The purpose of this article was to overview the writer’s research methods and activities in regenerative dentistry;　First, introduction of computer simulations of bone remodeling using the finite element method based on Wolff's law, surgical guidance using 3D modeling (Additive Manufacturing), novel measurement technique using MRI, mechanical property measurement of living soft tissues, and the international standardization activities for devices in regenerative medicine.

Regenerative medicine aims to return damaged organs or tissues to their normal state using various regenerative techniques. Several decades have already passed since the idea of tissue engineering appeared in the 20^th century. It has been pointed out that all three factors, cells, scaffolds and signaling molecules, are necessary for organ or tissue regeneration. In the field of dentistry, hard tissues such as teeth and alveolar bone and soft tissues such as gingiva and oral mucosa are targeted for regeneration. In addition, the oral cavity contains various salivary gland tissues, and saliva is also a major regeneration target. Since the sense of taste is related to the health and nutrition of the whole body, recovery of the taste buds is an important regeneration target. In the field of dentistry, it has been common practice to restore tooth function through prosthetic treatment. Dental engineers have developed biomaterials that are aesthetically pleasing and have sufficient mechanical strength for prosthetic treatment.

There are great expectations for regenerative medicine techniques that do not use biomaterials to join conventional prosthetic treatment. This time, I will describe the contents of regenerative medicine based on the above three factors, and add the contents specific to dental regeneration.

Our research group grasps dentin caries treatment from both "induction of decalcified dentin remineralization" and "induction of reparative dentin formation in deep-seated caries." It studies dentin remineralization/regeneration from each approach to developing a functional restorative material, thereby providing the dentin-pulp complex with self-restoration capacity. The resin monomer CMET developed by our group is a highly functional monomer capable of remineralization induction, dentin regeneration, and anti-biofilm formation, exhibiting a promising material for functional material development. Based on these findings, new bioactive coating material and universal bonding agent have been developed. Further improvement of these materials will enable caries prevention and self-repair of infected and demineralized dentin in sealed restorations, which is the ideal caries treatment. This will ultimately change caries treatment from "cutting and restorative" to "self-restorative."

Department of Restorative Dentistry and Endodontology, Research Field in Dentsitry, Medical and Dental Sciences Area, Research and Education Assembly, Kagoshima University, Japan

Kagoshima University Hospital, one of advanced treatment hospitals, provides daily medical treatment with the aim of offering advanced medical care. The Department of Restorative Dentistry and Endodontology also conducts various clinical studies, and several studies are currently in progress. Mineral Trioxide Aggregate (MTA) is extremely useful in conservative dentistry because of its ability to induce hard tissue, and various MTA-based materials are available in Japan. We focused on the application of one of these materials, a resin-modified-type MTA material using tributylborane as a polymerization initiator, for a retrofilling material in apicoectomy.

Dramatic improvements in computer processing speeds have made elaborate predictions and modelling possible, but to what extent are the results correct? This presentation will introduce several types of biomechanical simulations and discuss the researchers' own understanding, which is becoming more important than in the past in order to obtain reliable qualitative or quantitative results.

Metal implants such as titanium alloy and stainless steel, or biodegradable polymeric implants such as polyglycolic acid and polylactic acid are commonly used for the born fracture treatment. However, removal surgery of metal implants after fracture healing are required that increase the burden on patients. On the other hand, polymeric implants do not require a removal surgery, but their strength are not enough.

To resolve such issues, we focused on magnesium is an essential element and good bioabsorbability in the human body. In particular, high-purity magnesium does not contain alloying elements which are a target for biological safety consideration. Moreover, in vitro test showed the biodegradation period can be adjusted approximately 8 to 12 weeks or longer, and the strength can be maintained by controlling the purity, crystal grain size, and crystal orientation. The safety of magnesium implants will be confirmed and established through biological safety tests and clinical trials.

This review introduces the cryoprotectants and cryoprotection methods that have been reported so far. In particular, polymer-based cryoprotectants, which have been actively studied in recent years, are outlined, from their mechanisms of action to their application in regenerative medicine.