[1] Natl Univ Singapore, Fac Dent, Singapore, Singapore
[2] Univ Amsterdam, Acad Ctr Dent Amsterdam, Dept Oral Med, Gustav Mahlerlaan 3004, NL-1081 LA Amsterdam, Netherlands
[3] Vrije Univ Amsterdam, Gustav Mahlerlaan 3004, NL-1081 LA Amsterdam, Netherlands
[4] Univ Groningen, Univ Med Ctr Groningen, Dept Radiat Oncol & Oral & Maxillofacial Surg, POB 30-001, NL-9700 RB Groningen, Netherlands
[5] Carolinas HealthCare Syst, Dept Oral Med, POB 32861, Charlotte, NC 28232 USA
[6] Kaiser Franz Josef Spital, Inst Radioonkol, Vienna, Austria
[7] Univ Amsterdam, Acad Med Ctr, Dept Oral & Maxillofacial Surg, Amsterdam, Netherlands
[8] Univ Athens, Sch Dent, Clin Hosp Dent, Athens, Greece
[9] Univ Basel, Univ Ctr Dent Med Basel, Dept Prevent Dent & Oral Microbiol, Basel, Switzerland
[10] Aarhus Univ, Dept Dent & Oral Hlth, Vennelyst Blvd 9, DK-8000 Aarhus C, Denmark
[11] Univ Copenhagen, Dept Odontol, Oral Med, Norre Alle 20, DK-2200 Copenhagen N, Denmark
[12] North East Canc Ctr, Dent Oncol Program, Hlth Sci North, 41 Ramsey Lake Rd, Sudbury, ON P3E 5J1, Canada