Kyushu University Academic Staff Educational and Research Activities Database
List of Papers
Kunio Ishikawa Last modified date:2020.09.29

Professor / Oral Rehabilitation / Department of Dental Science / Faculty of Dental Science


Papers
1. Kunio Ishikawa, Melvin L. Munar, Kanji Tsuru, Youji Miyamoto, Fabrication of carbonate apatite honeycomb and its tissue response, Journal of Biomedical Materials Research - Part A, 10.1002/jbm.a.36640, 107, 5, 1014-1020, 2019.05, Carbonate apatite (CO 3 Ap) block can be used as a bone substitute because it can be remodeled to new natural bone in a manner conforming with the bone remodeling process. Among the many porous structures available, honeycomb (HC) structure is advantageous for rapid replacement of CO 3 Ap to bone. In this study, the feasibility to fabricate a CO 3 Ap HC was studied, along with its initial tissue response in rabbit femur bone defect. First, a mixture of Ca(OH) 2 and a wax-based binder was extruded from a HC mold. Then the fabricated HC was heated for binder removal and carbonation at 450°C in a mixed O 2 –CO 2 atmosphere, forming a CaCO 3 HC. When the CaCO 3 HC was immersed in 1 mol/L Na 3 PO 4 solution at 80°C for 7 days, its composition changed from CaCO 3 to CO 3 Ap, maintaining the structure of the original CaCO 3 HC. Compressive strengths of the CaCO 3 and CO 3 Ap HCs were 65.2 ± 7.4 MPa and 88.7 ± 4.7 MPa, respectively. When the rabbit femur bone defect was reconstructed with the CO 3 Ap HC, new bone penetrated the CO 3 Ap HC completely. Osteoclasts and osteoblasts were found on the surface of the newly formed bone and osteocytes were also found in the newly formed bone, indicating ongoing bone remodeling. Furthermore, blood vessels were formed inside the pores of CO 3 Ap HC. Therefore, CO 3 Ap HC has good potential as an ideal bone substitute..
2. Vilma Jonauske, Sandra Stanionyte, Shih Wen Chen, Aleksej Zarkov, Remigijus Juskenas, Algirdas Selskis, Tadas Matijosius, Thomas C.K. Yang, Kunio Ishikawa, Rimantas Ramanauskas, Aivaras Kareiva, Characterization of Sol-Gel derived calcium hydroxyapatite coatings fabricated on patterned rough stainless steel surface, Coatings, 10.3390/COATINGS9050334, 9, 5, 2019.05, Sol-gel derived calcium hydroxyapatite (Ca10(PO4)6(OH)2; CHA) thin films were deposited on stainless steel substrates with transverse and longitudinal patterned roughness employing a spin-coating technique. Each layer in the preparation of CHA multilayers was separately annealed at 850 °C in air. Fabricated CHA coatings were placed in simulated body fluid (SBF) for 2, 3, and 4 weeks and investigated after withdrawal. For the evaluation of obtained and treated with SBF coatings, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), X-ray diffraction (XRD) analysis, Raman spectroscopy, XPS spectroscopy, scanning electron microscopy (SEM) analysis, and contact angle measurements were used. The tribological properties of the CHA coatings were also investigated in this study..
3. Inga Grigoraviciute-Puroniene, Aleksej Zarkov, Kanji Tsuru, Kunio Ishikawa, Aivaras Kareiva, A novel synthetic approach for the calcium hydroxyapatite from the food products, Journal of Sol-Gel Science and Technology, 10.1007/s10971-019-05020-4, 91, 1, 63-71, 2019.07, In this study, for the synthesis of calcium hydroxyapatite (Ca10(PO4)6(OH)2; CHAp), an environmentally-friendly water-based sol–gel chemistry approach using food products as calcium and phosphorus precursors has been developed. In the sol–gel processing, the food products having the greatest calcium and phosphorus concentrations and the calculated calcium and phosphorus molar ratio closest to Ca/P = 1.67 were selected as starting materials (hard cheese “Dziugas”, preserved Atlantic sardines in oil, low-fat yogurt “Dobilas”, and pumpkin seeds). The synthesis products were investigated by thermal analysis (TG/DTG-DSC), infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD) analysis, and scanning electron microscopy (SEM). The content of Ca and P in the food products was determined by means of ICP-OES. [Figure not available: see fulltext.]..
4. Koichiro Hayashi, Melvin L. Munar, Kunio Ishikawa, Carbonate apatite granules with uniformly sized pores that arrange regularly and penetrate straight through granules in one direction for bone regeneration, Ceramics International, 10.1016/j.ceramint.2019.05.042, 45, 12, 15429-15434, 2019.08, Artificial bone substitutes that can solve the problems associated with autogenous bone grafts are essential. In this study, macroporous carbonate apatite (CO3Ap) granules with the same composition as natural bone were implanted into distal epiphysis defects in rabbit femurs. Material resorption and bone regeneration were then evaluated. The macroporous granules were obtained by extruding honeycomb (HC) structure rods containing calcium hydroxide, pulverizing the rods to granules, carbonating them to calcite, and converting them from calcite to CO3Ap. Notably, the HC-type macropores fully penetrated and spanned their diameters of the CO3Ap granules in one direction, as well as being regularly arranged and uniformly sized (120 μm). They facilitated cell penetration into the granules and the induction of angiogenesis. As a result, bone remodeling occurred simultaneously within the granules and on the granule surfaces. Furthermore, the granules were gradually resorbed and replaced by bone. Thus, introducing HC-type macropores into granules is an effective approach for promoting bone regeneration..
