1. State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shanxi Key Laboratory of Stomatology; Department of Operative Dentistry and Endodontics; School of Stomatology; The Fourth Military Medical University; Xi'an China
2. Department of Operative Dentistry and Endodontics; School of Stomatology; The Guizhou Medical University; Guiyang China
3. Department of Stomatology; the Lishilu out-patient Department of the Chinese PLA Second Artillery Corps; Beijing China
4. Division of Restorative Dentistry and Periodontology; Dublin Dental University Hospital; Dublin Ireland
5. Oral Biology; School of Dentistry; University of Birmingham; Birmingham UK