At the Department of Oral-Maxillofacial Surgery, Dentistry, and Orthodontics, we provide various treatments focusing on surgical treatment for patients with diseases of the teeth, mouth, and jaws including congenital morphological defects such as cleft lip/cleft palate, jaw deformity, and injuries such as bone fracture, oral cancer, and infection. We also surgically reconstruct jawbone defects by inserting dentures or dental implants. Moreover, orthodontists correct malocclusions. We have directed special attention to advanced medical research and its clinical applications. In particular, in collaboration with the Department of Tissue Engineering, we have promoted the research and development of regenerative medicine of bone and cartilage and its clinical introduction (Figs. 1 and 2). Several representative examples have been included below.

Various surgical techniques for maxillofacial bone defects due to tumor resection or injury have been reported. Vascularized free fibula grafting has been increasingly used in particular for mandibular reconstruction requiring a long bone with sufficient blood flow. A surgeon needs to precisely adjust the shape of the bone graft, to ensure that it closely fits the grafting site during surgery. Because the maxillofacial region is complicated in shape and contour, a surgeon may find it difficult to achieve perfect restoration, which may ultimately affect patient satisfaction.
For such situations, we have recently introduced the bone restoration procedure using cancellous bone fragments collected from the ilium and a titanium mesh tray. In this procedure, the bone defect is filled with cancellous bone fragments and then covered with an appropriately shaped titanium mesh tray. This treatment enables the recovery of the natural shape and bone regeneration. Moreover, dentures or implants can be concomitantly inserted to restore proper occlusion. This regenerative approach may be ascribed to the body’s natural healing power.
Although this approach required sufficient experience to adjust and process the shape of the titanium mesh tray to that of the bone defect., recent development of a new mesh tray solved this problem. Unlike the conventional grid-like mesh tray, the new special hexagonal-pattern mesh tray allows quick 3-D processing without causing strain (Fig. 3).

Autogenous bone grafting causes stress on the bone donor site, and the amount of bone that can be collected is limited. In other countries, the cadaver bones are frequently used for transplantation. However, artificial bones are commonly used in Japan, in order to avoid the risk of infection and ethical concerns.
In collaboration with the School of Engineering at the University of Tokyo, we have used a 3-D ink-jet printer to develop a method for producing an artificial bone (CT-Bone) that matched the shape of the original bone. We have used CT images to produce a 3-D plaster model and to design the shape of the bone graft using wax. We subsequently used a 3-D ink-jet printer to produce an artificial bone (CT-Bone) with a shape that matched the wax bone (Fig. 4).
Currently, the CT-Bone is used to treat patients with depression/malformation of the face. In these patients, the CT-Bone provides excellent compatibility with the original bones, and its rapid fusion with the original bones has been confirmed.

Generally, cartilage has a very limited capacity for self-repair. A large amount of cartilage cannot be harvested from other regions of the body. Therefore, there are great expectations for the introduction of regenerative medicine technology that enables the artificial production of cartilage in chondrocyte cultures. To date, liquid- or gel-based regenerated cartilage has been available. However, this type of regenerated cartilage is not sufficiently hard to be used for the repair of serious facial malformations. We subsequently developed regenerated cartilage that could be used to repair a nose with sufficient hardness and an optimal shape.
A small amount of ear chondrocyte is cultured with blood collected from the patient. The collagen and special material containing absorbable plastic (scaffolding material) are subsequently combined to produce the “regenerated cartilage—known as the “implanted” regenerated cartilage because it is “surgically implanted” rather than injected. We collect a small amount of cartilage from behind the patient’s ear. The small cut made during this treatment prevents any noticeable scars or deformations (Fig. 5).