5. Inga Grigoraviciute-Puroniene, Yuhei Tanaka, Visata Vegelyte, Yuko Nishimoto, Kunio Ishikawa, Aivaras Kareiva, A novel synthetic approach to low-crystallinity calcium deficient hydroxyapatite, Ceramics International, 10.1016/j.ceramint.2019.05.072, 45, 12, 15620-15623, 2019.08, Synthetic calcium deficient hydroxyapatite (CDHA, with the formula Ca9(HPO4)(PO4)5OH) is a promising material which could be potentially used in biomedicine. The aim of this study was to develop a simple and cost-effective synthesis route for the preparation of low crystalline CDHA granules. A method based on an incessant dissolution-precipitation reaction eventually resulting in a solid and shaped material consisting of the desired phase was utilized. The calcium sulphate hemihydrate was selected as the starting material. The synthesis products obtained were characterized by Fourier transformed infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). The monophasic calcium deficient hydroxyapatite granules of about 300–350 μm in diameter were synthesized by three slightly different preparative approaches at 70 °C temperature and compared. Independently of the composition of the raw granules synthesized ones were composed of low crystalline an apatitic phase. The granules were calcium deficient as contained HPO4 2− group in their structure. It was demonstrated that the addition of (NH4)H2PO4 or (NH4)2HPO4 into the raw granules could promote the growth of the CDHA crystallites. SEM revealed that the microstructure of synthesized materials was influenced by the chemical composition of the raw granules. Chemical composition and presence of no an X-ray amorphous phase in obtained samples was confirmed by reheating the obtained granules at 800 °C to get monophasic β-TCP. Our work provides a novel and simple approach to produce CDHA granules for various applications..
6. K. Hayashi, R. Kishida, A. Tsuchiya, K. Ishikawa, Honeycomb blocks composed of carbonate apatite, β-tricalcium phosphate, and hydroxyapatite for bone regeneration
effects of composition on biological responses, Materials Today Bio, 10.1016/j.mtbio.2019.100031, 4, 2019.09, Synthetic scaffolds exhibiting bone repair ability equal to that of autogenous bone are required in the fields of orthopedics and dentistry. A suitable synthetic bone graft substitute should induce osteogenic differentiation of mesenchymal stem cells, osteogenesis, and angiogenesis. In this study, three types of honeycomb blocks (HCBs), composed of hydroxyapatite (HAp), β-tricalcium phosphate (TCP), and carbonate apatite (CO3Ap), were fabricated, and the effects of HCB composition on bone formation and maturation were investigated. The HC structure was selected to promote cell penetration and tissue ingrowth. HAp and β-TCP HCBs were fabricated by extrusion molding followed by sintering. The CO3Ap HCBs were fabricated by extrusion molding followed by sintering and dissolution-precipitation reactions. These HCBs had similar macroporous structures: all harbored uniformly distributed macropores (∼160 ​μm) that were regularly arrayed and penetrated the blocks unidirectionally. Moreover, the volumes of macropores were nearly equal (∼0.15 ​cm3/g). The compressive strengths of CO3Ap, HAp, and β-TCP HCBs were 22.8 ​± ​3.5, 34.2 ​± ​3.3, and 24.4 ​± ​2.4 ​MPa, respectively. Owing to the honeycomb-type macroporous structure, the compressive strengths of these HCBs were higher than those of commercial scaffolds with intricate three-dimensional or unidirectional macroporous structure. Notably, bone maturation was markedly faster in CO3Ap HCB grafting than in β-TCP and HAp HCB grafting, and the mature bone area percentages for CO3Ap HCBs at postsurgery weeks 4 and 12 were 14.3- and 4.3-fold higher and 7.5- and 1.4-fold higher than those for HAp and β-TCP HCBs, respectively. The differences in bone maturation and formation were probably caused by the disparity in concentrations of calcium ions surrounding the HCBs, which were dictated by the inherent material resorption behavior and mechanism; generally, CO3Ap is resorbed only by osteoclastic resorption, HAp is not resorbed, and β-TCP is rapidly dissolved even in the absence of osteoclasts. Besides the composition, the microporous structure of HC struts, inevitably generated during the formation of HCBs of various compositions, may contribute to the differences in bone maturation and formation..
