Periodontal vertical intrabony defects are an indication for regenerative treatment aimed at regenerating all structural elements of the periodontium. The prerequisite for success is adequate preparation of the patient for the procedure and the selection of the optimal regeneration strategy. In the case of intrabony defects which cannot be cleaned from the buccal side, elevation of gingival papilla is recommended. In the presented case, the procedure was carried out in accordance with the minimally invasive surgical technique (MIST). The root surfaces were cleaned with manual and ultrasonic devices and subsequently underwent biomodification using 24% EDTA and enamel matrix derivatives. The bone defect was filled with radiation-sterilized allogeneic bone, mixed with enamel matrix derivatives. Due to a thin phenotype, an autogenous subepithelial connective tissue graft was sutured under the buccal flap. Horizontal mattress sutures were used to close the wound. Sutures were removed after fourteen days. The final photos show the clinical situation six months after the procedure.