Study examines jaw osteonecrosis in breast cancer patients

Dental Tribune International

Fri. 23. October 2026

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OULU, Finland: Anti-resorptive drugs are used to limit bone destruction, alleviate pain and reduce the risk of fractures in patients with advanced breast cancer. Because medication-related osteonecrosis of the jaws (MRONJ) is a recognised complication of these drugs, a recent nationwide study investigated the incidence of MRONJ and associated factors among Finnish patients with breast cancer and bone metastases, a population that had not previously been studied in Finland. The findings underscore the importance of dental and oncology professionals working together.

The retrospective study used data from two national healthcare registers and included 652 patients with breast cancer and bone metastases who had been prescribed anti-resorptive treatment during 2013–2015. The researchers followed their records until the end of 2020 and examined factors associated with MRONJ, including oral diseases, dental procedures and the type of anti-resorptive therapy prescribed—bisphosphonates, denosumab or both.

During follow-up, the incidence of MRONJ was significantly higher among patients treated with denosumab than among those treated with bisphosphonates. MRONJ was also more frequent among patients who had initially received bisphosphonates before switching to denosumab, although this association was not statistically significant after accounting for other factors. Overall, approximately one in eight patients were diagnosed with MRONJ during follow-up.

The study also found associations between MRONJ and dental procedures related to oral infections. Tooth extraction and root canal treatment showed particularly strong associations. Previous research has debated the role of oral infections and dental procedures in the development of MRONJ. The researchers of the current study suggested that the association with tooth extraction may reflect underlying oral infection and local inflammation. They noted that their findings were consistent with earlier evidence suggesting that local inflammation and impaired bone remodelling contribute to MRONJ development.

Lead author Dr Miika Kujanpää, a doctoral researcher at the University of Oulu, said in a university press release: “Our results highlight the importance of identifying and adequately treating potential sources of oral infection before starting anti-resorptive therapy, as well as monitoring oral health throughout treatment. This requires close collaboration between oncology and oral healthcare professionals.” An article published by Dental Tribune International similarly advocated for involving dental professionals in cancer care before cancer treatment begins.

Dr Kujanpää cautioned: “The findings alone do not warrant changing or discontinuing anti-resorptive treatment. Instead, the benefits and potential risks of treatment must be assessed on an individual basis. Nor should necessary dental treatment be withheld because of the associations observed.”

The researchers recommended that future studies should examine the timing of oral infections and dental procedures in relation to MRONJ onset to better understand the role of each factor and should investigate whether planned preventive oral healthcare can reduce the risk of MRONJ. They also emphasised the importance of long-term follow-up, since MRONJ can develop several years after anti-resorptive treatment.

The study, titled “Incidence and associated factors of medication-related osteonecrosis of the jaw in breast cancer patients with bone metastases: A nationwide registry study in Finland”, was published online on 29 September 2026 in Clinical Oral Investigations.