Five weeks postoperatively, pain, drainage of purulent secretion, and bone exposure around the implants were observed (Fig. 4), although none of the implants showed mobility. Ten ozone therapy sessions associated with levofloxacin were performed. After 4 weeks of therapy with ozone oil (Philozon®, Balneário Camboriú, SC, Brazil), no pain or drainage of purulent secretion were present. Bone sequestration accompanied by implant mobility could, however, be seen. Local debridement and implant removal were performed.

The material removed consisted of 3 irregular fragments of hard, brown bone tissue, with the largest measuring 1.0 × 1.0 × 0.3 cm and the smallest measuring 0.4 × 0.4 × 0.3 cm. The material was stained with hematoxylin and eosin, and histological sections revealed irregular fragments consisting of devitalized bone and the presence of osteoclasts. Adjacent to the necrotic trabeculae, fibrous connective tissue exhibiting intense mixed inflammatory infiltrates (neutrophils, lymphocytes, plasma cells, and some macrophages) was found. Bacterial colonies and hemorrhagic foci were also noted (Fig. 5). Based on these results, the histological examination indicated osteonecrosis, categorized as stage 2 MRONJ [9].

At 14 days after debridement, the alveolar ridge was completely covered by soft tissue without bone exposure, and the patient was no longer experiencing pain. In March 2017, after the resolution of the osteonecrosis, the patient underwent the same chemotherapy regimen (bevacizumab, carboplatin, and docetaxel) as administered earlier. In July 2017, the patient was still undergoing chemotherapy. At the 7-month postoperative follow-up, the debrided area presented a healthy mucosal covering without lesions (Fig. 6). No signs of bone lysis or sequestration were seen on the panoramic radiograph (Fig. 7).