7. Yuki Sugiura, Kunio Ishikawa, Kazuo Onuma, Yoji Makita, PO4 adsorption on the calcite surface modulates calcite formation and crystal size, American Mineralogist, 10.2138/am-2019-7015, 104, 10, 1381-1388, 2019.10, Calcium carbonate (CaCO3) and particularly its stable phase, calcite, is of great geological significance in the deep carbon cycle since CaCO3 from biomineralized shells and corals form sedimentary rocks. Calcite also attracts attention in medical science and pharmacy as a primary or intermediate component in biomaterials because it possesses excellent biocompatibility along with suitable physicochemical properties. Calcite blocks have already been used during surgical procedures as a bone substitute for reconstructing bone defects formed by diseases and injury. When producing CaCO3 biomaterials and bioceramics, in particular, in vivo control of the size and polymorphic nature of CaCO3 is required. In this study, we investigated the effects of PO4 on calcite formation during the phase conversion of calcium sulfate anhydrate (CaSO4, CSA), which is sometimes used as a starting material for bone substitutes because of its suitable setting ability. CSA powder was immersed in 2 mol/L Na2CO3 solution containing a range of PO4 concentrations (0-60 mmol/L) at 40 °C for 3 days. The treated samples were investigated by X-ray diffraction, Fourier-transform infrared spectroscopy, X-ray fluorescence spectroscopy, and thermal analysis. In addition, the fine structures of the treated samples were observed by field-emission scanning electron microscopy, and the specific surface area was measured. We found that PO4, which is universally present in vivo, can modulate the calcite crystal size during calcite formation. A fluorescence study and calcite crystal growth experiments indicated that PO4 adsorbs tightly onto the surface of calcite, inhibiting crystal growth. In the presence of high PO4 concentrations, vaterite is formed along with calcite, and the appearance and stability of the CaCO3 polymorphs can be controlled by adjusting the PO4 concentration. These findings have implications for medical science and pharmacology, along with mineralogy and geochemistry..
8. L. Valeikiene, R. Paitian, I. Grigoraviciute-Puroniene, K. Ishikawa, A. Kareiva, Transition metal substitution effects in sol-gel derived Mg3-xMx/Al1 (M = Mn, Co, Ni, Cu, Zn) layered double hydroxides, Materials Chemistry and Physics, 10.1016/j.matchemphys.2019.121863, 237, 2019.11, In the present study the transition metal substitution effects in Mg3-xMx/Al1 (M = Mn, Co, Ni, Cu, Zn) layered double hydroxides (LDHs) were investigated. For the synthesis of the mentioned compounds a newly developed sol-gel synthesis method has been applied. It was demonstrated that different amounts of Mn, Co, Ni, Cu and Zn could be introduced to the sol-gel derived LDHs without destroying the layered structure. The synthesis products were characterized using X-ray powder diffraction (XRD) analysis, infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The specific surface area of differently substituted Mg3-xMx/Al1 LDH specimens was also estimated. The synthesized LDHs could be tested for different medical applications and could be used as precursor material for the preparation of nanostructured mixed-metal oxides with a variety of useful properties..
9. Koichiro Hayashi, Ryo Kishida, Akira Tsuchiya, Kunio Ishikawa, Carbonate Apatite Micro-Honeycombed Blocks Generate Bone Marrow-Like Tissues as well as Bone, Advanced Biosystems, 10.1002/adbi.201900140, 3, 12, 2019.12, Hematopoietic stem cells form blood cells in bone marrow and reside in niches. Artificial environments that conserve these niches may generate bone marrow. Osteogenesis, angiogenesis, and material resorption must be regulated to create these environments. These processes are controlled by material composition and macro- and microporous structures. Here, three blocks with different micropore structures are fabricated. Carbonate apatite has nearly the same composition as natural human bone and their honeycomb structure facilitates cell penetration and survival. In samples with high microporosity, endosteum-like tissues such as sinusoids form in areas of material resorption and high local calcium concentration. These conditions resemble environments conducive to niche maintenance. Bone marrow–like tissues and megakaryocytes are successfully generated in this environment. Micropore structure is the most critical factor in bone marrow formation; however, the influences of material composition and macropore structure must also be considered. The results of this study may help develop treatments for bone marrow–related diseases and elucidate the components and functions of the hematopoietic stem cell niche..
10. Kunio Ishikawa, Edita Garskaite, Aivaras Kareiva, Sol–gel synthesis of calcium phosphate-based biomaterials—A review of environmentally benign, simple, and effective synthesis routes, Journal of Sol-Gel Science and Technology, 10.1007/s10971-020-05245-8, 2020.01, In this review article the available results about application of sol–gel synthesis method for the preparation of different calcium phosphates and composite materials are summarized. The attention is paid to calcium phosphate-containing compounds which show the biological properties and could be used as potential phosphate bioceramics in medicine. It was demonstrated that the sol–gel synthesis method is a powerful tool for the synthesis of calcium hydroxyapatite and other phosphates, and different calcium phosphate-based composites at mild synthetic conditions resulted in high reproducibility, high phase purity, and desired morphology. Thus, the sol–gel synthesis method enables the researchers to develop biomaterials with superior features in terms of biomedical applications..
