title: Risk of osteoradionecrosis after extraction of impacted third molars in irradiated head and neck cancer patients.
abstract: OBJECTIVE
  This study was performed to compare the risk of osteoradionecrosis (ORN) in head and neck cancer patients in whom 1 or more impacted third molars were extracted before radiotherapy with patients whose impacted third molars were left intact.
  
  
  METHODS
  Eighty-one patients were selected from the medical records from 1989 to 1998. Patients had at least 1 impacted third molar and received radiotherapy for a head and neck cancer. These patients were divided into 2 groups on the basis of preirradiation extraction: group 1, patients who had impacted third molars extracted before radiotherapy (n = 55), and group 2, patients whose impacted third molars were left intact before radiotherapy (n = 38). In 12 patients of combined groups 1 and 2, at least 1 but not all of the impacted third molars were extracted before radiotherapy.
  
  
  RESULTS
  Before radiotherapy, a total of 99 impacted third molars were extracted from the 55 patients in group 1 and a total of 55 impacted third molars were left intact in the 38 patients in group 2. After radiotherapy, a total of 7 impacted third molars were removed from 5 patients as treatment for infection (5 lower molars) or discomfort (2 upper molars). A total of 4 patients (2 from group 1 and 2 from group 2) developed ORN in the mandible. Of these 4 cases of ORN, 1 from group 1 appeared to be related to a dry socket that developed after preirradiation extraction of a lower impacted third molar, 1 from group 2 seemed to be related to infection of a lower impacted third molar after radiotherapy, and the remaining 2 cases appeared to be unrelated to an impacted third molar.
  
  
  CONCLUSIONS
  Because few patients in this study developed ORN, the study failed to demonstrate whether preirradiation extraction versus retention of impacted third molars affects the risk for ORN.
authors.affiliation: Department of Oral and Maxillofacial Surgery, College of Dentistry, Chonnam National University, South Korea. hkoh@chonnam.ac.kr
authors.forename: Hee-Kyun
authors.initials: HK
authors.lastname: Oh
authors.forename: Mark S
authors.initials: MS
authors.lastname: Chambers
authors.forename: Adam S
authors.initials: AS
authors.lastname: Garden
authors.forename: Pei-Fong
authors.initials: PF
authors.lastname: Wong
authors.forename: Jack W
authors.initials: JW
authors.lastname: Martin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015984:Causality; D002648:Child; D015897:Comorbidity; D016371:Cranial Irradiation / Q000009:adverse effects / Q000706:statistics & numerical data; D017742:Dental Care for Chronically Ill; D005260:Female; D006258:Head and Neck Neoplasms / Q000453:epidemiology* / Q000532:radiotherapy; D006801:Humans; D007568:Jaw / Q000473:pathology / Q000528:radiation effects; D007571:Jaw Diseases / Q000453:epidemiology*; D008297:Male; D008334:Mandible / Q000473:pathology / Q000528:radiation effects; D008875:Middle Aged; D008964:Molar, Third / Q000601:surgery; D010025:Osteoradionecrosis / Q000453:epidemiology*; D011878:Radiotherapy / Q000009:adverse effects / Q000706:statistics & numerical data; D012189:Retrospective Studies; D013781:Texas / Q000453:epidemiology; D014081:Tooth Extraction / Q000009:adverse effects / Q000706:statistics & numerical data*; D014095:Tooth, Impacted / Q000453:epidemiology / Q000601:surgery