Relationship between tooth extraction and development of medication-related osteonecrosis of the jaw in cancer patients

Tooth extraction has been avoided since it has been considered a major risk factor for medication-related osteonecrosis of the jaw (MRONJ). However, MRONJ may also develop from tooth that is an infection source. This study aimed to clarify whether tooth extraction is a risk factor for the development of MRONJ in cancer patients receiving bone-modifying agents (BMAs). This retrospective observational study included 189 patients (361 jaws) from two hospitals. The risk factors of MRONJ were identified by comparing patient characteristics between those who did and did not develop MRONJ. Furthermore, the effect of tooth extraction during BMA therapy was analyzed after adjusting for confounding factors using the propensity score matching method. MRONJ occurred in 33 patients jaws. A longer duration of BMA administration, fewer number of teeth, presence of symptoms of local infection, and infected teeth were independent risk factors of MRONJ. However, tooth extraction during BMA therapy did not increase the risk. Propensity score matching analysis showed that tooth extraction significantly lowered the risk of MRONJ development. Teeth that can be an infection source increases the risk of MRONJ, and thus, they need to be extracted even during BMA administration.