关键词: 牙弓宽度, 模型测量

Abstract: Objective The objective of the study is to obtain the data of the arch width of the children in Zhenghe，Fujian，and to know the development regularity and characteristics of the growth of the tooth. Methods The target of the study is 321 children who are between 3 and 9 years old in Zhenghe，Jianou， FuJian. We measured the arch width of dental model using calipers with digital and compasses and analyzed the data using SPSS 11.5. Results The sexual dimorphism of the arch width in most of groups divided by age and position was significant. Except for the arch width between mandibular permanent first molars， every position of the arch width in the groups of ＞7～9 years old was significantly larger than that of ＞5～7 years old. However， every position of the arch width had no significant differences between the groups of ＞5～7 years old and the groups of 3～5 years old， except that the arch width between maxillary deciduous canines in the groups of ＞5～7 years old was significantly larger than that of 3～5 years old. Conclusion The arch width significantly increases in the period of ＞7～9 years old. The changes is perhaps due to the eruption of incisors.

Key words: arch width, measurement of dental model