A retrospective study on odontogenic and non-odontogenic medication-related osteonecrosis of the jaw: Potential differences in clinical features and treatment outcomes

Abstract

Background/purpose: Local infections, such as periodontal disease or apical lesions, and invasive dental procedures, such as tooth extraction, are thought to trigger medication-related osteonecrosis of the jaw (MRONJ) development. However, some cases of MRONJ develop without any obvious odontogenic triggers. We conducted a retrospective study to clarify the characteristics of non-odontogenic MRONJ.

Materials and methods: We retrospectively reviewed data of 229 patients with mandibular MRONJ who underwent surgery. Based on imaging findings, we classified MRONJ as odontogenic MRONJ involving a dental infection and non-odontogenic MRONJ with no dental involvement. Clinical and imaging findings and treatment outcomes of both types of MRONJ were compared.

Results: Overall, 193 patients were classified as having odontogenic MRONJ and 36 as having non-odontogenic MRONJ. Non-odontogenic MRONJ was slightly more common among patients with malignancies who received denosumab; however, the difference was not significant. Univariate and multivariate analyses showed that patients with MRONJ with non-odontogenic triggers had significantly poorer treatment outcomes than their counterparts.

Conclusion: Non-odontogenic MRONJ exists without the involvement of odontogenic infection as a cause of MRONJ. Compared with that in odontogenic MRONJ, the treatment outcome in non-odontogenic MRONJ is poor. Further studies are required to clarify the true nature of non-odontogenic MRONJ.

Keywords: Infection; MRONJ; Non-odontogenic; Odontogenic; Trigger.

Figure 1

Odontogenic MRONJ. Osteolysis and sequestrum separation were seen in continuity with the periapical radiolucent area. A: panoramic X-ray, B: CT of frontal sections, C: CT of axial sections.

Figure 2

Non-odontogenic MRONJ. A, B: There was an ulceration under the denture base that reached the bone, and a radiolucent area was seen from the alveolar surface to the upper mandibular canal. C, D: There was no bone exposure or fistula in the oral cavity, but a cutaneous fistula was found in the lower jaw. There was no tooth with a source of infection and no osteolysis in the alveolar region, but there was extensive periosteal reaction at the inferior margin of the mandible.

Figure 3

The cumulative cure rate of the all patients. Three-year cure rate was 84.0 %.

Figure 4

Factors related to the treatment outcome. Along with malignancy and mixed-type osteosclerosis, non-odontogenic trigger was associated with poor treatment outcome.