Bisphosphonates are analogues of the natural compound pyrophosphate and one consequence of the mechanism of action of bisphosphonates on bone metabolism is the reduction of bone turnover, replenish the resorption spaces and to mineralize the extracellular matrix. Osteonecrosis of the jaw is the most common side effect of bisphosphonates and most often occurs after an invasive dental procedure, such as dental extraction. The existence of a maxillary bone infection leads to a delayed healing reaction manifested by the presence of areas necrotic bone, exposed in the oral cavity, which persists for more than eight weeks and has no tendency to heal. In most cases, the dentist is the first one who can detect the onset of osteonecrosis even in the early stages, thus being able to direct the patient to a hospital unit where he/she receives the treatment of necessity. The aim of this retrospective study is to determine the link between bisphosphonate therapy and the occurrence of necrosis of maxillary and mandibular bone. This study was conducted on 22 patients hospitalized for different stages of bone necrosis for a period of two years. The prevalence of osteonecrosis is higher in menopausal women and also after a certain period after the bisphosphonate therapy is closed.