A dentist treats a patient with materials to compensate the lost tissue to recover the oral function. Regenerative medicine, which regenerates lost or mal-functioning tissues and organs, has been greatly concerned. The beginning of the regenerative medicine in dental field is that Dr. Hermann applied Ca(OH)₂ to pulp amputation in 1920. In 1980s GTR and GBR appeared and distraction osteogenesis has been applied in dental field. In the late 1990's, PRP for bone augmentation, Emdogain for periodontal tissue regeneration and rhBMP for bone augmentation were reported. Currently, clinical trial of FGF2 for periodontal tissue regeneration has been conducted. As cell-based therapy for regeneration, regeneration of mucous membrane, mandible and maxilla bones and periodontal tissues have been tried. Furthermore, the project of tooth regeneration has been started. In these circumstances, it should be noted that regenerative medicine is required effectiveness together with safety, simplicity and economical advantage.

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Three-dimensional (3D) microfabrication based on 3D measurements of the relevant microstructures has begun to be utilized in engineering various tissue and organs. We herein introduce some applications of existing 3D microfabrication processes in tissue engineering, that is, their applications in using biodegradable polymers or in making organ-structure-mimicking polymer scaffolds. In addition, we introduce our latest research regarding 3D design and fabrication of scaffolds suitable for liver tissue engineering that can be accessible to the blood circulation of patients. We point out that precise fabrication of inner micro-spaces of relevant organ is generally more important than that of the outer shape that has been considered important in conventional industrial applications.

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Using the human amniotic membrane (AM), we developed a novel material for cultivated mucosa epithelium cell and periodontal ligament cells (PDL) sheets. The objective of this study was to use the AM as an extracellular matrix (ECM) for culturing oral mucosa epithelium cells and PDL cells. After 2-3 weeks in culture, the cultivated epithelial cells showed five to seven layers stratification and well-differentiated cells and the cultivated PDL cells showed monolayer stratification on AM. Immunohistochemistry revealed that the cultivated epithelial cells expressed keratins 3, 4 and 13, but not keratins 1 or 10. We conclude that this novel material will be a useful new biomaterial for dentistry.

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To clarify the effect of inflammatory cytokines on the osteoblastic bone formation, we examined the extracellular matrix mRNA expression in the human osteoblast-like cells, SaOS-2, stimulated by interleukin-1beta (IL-1β) and/or tumor necrosis factor-alpha (TNF-α).
Quantitaive analysis using a real-time reverse transcriptase-polymerase chain reaction (RT-PCR) detection system demonstrated that IL-1β and TNF-α decreased the mRNA expression levels for alkaline phosphatase, type I collagen and osteocalcin but increased the mRNA expression levels for osteopontin and decorin in SaOS-2.
These results suggest that IL-1β and TNF-α suppress the extracellular matrix production by human osteoblast.

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Xenopus larvae were exposed to 2, 000 mg/l caffeine for 5 - 60 min just after hatching. The somites of the exposed larvae were affected and the larvae showed a wavy dorsal fin and abnormal body flexure. The body length of larvae in all exposed groups was significantly shorter than that of controls. The extent of shortening corresponded to the exposure time. Those caffine-exposed larvae were bred for 3 days in dechlorinated water. After breeding, the larvae exposed for 5 or 10 minutes did not differ from controls, but the body length of the larvae exposed for 30 minutes or more remained shorter than that of controls.

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In the concept of minimal intervention (MI), it is an urgent necessity for us to develop the new therapy of pulp capping and hard tissue regeneration. Recent studies showed the therapy using Ca(OH)2, or/and adhesive resins or some antibiotics mixture. In this study, to develop the new method of biological pulp capping, we used Connective Tissue Growth Factor (CTGF). To elucidate the ability of CTGF for cell proliferation and tissue mineralization, we immunohistologically analyzed the expression of osteonectin. Normal human pulp cells were stimulated by CTGF in culture medium for several hours, and analyzed the expression of osteonectin by immunohistochemical staining. Osteonectin, which is one of extra celluler matrix proteins and indicators of tissue mineralization, was expressed 96 hours after stimulation of CTGF. These results showed that CTGF is extremely useful for the establishment of the biological dentin regeneration therapy.

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