1 School of Dentistry, Hospital of Stomatology, Tianjin Medical University, 12 Qi Xiang Tai Street, Heping District, Tianjin, 300070, China.
2 Institute of Biomedical Engineering, Academy of Medical Science and Peking Union Medical College, Tianjin, China.
3 Department of Histology and Embryology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China.
4 Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China.
5 School of Public Health, Tianjin Medical University, Tianjin, China.
6 School of Dentistry, Hospital of Stomatology, Tianjin Medical University, 12 Qi Xiang Tai Street, Heping District, Tianjin, 300070, China. enhai813@sina.com.
After publication of our article [1] we realized that we had not acknowledged that some of the text overlaps with a previous publication [2]. We apologize to readers for this error.