抄録
Due to their improved success rate, there has recently been a large increase in the use of dental implants. Several types have been imported from foreign countries in order to obtain improved masticatory function and esthetics. In addition, in the field of maxillofacial surgery here in Japan certain implant materials such as Co-Cr, titanium, ceramics and other artificial materials have been applied together with autogenous bone grafts for reconstruction of the mandible following excision of tumors. The criterion for success is essentially the same whether for mandibular reconstruction or for a preprosthetic dental implant in that they both must provide oral rehabilitation and comfort for the patient.
Satisfactory, long-term results cannot be obtained in every case due to postoperative infection, the exposure of the implant to intra- and extra-oral sites, and resorption of the underlying grafted bone. For these reasons we have carried out reconstruction of the mandible with a vascularized osteomyocutaneous flap using a microvascular anastomoses technique to reconstruct large defects and prevent bone resorption. Nonetheless, even when the reconstruction has been successful, postoperative problems such as difficulties with mastication, deglutition, and speech often remain due to the loss of soft tissues and teeth, and due to deformities of the alveolar ridge and contours of the mandible.
Attempts have therefore been made in reconstruction of the edentulous mandible in certain countries to apply various dental implants which eliminate these postoperative dysfunctions. The Transmandibular (TM) Implant devised by Dr. Hans Bosker of the Netherlands is one such device. We were the first in Japan to apply this implant to the reconstruction of two mandibles resected due to oral carcinomas.
The first case reconstructed a segmentally resected mandibular defect with revascularized iliac bone. The second case involved a mandible which was marginally resected due to a tumor. Both cases were reconstructed with major flaps such as a deltopectoral flap combined with a pectoral major myocutaneous flap, and a forearm flap for soft tissue defects at the primary surgery. Both of the TM-Implant cases showed significant elimination of oral dysfunction due to the stability of the dentures placed during the second phase of treatment.
Dental implants can be expected to improve function for the patients who have had surgery for oral carcinomas. In order to avoid postoperative complications when implants are performed, it is necessary to carry out careful surgical procedures as well as careful diagnosis of the pre-operative condition of the bone using periapical and panoramic radiographs, tomography, CT, MRI, and bone scintigraphy. In addition, since the perfect dental implant system has as yet not been developed, it is very important to the future development of dentistry that each practitioner maintain detailed records of all of his cases.
