Clinical and Epidemiological Characteristics of Retrospective Single-Center Observational Study.

Background: Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a severe adverse event associated with antiresorptive therapy, particularly bisphosphonates, and represents a significant challenge in oral and maxillofacial practice. This study aimed to characterize the epidemiological profile, clinical presentation, and anatomical distribution of bisphosphonate-related osteonecrosis of the jaw (BRONJ) and to investigate potential associations between demographic variables and major underlying systemic diseases. Methods: A retrospective single-center observational study was performed using medical records collected between January 2020 and December 2025 at the Emergency County Clinical Hospital of Craiova. After data validation and removal of duplicate records, 121 patients diagnosed with osteonecrosis of the jaw were identified. Among them, 94 patients fulfilled the inclusion criteria for BRONJ and were included in both the statistical and clinical analyses. Demographic characteristics, systemic diseases, bisphosphonate therapy, lesion localization, clinical manifestations, and statistical associations were evaluated using appropriate non-parametric and categorical statistical methods. Results: The final analytical sample comprised 94 patients with BRONJ associated with bisphosphonate therapy. Of these, 75 (79.8%) had received bisphosphonates for malignant disease and 19 (20.2%) for osteoporosis. The mandible was affected in 77% of patients, predominantly in the posterior premolar-molar region, whereas maxillary lesions mainly involved the posterior maxilla and maxillary tuberosity. Exposed necrotic bone was identified in all patients, while purulent discharge and oral fistulas were recorded in 37% and 35% of cases, respectively. Associations involving sex, age, residence, diabetes, hypertension, and other comorbidities were re-evaluated using the final 94-patient cohort. Conclusions: Among the BRONJ cases identified at this referral center, most patients had received bisphosphonate therapy for malignant disease, and lesions showed a marked predilection for the mandible, particularly its posterior region. These findings describe the clinical profile of the cases managed at our institution but do not permit estimation of BRONJ incidence or comparative risk between treatment regimens. The results support careful dental assessment before bisphosphonate therapy and multidisciplinary follow-up of patients receiving antiresorptive treatment.