analysis & Database Winceph 8.0.Then the results were analyzed with Student's t-test. Result The apical root resorption happened in the lower central incisor of adolescents and the upper central incisor of the adults. There was a mean of 0.92 ± 1.19 mm of apical root shortening in adolescent patients， but in adult subjects the mean root resorption was 2.55 ± 1.60 mm. Conclusion The apical root resorption is prone to happen in the lower central incisor of adolescents and the upper central incisor of adults.Significant correlations are found between the amount of apical root resorption and tooth inclination， or the movement distance of the apical root.

Key words: root resorption, tooth extraction