Biphosphonate-associated maxillary bone osteonecrosis (BPMO) is a complication related to nitrogen-containing biphosphonate therapy. This adverse effect occasionally appears in patients who are administered biphosphonates through intravenous infusion for the treatment of cancer involving bone metastases. It can also present, in a lesser degree, in patients who take these drugs orally for the treatment of osteoporosis. Lately, there has been an increase in the number of cases of osteopenia and osteoporosis due to the increasing life expectancy of the world's population. In our country, a risk group composed mainly of older women who have been diagnosed with osteopenia or osteoporosis, and submitted to the continuous action of oral biphosphonates, is emerging. In this paper we present 18 cases of BPMO associated to the use of oral biphosphonates, diagnosed and treated in the Department of Stomatology of the School or Dentistry at Universidad Nacional de Rosario, Argentina. A protocol was designed in which the following information was recorded: age and sex of the patients, the original disease which led to therapy with oral biphosphonates, the drugs used and the period in which those drugs were administered, the clinical features and location of the lesions, together with triggering factors.