11. Sunarso, Akira Tsuchiya, Riki Toita, Kanji Tsuru, Kunio Ishikawa, Enhanced osseointegration capability of poly(Ether ether ketone) via combined phosphate and calcium surface-functionalization, International journal of molecular sciences, 10.3390/ijms21010198, 21, 1, 2020.01, Biomedical applications of poly(ether ether ketone) (PEEK) are hindered by its inherent bioinertness and lack of osseointegration capability. In the present study, to enhance osteogenic activity and, hence, the osseointegration capability of PEEK, we proposed a strategy of combined phosphate and calcium surface-functionalization, in which ozone-gas treatment and wet chemistry were used for introduction of hydroxyl groups and modification of phosphate and/or calcium, respectively. Surface functionalization significantly elevated the surface hydrophilicity without changing the surface roughness or topography. The cell study demonstrated that immobilization of phosphate or calcium increased the osteogenesis of rat mesenchymal stem cells compared with bare PEEK, including cell proliferation, alkaline phosphatase activity, and bone-like nodule formation. Interestingly, further enhancement was observed for samples co-immobilized with phosphate and calcium. Furthermore, in the animal study, phosphate and calcium co-functionalized PEEK demonstrated significantly enhanced osseointegration, as revealed by a greater direct bone-to-implant contact ratio and bond strength between the bone and implant than unfunctionalized and phosphate-functionalized PEEK, which paves the way for the orthopedic and dental application of PEEK..
12. Naoyuki Fukuda, Kunio Ishikawa, Kazuya Akita, Kumiko Kamada, Naito Kurio, Yoshihide Mori, Youji Miyamoto, Effects of acidic calcium phosphate concentration on setting reaction and tissue response to β-tricalcium phosphate granular cement, Journal of Biomedical Materials Research - Part B Applied Biomaterials, 10.1002/jbm.b.34361, 108, 1, 22-29, 2020.01, Beta-tricalcium phosphate granular cement (β-TCP GC), consisting of β-TCP granules and an acidic calcium phosphate (Ca-P) solution, shows promise in the reconstruction of bone defects as it sets to form interconnected porous structures, that is, β-TCP granules are bridged with dicalcium phosphate dihydrate (DCPD) crystals. In this study, the effects of acidic Ca-P solution concentration (0–600 mmol/L) on the setting reaction and tissue response to β-TCP GC were investigated. The β-TCP GC set upon mixing with its liquid phase, based on the formation of DCPD crystals, which bridged β-TCP granules to one another. Diametral tensile strength of the set β-TCP GC was relatively the same, at ∼0.6 MPa, when the Ca-P concentration was 20–600 mmol/L. Due to the setting ability, reconstruction of the rat's calvarial bone defect using β-TCP GC with 20, 200, and 600 mmol/L Ca-P solution was much easier compared to that with β-TCP granules without setting ability. Four weeks after the reconstruction, the amount of new bone was the same, ∼17% in both β-TCP GC and β-TCP granules groups. Cellular response to β-TCP granules and β-TCP GC using the 20 mmol/L acidic Ca-P solution was almost the same. However, β-TCP GC using the 200 and 600 mmol/L acidic Ca-P solution showed a more severe inflammatory reaction. It is concluded, therefore, that β-TCP GC, using the 20 mmol/L acidic Ca-P solution, is recommended as this concentration allows surgical techniques to be performed easily and provides good mechanical strength, and the similar cellular response to β-TCP granules..
13. Olga Opuchovic, Mindaugas Andrulevicius, Sigitas Tamulevicius, Jean Luc Rehspringer, Aldona Beganskiene, Ramunas Skaudzius, Kunio Ishikawa, Aivaras Kareiva, Cerium doping and cerium aluminium co-doping effects on the sol-gel processing of Y3Fe5O12 (YIG)
Bulk and thin films, Solid State Sciences, 10.1016/j.solidstatesciences.2019.106065, 99, 2020.01, In the present study cerium substitution effects in the sol-gel derived yttrium iron garnet (Ce:Y3Fe5O12, Ce:YIG) have been investigated. To avoid formation of CeO2 as side phase the samples were prepared under different conditions. Synthesis of Ce:YIG in the reducing atmosphere, however, showed the formation of perovskite YFeO3 as dominant phase. Mixed-metal cerium substituted yttrium aluminium iron garnets (Ce:Y3Al5-xFexO12, Ce:YIAG) were synthesized in the form of bulk and coating. Single phase Y2.925Ce0.075Al5-xFexO12 (x = 1, 2, 3, and 4) were successfully synthesized using the same sol-gel processing route. The garnet thin films with composition of Y2.925Ce0.075Al1Fe4O12 were fabricated on a quartz substrate by dip-coating technique. The phase purity and structural features of obtained powders and thin films were evaluated using X-ray diffraction (XRD) analysis. The surface composition was determined by X-ray photoelectron spectroscopy (XPS). The morphology of synthesis products was investigated by scanning electron microscopy (SEM)..
