Influence of induced infection in medication-related osteonecrosis of the jaw development after tooth extraction: A study in rats

Purpose: The mechanisms underlying the pathophysiology of medication-related osteonecrosis of the jaw (MRONJ) development have not yet been fully elucidated. MRONJ is described as a multi-factorial process in which bacterial infection seems to play an important role. The purpose of the present study was to investigate the influence of a primary installed infectious disease in the development of MRONJ after dental extraction. Materials and methods: Twenty-six rats underwent pulpal exposure of one upper and one lower first molar to induce periapical lesions. Thereafter, animals received zoledronate during a 4-week period. The day after the last injection, the four first molars from each quadrant were extracted. Eight weeks later, animals were sacrificed for macroscopic, radiological, and histological assessment. Results: The incidence of MRONJ was highest in mandibular infected teeth (47.4%), while the histological evaluation showed the highest incidence of osteonecrosis (88.2%) and the largest mean value for extent of the necrotic bone area (1.22 +/- 0.71 mm(2)). Radiological findings confirmed the clinical and histological results. Statistical analysis showed that the combination of both factors, mandibular localization and periapical infection, significantly increased the incidence of MRONJ after extraction, considering clinical (p = 0.0074), radiological (p = 0.026), and histological (p = 0.0022) outcomes. Conclusion: These findings support the potential implication of inflammatory/infectious dental pathology in initiating the osteonecrotic process before dental extraction. The possible partial role of the infectious process in MRONJ development emphasizes the importance of maintaining good oral health and dental care for preventing infectious pathology in the management of these patients. (C) 2018 Published by Elsevier Ltd on behalf of European Association for Cranio-Maxillo-Facial Surgery.