1. Department of Oral and Maxillofacial Functional Rehabilitation, Graduate School of Medicine, University of the Ryukyus, Nishihara, Okinawa 903‑0215, Japan
2. Department of Oral and Maxillofacial Surgery, University Hospital of the Ryukyus, Nishihara, Okinawa 903‑0215, Japan
3. Department of Pathology, University Hospital of the Ryukyus, Nishihara, Okinawa 903‑0215, Japan