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Oral Ecology and Biochemistry


Continually moistened with saliva, the oral cavity is made of various soft and hard tissues, such as teeth, gingiva and the tongue, and is the pathway of foods to enter the body. In addition, a tremendous number of microorganisms inhabit there in the form of oral biofilm (or dental plaque). The oral cavity forms an ecosystem where the host (humans) and parasites (microorganisms) cohabit. Disruption of balance of this healthy oral ecosystem leads dental caries, oral malodor and periodontal diseases.

Using leading-edge techniques of molecular biology, anaerobic experimental systems and the notion of "omics", we conduct research on the role of oral biofilms in oral health and disease from an oral ecosystem viewpoint. In addition, we propel clinical research on caries-preventive effects of xylitol, fluoride etc, and on parasite-caused degradation of biomaterials. As for research close to our everyday life, we evaluate cariogenicity of food products and provide the information to the society through governmental agencies. Recently, we have also started conducting research on the metabolism of cancer cells which exhibit a similarity to parasites.

Healthy coexistence of the host and the parasites is what ultimately leads to good oral health. Through research on our symbiotic partners (parasites), the Division of Oral Ecology and Biochemistry is aiming to improve and preserve oral health. We boast a healthy and cooperative atmosphere with a wide diversity of students coming from such fields as nutrition management, pharmacology and, of course, dentistry.

Faculty configuration

  • Prof.Nobuhiro TakahashiProf.Nobuhiro Takahashi

Topics of Research

  • Genomics, proteomics and metabolomics of oral microbial ecosystem (oral biofilm)
  • Metabolism and pathogenicity of microorganisms associated with dental caries, periodontal disease and oral malodor, using an anaerobic experimental system
  • Caries preventive properties of fluorides/sugar alcohols and evaluation of cariogenic potential of food products and sweeteners using pH-telemetry
  • Oral biofilm-induced deterioration of dental biomaterials
  • Metabolomics of oral cancer cells

Recent Performance

  1. Ishiguro T, Mayanagi G, Azumi M, Otani H, Fukushima A, Sasaki K, Takahashi N: Sodium fluoride and silver diamine fluoride-coated tooth surfaces inhibit bacterial acid production at the bacteria/tooth interface. J Dent. 2019 (in press).
  2. Fukushima A, Mayanagi G, Sasaki K, Takahashi N: Corrosive effects of fluoride on titanium under artificial biofilm. J Prosthodont Res 62(1): 104-109, 2018.
  3. Morishima H, Washio J, Kitamura J, Shinohara Y, Takahashi T, Takahashi N: Real-time monitoring system for evaluating the acid-producing activity of oral squamous cell carcinoma cells at different environmental pH. Sci Rep 7(1): 10092, 2017.
  4. Mayanagi G, Igarashi K, Washio J, Takahashi N: pH Response and Tooth Surface Solubility at the Tooth/Bacteria Interface. Caries Res 51(2): 160-166, 2017.
  5. Yamamoto Y, Washio J, Shimizu K, Igarashi K, Takahashi N: Inhibitory Effects of Nitrite on Acid Production in Dental Plaque in Children 15(2): 153-156, 2017.
  6. Washio J, Ogawa T, Suzuki K, Tsukiboshi Y, Watanabe M, Takahashi N: Amino acid composition and amino acid-metabolic network in supragingival plaque. Biomed Res 37(4): 251-7, 2016.
  7. Takahashi N, Nyvad B: Ecological Hypothesis of Dentin and Root Caries. Caries Res 50(4): 422-31, 2016.
  8. Tian L, Sato T, Niwa K, Kawase M, Mayanagi G, Washio J, Takahashi N: PCR-dipstick DNA chromatography for profiling of a subgroup of caries-associated bacterial species in plaque from healthy coronal surfaces and periodontal pockets. Biomed Res 37(1): 29-36, 2016.
  9. Washio J, Takahashi N. Metabolomic studies of oral biofilm, oral cancer, and beyond. Int J Mol Sci. 17(6). pii: E870, 2016.
  10. Kawashita M, Endo N, Watanabe T, Miyazaki T, Furuya M, Yokota K, Abiko Y, Kanetaka H, Takahashi N. Formation of bioactive N-doped TiO2 on Ti with visible light-induced antibacterial activity using NaOH, hot water, and subsequent ammonia atmospheric heat treatment. Colloids Surf B Biointerfaces. 145:285-290, 2016.

Laboratory Contacts

E-mail:OEB*dent.tohoku.ac.jp (Please change * to @.)