Parenteral Ozone Therapy Combined with Topical Antimicrobials Enhances Tissue Repair in Mandibular Osteonecrosis of Elderly Female Rats

Medication-related osteonecrosis of the jaws (MRONJ) remains a challenging complication associated with antiresorptive therapy, highlighting the need for effective adjunctive preventive strategies. This study evaluated the effects of systemic ozone therapy, alone or combined with topical 10% metronidazole paste or 2% chlorhexidine gel, on alveolar repair in a zoledronate-induced rat model of MRONJ. Forty-two ovariectomized female Wistar rats were allocated into seven experimental groups. Following mandibular first molar extraction, animals received systemic ozone therapy and/or topical antimicrobial treatment according to the experimental protocol. Clinical, histomorphometric, micro-computed tomography (micro-CT), Picrosirius Red, and immunohistochemical analyses were performed. Zoledronate treatment markedly impaired alveolar repair, resulting in reduced new bone formation, increased non-vital bone, epithelial disorganization, and unfavorable bone microarchitecture. Systemic ozone therapy significantly increased new bone formation and improved bone microstructural parameters compared with untreated zoledronate animals. Ozone-treated groups also exhibited more organized collagen fibers and increased VEGF and osteocalcin immunostaining. Topical metronidazole and chlorhexidine were associated with favorable tissue repair findings, while combined therapies showed more favorable outcomes than zoledronate treatment alone. These findings suggest that systemic ozone therapy, particularly when associated with topical antimicrobial treatments, improves alveolar repair and represents a promising adjunctive strategy for preventing MRONJ.