14. Bang Le Thi, Rui Shi, Bui Duc Long, S. Ramesh, Shi Xingling, Yuki Sugiura, Kunio Ishikawa, Biological responses of MC3T3-E1 on calcium carbonate coatings fabricated by hydrothermal reaction on titanium, Biomedical Materials (Bristol), 10.1088/1748-605X/ab6939, 15, 3, 2020.01, Titainum (Ti) implants have been successfully used in orthopaedic and dental surgery. However, poor early bone tissue integration is still a common cause of implant failure. This could be modulated by improving the material bonding or adhesion directly to the bone by surface roughening and/or a bioresorbable and osteoconductive coating. In this study, we report on the biological behaviours of the Ti substrate with modified surface roughness and/or a calcium carbonate (CaCO3) coating. The roughened Ti surface was prepared using an acid etching reaction, and the CaCO3 coating on the substrates was synthesized by the hydrothermal treatment of Ti in calcium citrate complexes. This study demonstrates that surface roughening of Ti alone does not improve the biological response of the MC3T3-E1 cells, but a CaCO3 coating on the smooth Ti surface increases cell responses, and these effects are further enhanced by the combination of coating a roughened Ti surface with CaCO3. The larger the cell area, the greater the cell proliferation and increased bone-like nodule formation were observed on the CaCO3 coating of the roughened Ti surface. This observation was also supported by a higher ALP value. The cell behaviours found in the current study further support the development of CaCO3 coatings towards clinical application..
15. Thet Thet Swe, Khairul Anuar Shariff, Hasmaliza Mohamad, Kunio Ishikawa, Koichiro Hayashi, Mohamad Hafizi Abu Bakar, Behavioural response of cells and bacteria on single and multiple doped Sr and Ag S53P4 sol-gel bioglass, Ceramics International, 10.1016/j.ceramint.2020.04.094, 2020.01, The aim of this study is to investigate the response of cells and bacteria on Sr, Ag, and Sr + Ag doped S53P4 sol-gel bioglass. In this study, 3 mol% of SrO and 1 mol% of Ag2O were selected as doping for single and multiple doped S53P4 sol-gel bioglass. These doped specimens were denoted as BG, BG-3S, BG-1A, and BG-3S1A throughout the study. Cell study showed that the BG-3S1A specimen exhibited the highest proliferation of MC3T3-E1 osteoblast-like cells, ALP activity, and bone nodule formation in comparison with other specimens. Meanwhile, antibacterial study of the BG-3S1A specimen showed relatively similar antibacterial responses towards Escherichia coli and Staphylococcus aureus in comparison with the BG-1A specimen. Therefore, these findings proved that by combining appropriate amount of Sr and Ag doping ions into S53P4 bioglass composition, cellular proliferation and antibacterial response could be stimulated, which could benefit patients who suffer from bacteria-infected bone defect diseases..
16. Kunio Ishikawa, Aivaras Kareiva, Sol-gel synthesis of calcium phosphate-based coatings - A review, Chemija, 10.6001/chemija.v31i1.4169, 31, 1, 25-41, 2020.02, Calcium phosphate (CP)-based biomaterials, especially nanostructured ones, show a high biocompatibility and increased biological properties. The coatings composed of stoichiometric hydroxyapatite have been extensively used to improve integration of metallic implants in the host bone. However, these coatings exhibited several drawbacks that limited their successful application. It was concluded in numerous articles that the sol-gel derived coatings can undergo cracking and delamination and are scarcely uniform. In this review article the recent advances on the sol-gel synthesis of different phosphate coatings and thin films are summarized. The attention is paid to coatings and thin films of calcium hydroxyapatite (CHAp), other phosphates, bioglasses and different composite materials. The state of the art, limitations, potentialities, open challenges, and the future scenarios for the application of CP bioceramics are highlighted in this study..
17. Sunarso, Riki Toita, Kanji Tsuru, Kunio Ishikawa, Ozone-gas-mediated surface hydrophilization enhances the cell responses to titanium, Materials Letters, 10.1016/j.matlet.2019.127168, 261, 2020.02, Surface wettability is attracting increasing attention as an important factor that affects the cell/tissue responses of implant materials. Time-dependent hydrocarbon adsorption on the titanium (Ti) implant surface has been reported to decrease the surface hydrophilicity by adsorption of hydrocarbon contaminants from the atmosphere and dramatically decrease the osseointegration over time. In this study, we found that ozone-gas-mediated removal of hydrocarbon contaminants and introduction of –OH groups significantly increased the surface hydrophilicity of acid-etched Ti without changing the original surface topography. Ozone-gas-treated Ti dramatically enhanced osteogenic differentiation of mesenchymal stem cells, as evidenced by greater cell proliferation, alkaline phosphatase activity, and bone-like nodule formation compared with original Ti..
18. Inga Grigoraviciute-Puroniene, Zivile Stankeviciute, Kunio Ishikawa, Aivaras Kareiva, Formation of calcium hydroxyapatite with high concentration of homogeneously distributed silver, Microporous and Mesoporous Materials, 10.1016/j.micromeso.2019.109806, 293, 2020.02, In this study for the synthesis of silver-doped calcium hydroxyapatite (Ca10(PO4)6(OH)2:Ag; CHAp:Ag) an environmentally friendly aqueous sol-gel processing has been suggested. The sinterability and morphological properties of silver-activated calcium hydroxyapatite were investigated in the present study. The calcium hydroxyapatite doped with high concentration of silver (up to 10 wt %) has been prepared. This simple synthetic approach offers a feasible way to obtain highly homogeneous silver-doped CHAp bioceramics with possible application in medicine. The synthesis products were characterized using X-ray powder diffraction (XRD) analysis, infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The content of Ca, P and Ag in the synthesis products was determined by SEM (EDX)..
