Gao, Xiaoli
Ding, Min
Xu, Mengru
Wu, Huijing
Zhang, Chunzi
Wang, Xing
Feng, Xiping
Tai, Baojun
Hu, Deyu
Lin, Huancai
Wang, Bo
Zheng, Shuguo
Liu, Xuenan
Rong, Wensheng
Wang, Weijian
Wang, Chunxiao
Funding for this research was provided by:
Scientific Research Fund of National Health Commission of the People’s Republic of China (201502002)
Article History
Received: 24 August 2019
Accepted: 24 December 2019
First Online: 8 January 2020
Ethics approval and consent to participate
: This study protocol was approved by the Stomatological Ethics Committee of the Chinese Stomatological Association, Beijing (No. 2014–003). A written informed consent form was sent to the parents of each child to explain the content of the survey. Each parent returned a signed.informed consent form.
: Not applicable.
: The authors declare that they have no competing interests.