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Raman spectroscopy is based on Raman scattering of light form molecules, and Raman spectra provide highly useful information about molecular composition and its circumstances. The micro FT-Raman spectra both of ghost cells in calcifying cystic odontogenic tumor and keratinocytes of the gingiva showed a broad beak centered around 850 cm-1.

Signaling pathways have been shown to participate in the process of Retinoic acid (RA) - induced cleft palate (CP). In our current study, the signaling molecules of GSK-3 beta, Fzd3 and beta-TrCP, which all relate with Wnt pathway, were screened from the palate tissues of the RA-induced CP in mice by the Gene-chip Technology. But, their expression pattern and level in palates during perinatal stages have not been known yet. In the studies, mRNA level of GSK-3 beta, Fzd3 and beta-TrCP were detected by quantitative real-time PCR, and showed significant difference between the Embryonic day 18 (ED18) before birth and Postnatal day 0 (PD0) after birth, as well as between the RA-induced CP and wild type during the perinatal stage, respectively. And the localization pattern of GSK-3 beta, Fzd3 and beta-TrCP proteins in palates was also characterized. Our data indicates that the Wnt signaling pathway may involve in the RA-induced cleft palate during peirnatal stage.

Tooth enamel is composed of nano-scale, needle-like biological apatite crystallites. These crystallites constitute the enamel prisms. The generally accepted Meckel's model of arrangement of crystallites in enamel prism might be slightly revised according to the variations in tooth enamel chemical composition and structures. An x-ray diffraction method was proposed to survey the three-dimensional crystallite orientation instead of electron microscopy. Preliminary results showed clear difference in the convergence and broadening of enamel crystallite orientations of human tooth enamel. This method has high potential in analyzing partial deviation in crystallite orientation as well as easy sample preparation and operation.

Parametric X-ray (PXR) is a new type of radiography with variable monochrome wavelength and high coherent characteristics. The Laboratory for Electron Beam Research and Application (LEBRA) at Quantum Science Institute, Nihon University generated LEBRA-PXR, a system that irradiates Si crystal with electron accelerated by linear accelerator (LINAC). LEBRA-PXR is uniquely developed for world-wide application experiment. X-ray images of tooth samples were taken with flat panel detector using LEBRA-PXR. As a result, images were captured as short as 1 sec. LEBRA-PXR uses LINAC with micro-macro pulse electron beam structure. Imaging time of 1 sec is equivalent to about 0.025 msec when x-ray is converted to actual radiation exposure. The effective dose point estimates of x-rays were about 1 μ Sv/5 sec. Results show that LEBRA-PXR can be used to generate low dose x-ray imaging advocating the possibility of its application in biological studies and medical treatment.

Wavelength-tunable monochromatic Parametric x-ray (PXR) was generated at the Laboratory for Electron Beam Research and Application (LEBRA) at Nihon University. Using the LEBRA-PXR, phase contrast imaging was carried out. Phase contrast images of a kitten deciduous tooth were taken by diffraction enhanced imaging (DEI) method. The results showed that LEBRA-PXR is a high coherent x-ray and is suitable for phase contrast imaging.

Wavelength tunable Free Electron Laser, FEL, was irradiated onto the polished surfaces of human tooth enamel and dentin using the FEL system at Laboratory for Electron Beam Research and Application (LEBRA) in Nihon University. LEBRA-FEL system was so powerful that only 2 mJ/pulse shot resulted in an apparent pit on the surfaces. The pit showed neither marked scorch nor formation of secondary crystalline phase revealed by micro-XRD and micro-FTIR. Optimum wavelength for pit formation on the dental hard tissues was about 3.0 mm. However, the optimum wavelengths for enamel and dentin should be at 3.2 mm, 3.0 mm, respectively. The results strongly suggested that the ablation mechanism by laser irradiation for dental hard tissues might be not the simple interaction of laser beams with water, but complex phenomena, which could not be neglected of the hard tissue components and structure.