19. Rui Shi, Koichiro Hayashi, L. T. Bang, Kunio Ishikawa, Effects of surface roughening and calcite coating of titanium on cell growth and differentiation, Journal of Biomaterials Applications, 10.1177/0885328219883765, 34, 7, 917-927, 2020.02, Medical pure titanium (Ti) exhibits excellent mechanical properties and chemical stability in clinical use, but its initial osteointegration period is often postponed due to the bioinert nature of the Ti surface. Roughening and bioactive material coating of Ti implant surfaces are considered effective to enhance the bioactivity of Ti implants. In this study, we evaluated the effects of surface roughening and calcite (CaCO3) coating of Ti substrates on osteoblastic cell differentiation and growth. We roughened the Ti substrate surface by acid etching, followed by coating with calcite by thermal decomposition of Ca(NO3)2 to CaO followed by thermal carbonation of CaO to CaCO3. The surface topography of roughened Ti substrates (rough Ti) fluctuated, and the arithmetic average of surface roughness (Ra) was 2.2 µm. The rough topography was retained even after calcite coating of rough Ti, and the calcite-coated Ti (calcite-Ti) has an Ra of 2.0 µm. The tensile adhesive and shear adhesive strengths between calcite coating and Ti surface in calcite–Ti were 56.6 ± 16.1 and 10.1 ± 1.39 MPa, respectively. The biological properties and response of calcite–Ti were evaluated in vitro using a pre-osteoblastic cell line (MC3T3-E1). Observation of cell morphology by scanning electron microscopy and immunofluorescence staining revealed that MC3T3-E1 cells attached favorably to the surface with polygonal and filopodial extensions on calcite–Ti. The combination of roughening and calcite coating of the Ti substrate surface significantly increased cell proliferation at 1, 3, and 7 days of incubation. Furthermore, the relative alkaline phosphatase activity of calcite–Ti was higher than that of untreated Ti substrates (smooth Ti) and rough Ti after incubation for 7 days. Thus, the combined surface roughening and calcite coating of Ti substrates promoted MC3T3-E1 differentiation, whereas roughening alone was not effective..
20. Koichiro Hayashi, Ryo Kishida, Akira Tsuchiya, Kunio Ishikawa, Granular Honeycombs Composed of Carbonate Apatite, Hydroxyapatite, and β-Tricalcium Phosphate as Bone Graft Substitutes
Effects of Composition on Bone Formation and Maturation, ACS Applied Bio Materials, 10.1021/acsabm.0c00060, 3, 3, 1787-1795, 2020.03, Material composition and porous structure are important factors in the formation and maturation of newly formed bone and replacement of materials by new bone. Conventional bone graft materials often lack suitability for bone generation because of the complexity of their macroporous structures, which can interfere with the penetration of cells related to bone remodeling and angiogenesis in the materials. In the present study, carbonate apatite (CO3Ap), hydroxyapatite (HAp), and β-tricalcium phosphate (TCP) honeycomb granules (HCGs) with uniformly sized macropores (∼115 μm) were fabricated. These HCG macropores were arranged in a regular fashion and penetrated straight into the granules. They were implanted into a rabbit femur defect for further evaluation. In the CO3Ap HCG implantation group, mature bone formed within CO3Ap HCG macropores by 4 weeks after grafting, and a large portion of CO3Ap HCGs was replaced by new bone at 12 weeks. By contrast, in the β-TCP HCG implantation group, new bone was not always formed in the regions after β-TCP HCG disappearance, and immature bone was present within β-TCP HCG macropores even after 12 weeks. HAp HCGs were not resorbed, and their macropores were filled with immature bone. The area of mature bone in the CO3Ap HCG implantation group was 3.3 and 1.6 times higher at 4 weeks and 2.2 and 1.7 times higher at 12 weeks compared with the HAp and β-TCP HCG implantation groups, respectively. Furthermore, the degrees of bone maturation for CO3Ap, HAp, and β-TCP HCGs were 100, 34, and 64% at 4 weeks, and 100, 54, and 69% at 12 weeks, respectively. Thus, the composition of the HCGs affected bone formation and maturation..
