中文摘要：

目的对成都地区青少年第三磨牙牙龄与年龄的相关性进行研究。方法选择2009-2011年于四川大学华西口腔医院正畸科就诊的青少年患者，拍摄全景片，参照Demirjian法的牙龄判断标准对左下颌第三磨牙发育情况进行分期。对不同性别第三磨牙的发育程度进行成组设计t检验分析，对第三磨牙发育程度与生理年龄的关系进行Spearman相关分析。结果在Demirjian分期为A期时，不同性别第三磨牙的发育程度有统计学差异P=0．026），男性发育早于女性。Spearman相关分析表明：男性、女性及总体样本的生理年龄与第三磨牙发育程度均有相关性（男性r=0．808，P=0．000；女性r=0．729，P=0．000；总体r=0．760，P=0．000）。年龄（X）和第三磨牙发育程度（Y）的相关回归方程为：Y总体=4．898＋2．036X；Y男性=4．987＋2．046X；Y女性=4．819＋2．036X。结论第三磨牙发育程度可以作为推断青少年生理年龄的一个可靠指标。

英文摘要：

Objective To investigate the relationship between the stages of calcification of the third molar and age among children in Chengdu. Methods The study subjects consisted of children between 2009 and 2011 at the Department of Orthodontics, West China Hospital of Stomatology, Sichuan University. Panoramic radiographs were ob- tained. The stages of calcification of the third molar were analyzed by Demirjian＇s method. The development of the third molar between the male and female was evaluated by independent samples t-test analysis. The Spearman rank correlation was applied to analyze the stages of calcification of the third molar and chronological age. Results The development of the third molar of the male was different from that of the female at stage A of calcification of the third molar（P=0.026）. The Spearman rank correlation coefficient revealed highly significant relationships between the stages of calcification of the third molar and chronological age of the three groups （male, r=0.808, P=O.O00; female, r= 0.729, P=O.O00; all, r=0.760, P=O.O00）. Furthermore, the linear regression equations were established as follows： Yall= 4.898＋2.036X; Ymale=4.987＋2.046X; Yfemale=4.819＋2.036X. ConclusiOn The stages of calcification of the third molar may be an available indicator in judging chronological age of teenager.