Harila Virpi, Heikkinen Tuomo, Alvesalo Lassi
Department of Oral Development and Orthodontics, Institute of Dentistry, University of Oulu, PL 5281, 90014 Oulu, Finland.
Early Hum Dev. 2003 Dec;75(1-2):9-20. doi: 10.1016/j.earlhumdev.2003.08.024.
The purpose of our study was to examine deciduous tooth crown size in preterm children.
The subjects consisted of 328 prematurely born (< 37 gestational weeks) white and black children and 1804 controls, who participated in the cross-sectional study of the Collaborative Perinatal Project (USA) in the 1960s and 1970s. Documents of the present research consisted of dental casts of the 6-12 years old children. Tooth crown measurements on canines and molars were performed on the dental casts with an electronic measuring device according to precise definitions generally quoted in the anthropological and genetic literature. For the results, the preterm and control groups were divided by sex and race.
There were both increased and decreased mesiodistal and labiolingual tooth crown dimensions in prematurely born children, but no significant differences between the study groups was found.
The findings of the present research suggest that short gestation is not associated with reduced deciduous tooth crown size as suggested by earlier studies and are parallel with our previous results of permanent tooth crown dimensions in prematurely born children. Boys showed clearly larger tooth crown sizes than girls within all preterm and control groups. This indicates that sexual dimorphism is apparent in its final form beginning some months after birth.
本研究旨在调查早产儿乳牙牙冠大小。
研究对象包括328名早产（孕周<37周）的白种和黑种儿童以及1804名对照儿童，他们参与了20世纪60年代和70年代美国围产期协作项目的横断面研究。本研究的资料包括6至12岁儿童的牙模。使用电子测量设备，根据人类学和遗传学文献中普遍引用的精确定义，对牙模上的犬齿和臼齿进行牙冠测量。结果方面，早产组和对照组按性别和种族进行划分。
早产儿的近远中径和唇舌径牙冠尺寸既有增加的情况，也有减小的情况，但研究组之间未发现显著差异。
本研究结果表明，与早期研究的结论相反，孕周短与乳牙牙冠尺寸减小并无关联，这与我们之前关于早产儿恒牙牙冠尺寸的研究结果一致。在所有早产组和对照组中，男孩的牙冠尺寸明显大于女孩。这表明出生后数月，性别二态性已呈现出最终的明显形态。
