Needs and current research directions of biological regenerative medicine in prosthodontic practice--to attain reliable and sophisticated dental implant therapy

Appropriate dental implants are known to improve the quality of life in totally and partially edentulous patients, as well as to prevent future tooth loss, and so prosthetic treatment modalities have drastically changed recently with reconstruction therapy. However, dental implant therapy did not win the confidence of the dental community in the early developmental stage, until osseointegration between titanium and surrounding bone tissue was discovered and the modality utilizing osseointegration became reliable and produced durable treatment outcomes for long-term function. On the other hand, the biological mechanism of osseointegration has not been clarified yet and the time required for osseointegration is still long, e.g. three to four months. As well, when the implant is applied in the upper posterior region, the acquisition of osseointegration and the long-term survival of the implant are still not clinically adequate. Therefore, to reduce the time required for osseointegration and to regenerate enough alveolar bone mass in the target implantation site, the oral implant modality must be made more useful and potent as one of the treatment options for partial and total edentulism. With this background, we have studied biological strategies for reducing the time required for osseointegration and for regenerating enough alveolar bone mass, e.g., investigation of the specific genes for osseointegration between titanium and bone, nano-level surface modification of the titanium, biodegradable apatite foam for alveolar bone regeneration, application of bone formation-related growth factors with biological scaffold, and autologous cell transplantation of bone marrow derived mesenchymal stem cells. In this article, we review the current status of regenerative medicine being applied in prosthodontics and discuss our future research direction.