Obtaining better outcomes from guided bone regeneration techniques often re-quires the use of ideal membranes. The objective of this study was to develop a novel membrane and investigate its contribution to the enhancement of bone regeneration. The membrane was fabricated by combining β-TCP particles with dissolved gelatin hydrogel and cross-linking molecules with glutaraldehyde. Rat bone-marrow cultured on this gelatin membrane for 14 days revealed time-dependent cell proliferation and the presence of alkaline-phosphatase-positive cells as well as that on a collagen membrane. Histological analysis indicated that significantly more new bone volume was generated in symmetrical full-thickness bone defects of rat calvariae covered by the gelatin membrane compared to that of the uncovered control defects at 4 and 8 weeks post operation. The present study demonstrates that the novel β-TCP-containing gelatin hydrogel membrane stimulates bone regeneration. These results suggest the feasibility of this novel membrane for use in guided bone regeneration.
The zeta potential of the surface of anatase-form titania particles modified by ultraviolet (UV)-irradiation or cold-plasma O2 treatment was investigated and compared with that of unmodified titania particles. Zeta potential was first determined after suspension in 10 mM sodium chloride and then with exposure to various concentrations of sodium hydroxide. The charge shifted from positive with a low pH to negative and finally zero with increase in pH. The pH of the solution at which the zeta potential was zero was determined as the isoelectric point (pI). The pI of unmodified titania particles was 6.5. After UV-irradiation, the pI shifted with increase in alkalinity (pI=9.2). Cold-plasma O2 modification of the titania particles also yielded a shift in pI with increase in alkalinity (pI=8.9). These findings showed that physicochemical surface modification of anatase-form titania particles by UV-irradiation or cold-plasma O2 treatment resulted in a change in surface charge. This indicates that such treatment could be used to control adsorption and desorption of specific molecules to titania surfaces. Further research is needed, however, to determine the applicability of such treatment to other metals. These findings are useful in controlling the physicochemical nature including the surface electrical charge, and in surface modification of the titanium scaffolds for tissue engineering.
VEGF is known to play a significant role in microangiopathy through AGEs. The objective of this study was to observe the expression and distribution of VEGF and AGEs immunohistochemically in the early healing stage of periodontal defects in model rats with type 2 diabetes (GK), and then clarify the relationship between these expressions and microangiopathy in the healing process. We surgically prepared periodontal defects in the maxillary molars of male 30-week-old GK and SD rats. On Days 3, 5, and 7 after surgery, the rats were euthanized. The periodontal samples were stained immunohistochemically with anti-VEGF and anti-AGE monoclonal antibodies. AGEs and VEGF were more significantly observed in the GK rats than in the SD rats around blood vessels. These results suggest that, in the GK rats under-going periodontal surgery, AGEs localized around capillary blood vessels contribute to an intensive expression of VEGF compared to the SD rats, and then VEGF causes microangiopathy during wound healing.
We have proposed the embryotoxicity testing of mouse ES cells embedded in a collagen gel matrix. The rate of differentiation of ES-D3 cells into cardiomyocytes was measured using a glass fiber as a scaffold material for collagen gel. In order to design a test method for embryotoxicity under an exposure condition where broader applications would be possible in various fields using a glass fiber as a non-animal-derived scaffold material. We measured as the test materials using TEGDMA, EGDMA and 2HEMA. There was no significant difference found with glass fiber and collagen gel matrix. Therefore, it was suggested that glass fiber could be used as the scaffold material for in vitro embryotoxicity test. Furthermore; the Embryonic Stem Cell Test may be able to apply to the environmental field etc.
The mechanical strength of the scaffold to ensure space for jaw bone augmentation is needed. In the present study, we focused upon massive shaped coral, with its large volume consisting of superficial and deep parts. Porous coral (massive Porites) was used. The surfaces of the internal cavities of the coral were observed using SEM. The specific gravity and the physical strength of the deproteinized coral blocks under wet condition were measured. Particles of coral were added into culture cells and the cell proliferation and differentiation into blood capillaries of the coral were studied. The ducts with 100-200 μm were interconnected and opened to the outside. The surface of the exoskeleton was covered with numerous porous processes 1 μm in diameter. The specific gravity and compressive strength of the superficial layer of the coral were 1.30 and 29.1 MPa, and those of the deep layer were 1.45 and 36.3 MPa, respectively. The coral particles induced cell proliferation and differentiation into blood capillaries. These findings suggest that this coral would be useful as scaffolding material for bone augmentation.
A questionnaire was conducted on foreign residents living in the Kyoto-Osaka area during the summer of 2011. The participants were asked about their experiences at dental clinics in Japan and the impressions that were made. Among the responses, it was discovered that a sense of privacy was important for foreign patients and the English communication skills of the dentists appeared to be generally poor. However, the use of visual aids to explain the treatment procedures proved to be helpful in making up for the language deficiencies. Many commented that the showing of a sincere effort to communicate, regardless of English ability, was encouraging and would help in building rapport. Unfortunately, there appeared to be a lack of knowledge concerning regenerative medicine though most showed interest in including it as part of their treatment at dental clinics. The results of the survey implies that in order to answer the needs of foreign patients, there is a necessity to introduce specific conversational skills and topic/vocabulary development to the English classes at dental schools. Assimilation of these skills and incorporating visual aids in the classroom along with improved curriculum would prove to be more effective for the student's study of practical dental English.
Various studies on regeneration have been performed in the regenerative dental field, but very few results have actually been clinically applied, and many new ideas have already been disregarded. In the Japanese regenerative dental field, some original ideas were favorably evaluated, but many were a reworking of studies performed in other countries, and the contents were mostly combinations or slight modifications of preceding studies. It may be time to return to the starting point and reconsider the study objective. To overcome this situation, studies based on original ideas not performed in other countries may be initially necessary to promote regenerative dental research in Japan.