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Shozo Tagaki, Ph.D. Dr. Shozo Tagaki

Research interests

  • Calcium Phosphate Cement for hydroxyapatite and fluorapatite formation
  • Fluorapatite forming cement for endodontic application
  • Carbonated Hydroxyapatite Cement for Dosimetry
  • Remineralization of Dental Caries by Fluoride-Calcium-Phosphate Technology
  • Prevention of Dental Caries by Chewing Gum and Candies

Shozo Tagaki, Ph.D. Curriculum Vitae (PDF)

An active member of the scientific community, Dr. Takagi presented invited lectures in many international meetings, and was invited at Tokushima University and Nihon University (Japan) as a guest professor to be a mentor for their graduate students and faculties. He also collaborated with scientists from Japanese universities (Nihon University, Tokushima university, Tohoku University, Tokyo Medical Dental University) to work on calcium phosphate cement and fluoride-calcium-phosphate research. He was a co-worker with Dr. Chow, and their research was supported without interruption by NIH R01 and R21 grants (Co-principal Investigator) for three decades. Drs. Takagi and Chow’s patents for calcium phosphate cement licensed by Stryker brought $1.3 million of annual royalties to the ADA Foundation for many years.

Current research projects:

Carbonate Apatite Materials Based Biodosimetry

Dr. Shozo Tagaki Carbonate Apatite Materials graphDose determination of human tooth enamel using electron paramagnetic resonance (EPR) spectroscopy is an established technique for dose reconstruction in radiation accidents. This technology is based on the fact that ionizing radiation generates unpaired electrons proportional to the dose. In the case of tooth enamel, the unpaired electron species are extremely stable, persisting for decades or longer.

We have discovered a novel synthetic carbonated hydroxyapatite cement (CHC) material that exhibits spectrally clean (Fig 1) and highly reproducible EPR signals in proportion to the dose of radiation received. Preparation of the CHC materials is based on the chemistry similar to that of our previously developed self-hardening calcium phosphate cement materials that are currently used for bone defect repairs. Further, the CHC samples are chemically stable and have adequate mechanical strengths and surface integrity to be used as dosimeters.

CHC dosimeters can be fabricated under ambient conditions with highly reproducible EPR and other physical and chemical characteristics. It is anticipated that by modifying the cement compositions, CHC materials may be adapted for a wide dose range, high range for industrial applications; low range for personal dosimetry, or for a specific type of ionizing radiation, e.g., neutron radiation.

Selected Publications

  • Xu HH, Sun L, Weir MD, Takagi S, Chow LC, Hockey B (2007).  Effects of incorporating nanosized calcium phosphate particles on properties of wisker-reinforced dental composites.  J Biomed Mater Res Part B Appl Biomater 81(1):116-125.
  • Xu HH, Carey LE, Simon CG Jr, Takagi S, Chow LC (2007).  Premixed Calcium Phosphate Cements:  Synthesis, Physical Properties, and Cell Cytotoxicity. Dental Materials 23(4):433-441.
  • Vogel GL, Schumacher GE, Chow LC, Takagi S, Carey CM (2008). Ca Pre-rinse Greatly Increases Plaque and Plaque Fluid F. J Dent Res 87(5):466-469.
  • Sugawara A, Fujikawa K, Takagi S, Chow LC (2008).  Histological analysis of calcium phosphate bone grafts for surgically created periodontal bone defects in dogs. Dental materials journal 27(6):787-794.
  • Hirayama S, Takagi S, Markovic M, Chow LC (2008). Properties of calcium phosphate cements with different tetracalcium phosphate and dicalcium phosphate anhydrous molar ratios.  J Res Natl Inst Stand Technol 113:311-320.
  • Xu HHK, Weir MD, Sun L, Moreau JL, Takagi S, Chow LC, Antonucci JM (2010). Strong nanocomposites with Ca, PO4, F release for caries inhibition. J Dent Res 89(1):19-28.
  • Komabayashi T, Imai Y, Ahn C, Chow LC, Takagi S (2010). Dentin permeability reduction by a sequential application of calcium and fluoride-phosphate solutions. J Dent. 38(9):736-741.
  • Xu HH, Zhao L, Detamore MS, Takagi S, Chow LC (2010). Umbilical cord stem cell seeding on fast-resorbable calcium phosphate bone cement. Tissue Eng Part A. 16(9):2743-2753.
  • Vazquez D, Takagi, S, Frukhtbeyn S, Chow LC (2010). Effects of addition of mannitol crystals on the porosity and dissolution rates of a calcium phosphate cement. J Res Natl Inst Stand Technol 115:225-232.
  • Shimada Y, Chow LC, Takagi S, Tagami J (2010). Properties of injectable apatite-forming premixed cement. J Res Natl Inst Stand Technol 115:233-241.
  • Takagi S, Frukhtbeyn S, Chow LC, Sugawara A, Fujikawa K (2010). In vitro and in vivo characteristics of fluorapatite-forming calcium phosphate cements. J Res Natl Inst Stand Technol 115:267-276.
  • Sugawara A, Fujikawa K, Hirayama S, Takagi S, Chow LC (2010). In Vivo characteristics of premixed calcium phosphate cements when implanted in subcutaneous tissue and periodontal bone defects. J Res Natl Inst Stand Technol 115:277-290.
  • Chow LC, Takagi S (2014). Early history of the first calcium phosphate cement. JSDM, Vol 34 No. 3.
  • Suzuki Y, Hayash M, Yasukawa T, Kobayashi H, Makino K, Yoriyuki Hirano Y, Takagi S, Chow LC, Ogiso B (2015). Development of a novel fluorapatite-forming calcium phosphate cement with calcium silicate: In vitro and in vivo characteristics. Dental Materials Journal, Vol 34, No.2, p263-269.
  • Suzuki Y, Hayashi M, Tanake N, Tsurumachi T, Yasukawa T, Hirano Y, Takagi S, Chow LC, Suzuki N, Ogiso B (2015). Effect of a novel fluorapatite-forming calcium phosphate cement with calcium silicate on osteoblasts in comparison with mineral trioxide aggregate. Journal of Oral Science, Vol 57, No. 1, p25-30.