21. Kazuya Akita, Naoyuki Fukuda, Kumiko Kamada, Keiko Kudoh, Naito Kurio, Kanji Tsuru, Kunio Ishikawa, Youji Miyamoto, Fabrication of porous carbonate apatite granules using microfiber and its histological evaluations in rabbit calvarial bone defects, Journal of Biomedical Materials Research - Part A, 10.1002/jbm.a.36850, 108, 3, 709-721, 2020.03, Carbonate apatite (CO3Ap) granules are known to show good osteoconductivity and replaced to new bone. On the other hand, it is well known that a porous structure allows bone tissue to penetrate its pores, and the optimal pore size for bone ingrowth is dependent on the composition and structure of the scaffold material. Therefore, the aim of this study was to fabricate various porous CO3Ap granules through a two-step dissolution–precipitation reaction using CaSO4 as a precursor and 30-, 50-, 120-, and 205-μm diameter microfibers as porogen and to find the optimal pore size of CO3Ap. Porous CO3Ap granules were successfully fabricated with pore size 8.2–18.7% smaller than the size of the original fiber porogen. Two weeks after the reconstruction of rabbit calvarial bone defects using porous CO3Ap granules, the largest amount of mature bone was seen to be formed inside the pores of CO3Ap (120) [porous CO3Ap granules made using 120-μm microfiber] followed by CO3Ap (50) and CO3Ap (30). At 4 and 8 weeks, no statistically significant difference was observed based on the pore size, even though largest amount of mature bone was formed in case of CO3Ap (120). It is concluded, therefore, that the optimal pore size of the CO3Ap is that of CO3Ap (120), which is 85 μm..
22. T. T. Swe, H. Mohamad, K. A. Shariff, A. F.M. Noor, K. Ishikawa, A. A. Thant, Synthesis and Characterization of Bioactive Quaternary Silicate Gel-glasses, Regional Conference on Materials and ASEAN Microscopy Conference 2017, RCM and AMC 2017 Journal of Physics: Conference Series, 10.1088/1742-6596/1082/1/012070, 1082, 1, 2018.10, Bioactive glasses and glass-ceramics were applied in bone fix applications, dental applications as well as in tissue engineering. In the current study, a new quaternary silicate bioglass S50P4 (50%SiO2-24.5%Na2O-21.5%CaO-4%P2O5) with different aging time (3, 5 and 7 days) was prepared by sol-gel method. These synthesized glasses were analyzed using X-ray powder diffraction (XRD), Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Whereas the bioactivity of the optimized samples were observed through in-vitro test using Hank's Balanced Salt Solution (HBSS) at different soaking time (7 and 14 days). XRD results indicate that the crystalline patterns in gel-derived glass aged for 3 days exhibit stronger peaks compare to samples aged for 5 and 7 days. This could be attributed to the difference of water content inside the gels. Moreover, the peak at 2θ∼33° became sharper and more intense for longer soaking times corresponds to the apatite structure. Besides, in-vitro test shows, the formation of hydroxyl carbonated apatite layer (HCA) with finer grains..
23. Khairul Anuar Shariff, Kanji Tsuru, Kunio Ishikawa, Micro-CT evaluation on osteoconductivity of DCPD-coated β-TCP granule using experimental rats, Regional Conference on Materials and ASEAN Microscopy Conference 2017, RCM and AMC 2017 Journal of Physics: Conference Series, 10.1088/1742-6596/1082/1/012069, 1082, 1, 2018.10, β-tricalcium phosphate (β-TCP) bone substitutes have been widely used because of its excellent tissue response and good osteoconductivity. However, recent study reported that the osteoconductivity of β-TCP could be enhanced by treating β-TCP surfaces with saturated acidic calcium phosphate solution. In this study, the osteoconductivity of treated β-TCP granule were evaluated using micro-computed tomography (micro-CT) scan technique. The granule specimens were obtained by exposing β-TCP granules with saturated acidic calcium phosphate solution for 10, 30 and 60 mins, respectively. Then, critical bone defect size with dimension of 9 mm were made at rat calvarial, and the defect was reconstructed with 10, 30 and 60 mins treated β-TCP granules and β-TCP granules without treatment as a control. After 2 and 4 weeks implantation, the specimens with the surrounding bone tissue were taken out and examined using micro-CT machine. Based on the cross section of micro-CT images, new bone formations were observed from the edge of the defect towards the center of the bone defect area in all specimens. At 2 weeks, new bone formations were observed for 10 min and 30 min treated β-TCP granules when compared with other specimens. The 30 min treated β-TCP granules showed faster new bone formation rate after 4 weeks implantation. It can be concluded that 30 min treated β-TCP granules revealed the highest osteoconductivity in comparison to the other specimens..
24. Akira Tsuchiya, Marino Sato, Ichiro Takahashi, Kunio Ishikawa, Fabrication of apatite-coated gypsum granules and histological evaluation using rabbits, Ceramics International, 10.1016/j.ceramint.2018.08.021, 44, 16, 20330-20336, 2018.11, Calcium sulfate dihydrate (CSD) has been used as a material for bone augmentation for many years. However, rapid resorption of CSD sometimes results in insufficient formation of new bone. In the present study, the feasibility of fabricating apatite-coated CSD (Ap/CSD) was studied, with the hypothesis that the apatite coating would reduce the rate of CSD resorption and enhance the osteoconductivity. To prepare Ap/CSD granules, 300–400 µm CSD granules were immersed in Na2HPO4 solution at 20 °C or 60 °C, resulting in granules coated with apatitic precipitates. Granules were analyzed by microscopy and x-ray diffraction, and the dissolution rate into pH 7.5 Tris-HCl buffer solution was measured. Osteoconductivity was assessed by the release of calcium ions, and their ability to stimulate new bone formation was examined through reconstruction of rabbit distal femur bone defects. It was found that the apatite coating resulted in increased osteoconduction and a decreased dissolution rate compared with bare CSD granules. When rabbit distal femur bone defect was reconstructed with Ap/CSD, CSD and sintered hydroxyapatite (s-HAp), all samples demonstrated an excellent tissue response. Four weeks after surgery, a higher radio opacity was obtained for Ap/CSD when compared with CSD, indicating new bone formation. The s-HAp granules remained and thus, new bone formation was smallest even though s-HAp granules bonded with the bone. Ap/CSD that was fabricated at 60 °C induced greater bone formation than CSD. It is therefore concluded that Ap/CSD has good potential value as a bone augmentation material..
