1. Department of Respiratory Disease, Zhongshan People's Hospital, Zhongshan, Guangdong 528403, P.R. China
2. Dental Implant and Restoration Centre, Zhongshan People's Hospital, Zhongshan, Guangdong 528403, P.R. China
3. The Second Department of Respiratory Disease, Jiangxi Provincial People's Hospital Affiliated to Nanchang University, Nanchang, Jiangxi 330006, P.R. China