title: Dental status, dental treatment procedures and radiotherapy as risk factors for infected osteoradionecrosis (IORN) in patients with oral cancer - a comparison of two 10 years' observation periods.
abstract: OBJECTIVE
  Dental status, dental treatment procedures and radiotherapy dosage as potential risk factors for an infected osteoradionecrosis (IORN) in patients with oral cancers: Retrospective evaluation of 204 patients treated in two observation periods of approximately ten years each.
  
  
  METHODS
  In group A, 90 patients were treated in the years 1993-2003, in group B 114 patients in the years 1983-1992 (data in brackets). All patients had histopathologically proven squamous cell cancers, mainly UICC stages III and IV. 70% (85%, n.s.) had undergone surgery before radiotherapy. All patients were referred to the oral and maxillofacial surgeon for dental rehabilitation before further treatment. Radiotherapy was performed using a 3D-conformal technique with 4-6MV photons of a linear accelerator (Co-60 device up to 1987). The majority of patients were treated using conventional fractionation with total doses of 60-70 Gy in daily fractions of 2 Gy. Additionally, in group A, hyperfractionation was used applying a total dose of 72 Gy in fractions of 1.2 Gy twice daily (time interval > 6 hours). In group B, a similar schedule was used up to a total dose of 82.8 Gy (time interval 4-6 hours). 14 (0) patients had radiochemotherapy simultaneously. After therapy, the patients were seen regularly by the radiooncologist and - if necessary - by the oral and maxillofacial surgeon. The duration of follow-up was 3.64 years (5 years, p = 0.004).
  
  
  RESULTS
  Before radiotherapy, the dental health status was very poor. On average, 21.5 (21.2, n.s.) teeth were missing. Further 2.04 teeth (2.33, n.s.) were carious, 1.4 (0.3, p = 0.002) destroyed. Extractions were necessary in 3.6 teeth (5.8, p = 0.008), conserving treatment in 0.4 (0.1, p = 0.008) teeth. After dental treatment, 6.30 (4.8, n.s.) teeth remained. IORN was diagnosed after conventionally fractionated radiotherapy in 15% (11%, n.s.), after hyperfractionation in 0% (34%, p = 0.01).
  
  
  CONCLUSIONS
  Within more than 20 years there was no improvement in dental status of oral cancer patients. Extensive dental treatment procedures remained necessary. There was an impressive reduction of the IORN frequency in patients treated in a hyperfractionated manner probably resulting from a dose reduction and an extension of the interfraction time.
authors.affiliation: Department of Cranio-and-Maxillo Facial Surgery, Düsseldorf University Medical School, Düsseldorf, Germany.
authors.forename: Marcus
authors.initials: M
authors.lastname: Niewald
authors.affiliation: Department of Oral and Maxillofacial Surgery, Saarland University Medical Center, Homburg/Saar, Germany.
authors.forename: Kristina
authors.initials: K
authors.lastname: Mang
authors.affiliation: Department of Cranio-and-Maxillo Facial Surgery, Düsseldorf University Medical School, Düsseldorf, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Barbie
authors.affiliation: Department of Cranio-and-Maxillo Facial Surgery, Düsseldorf University Medical School, Düsseldorf, Germany.
authors.forename: Jochen
authors.initials: J
authors.lastname: Fleckenstein
authors.affiliation: Department of Oral and Maxillofacial Surgery, Saarland University Medical Center, Homburg/Saar, Germany ; Department of Cranio-and-Maxillo Facial Surgery, Düsseldorf University Medical School, Düsseldorf, Germany.
authors.forename: Henrik
authors.initials: H
authors.lastname: Holtmann
authors.affiliation: Department of Oral and Maxillofacial Surgery, Saarland University Medical Center, Homburg/Saar, Germany.
authors.forename: Wolfgang J
authors.initials: WJ
authors.lastname: Spitzer
authors.affiliation: Department of Cranio-and-Maxillo Facial Surgery, Düsseldorf University Medical School, Düsseldorf, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Rübe
keywords: Dental status; Infected osteoradionecrosis; Oral cancer; Radiotherapy