Patents (relevant patents from total of 32)

  • Chow LC, Takagi S, U.S. Patent No. 5 522 893, Calcium phosphate hydroxyapatite precursor and methods for making and using the same, June 4, 1996.  
  • Chow LC, Takagi S, U.S. Patent No. 5,525,148, Self-setting calcium phosphate cements and methods for preparing and using them, June 11, 1996.
  • Chow LC, Takagi S, U.S. Patent No. 5,695,729, Calcium phosphate hydroxyapatite precursor and methods for making and using the same, December 9, 1997.
  • Chow LC, Takagi S, Vogel GL, U.S. Patent No. 5,993,786, Anti-carious chewing gums, candies, gels, toothpastes and dentifrices, November 30, 1999.
  • Chow LC, Takagi S, Vogel GL, U.S. Patent No. 6,491,900, Anti-carious candies and confections, December 10, 2002.
  • Chow LC, Takagi S, U.S. Patent No. 6,793,725, Premixed calcium phosphate cement pastes, September 21, 2004.
  • Chow LC and Takagi S, U.S. Patent No. 7,709,029, Calcium-containing Restoration Materials. US Patent No. 7,709,029, May 4, 2010.
  • Chow LC and Takagi S, U.S. Patent No. 8,557,038, Dual-phase calcium phosphate cement composition, October 15, 2013.
  • LC Chow and S Takagi, U.S. Patent No. 8956594, Fluoride-calcium compositions, dental products, and methods for providing dental fluoride, February 17, 2015.
  • LC Chow and S Takagi, U.S. Patent No. 9101436, Dental and endodontic filling materials and methods, August 11, 2015.

Mentor to Ph.D. dissertation

  • Ogata, Hidehiro:  In vitro properties of fluorapatite-forming calcium phosphate cements, 2011 (Nihon University Dental School, Tokyo, Japan)

Postdoctoral Associates in the last 10 years

  • Dr. Debra Vasquez (Naval Postgraduate Dental School)
  • Dr. Hiromichi Iizuka (Japanese Navy Dental Corp)
  • Dr. Yasushi Shimada (Tokyo Medical and Dental University)
  • Dr. Go Inoue (Tokyo Medical and Dental University)

External Collaborating Principle Investigators in the last 10 years

  • Dr. Marc Desrosiers, National Institute of Standards and Technology
  • Dr. Joseph Antonucci, National Institute of Standards and Technology
  • Dr. Hockin H Xu, University of Maryland Dental School
  • Dr. Akiyoshi Sugawara, Nihon University Dental School, Tokyo, Japan
  • Dr. Amani Mostafa, National Research Center, Cairo, Egypt
  • Dr. Takashi Komabayashi, Baylor College of Dentistry, Dallas, TX
  • Dr. Satoshi Hirayama, Nihon University Dental School, Matsudo, Japan
  • Dr. Makoto Hayashi, Nihon University Dental School, Tokyo, Japan