Abstract: Objective To explore the rule of the dental development during deciduous dentition and to evaluate the applicability of Demirjian's method for dental age estimation on children during deciduous dentition,aged 4 to 6. Methods Through cluster sampling from kindergartens in Shenzhen,75 children aged 4-year-old (40 boys,35 girls) were chosen.The serial dental pantomograms,taken at ages 4,5 and 6 years old,were used for dental age assessment according to the Demirjian's method.The differences between dental age and chronological age were compared using paired t-test. Results Through 3-year growth,the second molar,the second premolar premolar,the first premolar premolar were at the stage of dental crown development,while the first molar,the canine,the lateral incisor and the central incisor at the stage of dental root formation.In terms of relative growth,female subjects exhibited an more mature teeth development than male subjects between 4 and 6 years old.A significant difference was found between chronological age and dental age. Conclusion Demirjian's method need to be modified to be used in dental age assessment on children during deciduous dentition.

Key words: deciduous dentition, dental age, Demirjian&apos, s method

摘要： 目的 观察乳牙列期儿童在4~6岁期间恒牙胚生长发育规律,探索Demirjian法在该群体牙龄研究的适用性。方法 在深圳市幼儿园小班随机抽取4岁左右汉族儿童75名(男童40名,女童35名),连续三年定期拍摄的全颌曲面断层X光片进行牙齿生长发育观察,并采用Demirjian法进行牙龄研究。结果 在4~6岁乳牙列期儿童第二磨牙、第二前磨牙和第一前磨牙处于牙冠发育阶段,第一磨牙、尖牙、侧切牙、中切牙处于牙根发育阶段。同龄女童的牙齿发育阶段显著领先于男童。除3.5~4.5岁组男童及4.5~5.5岁组女童的牙龄估计值与实际年龄差异无统计学意义外,各组提示Demirjian法评估值与实际年龄有差异(P<0.05)。结论 Demirjian法不能直接用于4~6岁乳牙列期儿童牙龄评估,后期需进一步扩大样本,探讨该年龄段儿童的牙龄评估曲线。

关键词: 乳牙列, 牙龄, Demirjian法