Affiliation: | 1. Department of Oral and Maxillofacial Radiology, Peking University School and Hospital of Stomatology, Beijing, China;2. Department of Oral Radiology, Karolinska Institutet, Stockholm, Swedenkqgang@bjmu.edu.cn gangvanli@yahoo.com;4. Department of Periodontology and Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden;5. Department of Oral Radiology, Karolinska Institutet, Stockholm, Sweden |