**5.7 Anatomical factors**

It is known that medication related osteonecrosis occurs more often in the lower jaw in 73% of cases relative to the upper jaw, where it occurs in 22.5% of cases, while the incidence of osteonecrosis in both jaws simultaneously only in 4.5% of cases [3]. It also turned out that MRONJ more often develops in places with the thinnest layer of mucosa, and these are the lingual side of the lower jaw and the various exostoses and toruses found in the oral cavity [3, 47]. Wearing a prosthesis is also doubling the risk of developing MRONJ.
