Male patient, healthy, 30 years old. In the position of the tooth #15 (4) was an inflammatory lesion without any pain or other clinical symptoms. We proposed apicoectomy of tooth #15 (4) but patient didn`t want this treatment. He returned with pain and swelling 6 months later. On the second x-ray we saw that the cyst was growing (including necrosis of the pulp in the tooth #14 (5) ). We did an endodontic treatment of #14 (5) and a surgery. The radicular cyst was removed (with histopathology), root resection of teeth #14 (5) and #15 (4) with retrograde MTA filling. We filled the bone defect with Bond Apatite® (1 cc). The patient reported medium pain and discomfort in the first two days after surgery. We observed good healing and bone remodeling 12 months post-op, without any inflammation. The patient reported no clinical symptoms.