Medication-related osteonecrosis of the jaw around dental implants: Implant surgery-triggered or implant presence-triggered osteonecrosis?

Introduction: Dentoalveolar surgery including tooth extractions and dental implants placement is considered the major risk factor for developing medication-related osteonecrosis of the jaw (MRONJ). In this study, a patient series of MRONJ around dental implants were carefully analyzed to describe the findings and to assess the possible risk factors. Methods: Fifteen patients with peri-implant bone osteonecrosis were selected out of a group of 250 patients (6%). Patients were divided into 2 groups according to the temporal relationship. Group 1 (G1)-necrosis immediately after implant placement (from 2 to 10 months) and defined as "implant surgery-triggered" MRONJ. Group 2-necrosis distant (from 1 to 15 years) from implant placement and defined as "implant presence-triggered" MRONJ. Epidemiological and pharmacological variables were recorded as well as specific data about osteonecrosis and dental implants. Results: G1 included 6 patients: 5 (83.4%) treated with oral bisphosphonates (BPs) for osteoporosis and 1 (16.6%) with intravenous BPs for breast cancer. Mean duration of BP therapy (BPT) was 83.7 months. G2 included 9 patients: 8 patients (88.89%) treated with intravenous BPs for malignant disease and 1 (11.11%) with oral BPs for osteoporosis. Conclusions: Data confirms that not only surgical insertion of dental implants is a potential risk factor for the development of osteonecrosis but also the presence itself of the implant into the bone can be associated with this disease. Therefore, it is necessary to informof the increased risk for MRONJ also the patients who have already osteointegrated implants and are going to start the BPT. The risk is lower for patients receiving oral BPs but it exists and seems to be higher if the implant is located in the posterior areas, if the duration of BPT is more than 3 years and if the patient is under corticosteroid therapy.