title: Comparison of nonexposed and exposed bisphosphonate-induced osteonecrosis of the jaws: a retrospective analysis from the Copenhagen cohort and a proposal for an updated classification system.
abstract: OBJECTIVE
  Nonexposed osteonecrosis of the jaws (NE-ONJ) does not fit into the current definition of osteonecrosis, which requires exposed bone. A modification of the classification of bisphosphonate-induced osteonecrosis of the jaws (ONJ) is proposed. This study aimed to test proposed criteria for NE-ONJ and compare NE-ONJ with exposed ONJ (E-ONJ) in a retrospective analysis.
  
  
  METHODS
  In 102 patients with E-ONJ diagnosed according to Ruggiero et al. (2006, 2009), criteria for NE-ONJ were developed. Subgroups of NE-ONJ and E-ONJ were tested against each other using nonparametric and parametric statistics.
  
  
  RESULTS
  Among 102 patients with ONJ, 14 had NE-ONJ and 88 had E-ONJ. NE-ONJ and E-ONJ were similar in all important data (P > .05) except bone exposure.
  
  
  CONCLUSIONS
  NE-ONJ belongs to the same disease condition as E-ONJ. NE-ONJ may be otherwise classified as ONJ stage 1, 2, or 3 and is different from ONJ stage 0. We propose to include the criteria for NE-ONJ into the classification.
authors: Consultant Oral and Maxillofacial Surgeon, Department of Oral & Maxillofacial Surgery, Rigshospitalet, University Hospital of Copenhagen, Copenhagen, Denmark. Electronic address: mschioedt@hotmail.com.
authors: Morten
authors: M
authors: Schiodt
authors: Professor, Section of Oral Medicine, Clinical Oral Physiology, Oral Pathology and Anatomy, Department of Odontology, University of Copenhagen, Copenhagen, Denmark.
authors: Jesper
authors: J
authors: Reibel
authors: Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University Hospital of Copenhagen, Copenhagen, Denmark.
authors: Peter
authors: P
authors: Oturai
authors: Head, Consultant Oral and Maxillofacial Surgeon, Department of Oral & Maxillofacial Surgery, Rigshospitalet, University Hospital of Copenhagen, Copenhagen, Denmark.
authors: Thomas
authors: T
authors: Kofod
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D059266:Bisphosphonate-Associated Osteonecrosis of the Jaw / Q000145:classification* / Q000453:epidemiology; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors