title: Osteonecrosis associated with dental implants in patients undergoing bisphosphonate treatment.
abstract: OBJECTIVE
  Bisphosphonate-related jaw necrosis (BRONJ) associated with dental implants is a rare but continuously reported complication. To verify clinical and pathological characteristics of BRONJ around dental implants, the present study analyzed clinical, radiographic and histopathological findings of these lesions.
  
  
  METHODS
  Nineteen patients were diagnosed with osteonecrosis of the jaw associated with dental implants and treated at our institute from 2008 to 2011. The patients' medical history, demographic features, radiographic, and histopathological findings along with information on bisphosphonates (BP) administration were analyzed.
  
  
  RESULTS
  The majority of BRONJ patients associated with dental implants used oral BP for osteoporosis. The patients were divided into two groups: BP initiation before (n = 16) and after (n = 3) implant surgery. Only three patients (15.8%) could be regarded as "implant surgery-triggered" BRONJ. Many patients (n = 9) showed successful osteointegration after fixture installation to an average of 35 months (11-82 months) until the development of osteonecrosis. The histological features of the lesion showed that the necrotic bone with empty lacunae was infiltrated by inflammatory cells and bacterial colonies. Viable osteocytes were also observed in some areas of the bony specimens. Three types of bone destruction pattern were observed: (i) complete necrosis of the bone around the implant (frozen type), (ii) extensive osteolysis around the implant with or without sequestra (osteolytic type), and (iii) sequestration of bone with an implant maintaining direct implant-bone contact (en block sequestration type). These findings could be existed at the same lesions depending on the degree of local bone destruction and the severity of the infection.
  
  
  CONCLUSIONS
  These results and those of others suggested that already osseointegrated dental implants can also cause the osteonecrosis around the implant after BP administration. En block sequestration of bone with implant might be one of the characteristics of implant-related BRONJ, which is different from peri-implantitis-induced bone destruction. The possible role of microcracks in this type of bone destruction needs to be examined further.
authors.affiliation: Department of Oral & Maxillofacial Surgery, School of Dentistry, Kyungpook National University, Daegu, Korea.
authors.forename: Tae-Geon
authors.initials: TG
authors.lastname: Kwon
authors.forename: Chung-O
authors.initials: CO
authors.lastname: Lee
authors.forename: Jin-Woo
authors.initials: JW
authors.lastname: Park
authors.forename: So-Young
authors.initials: SY
authors.lastname: Choi
authors.forename: Girdhari
authors.initials: G
authors.lastname: Rijal
authors.forename: Hong-In
authors.initials: HI
authors.lastname: Shin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D059266:Bisphosphonate-Associated Osteonecrosis of the Jaw / Q000000981:diagnostic imaging / Q000209:etiology* / Q000601:surgery; D015921:Dental Implants / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011862:Radiography, Panoramic; D011877:Radionuclide Imaging; D014057:Tomography, X-Ray Computed
chemical_list: D015921:Dental Implants
keywords: bisphosphonates; dental implants; jaw; osteonecrosis