The article presents a case report of the implantoprosthetic rehabilitation of an edentulous patient who underwent a mandibular tumour resection in the mental section due to squamous cell carcinoma of the floor of the oral cavity. The immediate postoperative defect was reconstructed with a microvascular free fibular flap. As part of the patient’s prosthetic rehabilitation, intraosseous implants were used, which is particularly advantageous in the group of edentulous patients undergoing mandibular resection procedures, where the functional conditions and topography of the prosthetic area exclude satisfactory stabilization of the prosthetic restoration. The process of adaptation to the new prosthetic restoration in the case of this patient was quick due to a radical improvement of their functioning. In particular, the lower overdenture showed a very satisfactory retention and stabilization on a prosthetic area. The applied implantoprosthetic treatment brought the expected clinical results and significantly improved the patient’s quality of life.