[Study on digital models of normal deciduous dentition in 189 children from Shanghai]

To study the gender difference and the regulation of growth and development in normal deciduous dentition． METHODS: A total of 189 children with normal deciduous dentition aged 3 to 6 years in several kindergartens in Xuhui District in Shanghai were selected. The three-dimensional(3D) digital dental models were reconstructed by intraoral scanning. Geomagic Studio, a 3D reverse engineering software, was employed to extract the data, such as the dental arc perimeter of C(APC), the dental arc perimeter of E(APE), the dental arc length of C(LC), the dental arc length of E(LE), the dental arc width of C(C-C), the dental arc width of E(E-E), the mesiodistal width of the deciduous crown, the maxillary and mandibular space. SPSS 22.0 software package was used for data analysis.

Parameters of deciduous dentition in boys were significantly elevated than in girls(P＜0.05). All the boys and girls were divided into 4 groups by age. In 3-year-old group, significant differences were observed in maxillary APC, C-C, E-E(P＜0.05) between boys and girls. In 4-year-old group, all boys' parameters were significantly greater than girls'(P＜0.05) except maxillary LC. In 5-year-old group, there were significant differences in all the parameters between boys and girl(P＜0.05) except maxillary APE and mandibular APC, LC, LE, C-C. No significant difference was observed in all the parameters except mandibular APE in 6-year old group. The significant difference between boys and girls were observed in the mesiodistal width of each deciduous crown except that of the maxillary lateral incisor and mandibular central incisor (P＜0.05). There were significant differences in maxillary LE and E-E among children of different ages(P＜0.05).The maxillary space was significantly greater than the mandibular space(P＜0.01).

There was gender difference in children's normal deciduous dentition, especially when they were 4 years old.