25. Arief Cahyanto, Kanji Tsuru, Kunio Ishikawa, Effect of setting atmosphere on apatite cement resorption
An in vitro and in vivo study, Journal of the Mechanical Behavior of Biomedical Materials, 10.1016/j.jmbbm.2018.08.021, 88, 463-469, 2018.12, Objectives: The aim of this present study was to investigate the effect of setting atmosphere on replacement of apatite cement with new bone both in vitro and in vivo. Material and methods: Apatite cement consisting of an equimolar mixture of tetracalcium phosphate and anhydrous dicalcium phosphate was mixed with distilled water and allowed to set at 37 °C and 100% relative humidity under 0%, 5%, and 100% CO2 atmospheres. X-Ray diffraction and Fourier Transform Infrared Spectroscopy were employed to confirm the carbonate apatite formation. Micro-CT and histological evaluation was made at 1 and 6 month(s) using twelve 10-week-old specific-pathogen-free male Wistar rats. Results: B-type carbonate apatite was found when the apatite cement was set under 100% CO2 and 5% CO2. More carbonate apatite was formed in the case of 100% CO2 when compared with 5% CO2, and none was formed under 0% CO2. Interestingly, unreacted tetracalcium phosphate was significant when apatite cement was set under 0% CO2, indicating the formation of Ca-deficient hydroxyapatite. When a bone defect of rat tibia was reconstructed in these conditions of apatite cement and sintered hydroxyapatite, replacement of the apatite cement was confirmed 6 months after implantation, whereas no replacement was observed in the case of sintered hydroxyapatite. The amount of replacement of apatite cement with bone was greater, on the order of 100% CO2 and 5% CO2, followed by 0% CO2. Conclusion: The results obtained in the present study demonstrated that setting atmosphere clearly plays an important role in the replacement of set apatite cement with bone..
26. Kunio Ishikawa, Koichiro Hayashi, Akira Tsuchiya, Ryo Kishida, Vertical bone augmentation using carbonate apatite bone substitute, 42nd Society for Biomaterials Annual Meeting and Exposition 2019: The Pinnacle of Biomaterials Innovation and Excellence Society for Biomaterials Annual Meeting and Exposition 2019 The Pinnacle of Biomaterials Innovation and Excellence - Transactions of the 42nd Annual Meeting, 2019.01, Statement of Purpose: Recently, AB-type carbonate apatite (CO3Ap) bone substitute block was fabricated by just immersing a precursor, CaCO3 block, in sodium phosphate solution through dissolution-precipitation reaction. CO3Ap block showed higher osteoconductivity and replaced to bone. It should be noted that not only composition but also structure plays important role for the replacement to bone since porous structure allows cells penetration interior to the bone substitute. One of the interesting porous structures is honeycomb. In this study, CO3Ap honeycomb was fabricated, and evaluated its usefulness as vertical bone augmentation device using rabbits as experimental animals..
27. Naoyuki Fukuda, Akira Tsuchiya, Sunarso, Riki Toita, Kanji Tsuru, Yoshihide Mori, Kunio Ishikawa, Surface plasma treatment and phosphorylation enhance the biological performance of poly(ether ether ketone), Colloids and Surfaces B: Biointerfaces, 10.1016/j.colsurfb.2018.09.032, 173, 36-42, 2019.01, Poly(ether ether ketone) (PEEK) has emerged as an alternative endosseous material to metal implants mainly because of its lack of allergic sensitivity and radiolucency, while maintaining similar mechanical properties with bone. However, a disadvantage of PEEK is its weak osseointegration ability compared with metal implants. To overcome this, we prepared a phosphate group-modified PEEK by plasma treatment and subsequent phosphorylation reaction. Plasma treatment and phosphate modification of PEEK changed its hydrophobic surface to a hydrophilic surface while maintaining the original surface topography and roughness. Phosphate modification increased the bioactivity of rat bone marrow stromal cells (BMSCs), including proliferation, alkaline phosphatase activity, and bone-like nodule formation; however, this effect was negligible in plasma-treated PEEK. In addition, phosphate modification attenuated the phenotypic polarization of lipopolysaccharide-primed RAW264.7 macrophages to an inflammatory phenotype, based on the finding that macrophages on phosphate-modified PEEK produced decreased levels of the inflammatory cytokine and increased levels of the anti-inflammatory cytokine. Finally, in an animal study, phosphate-modified PEEK exhibited a doubled pullout force from the femur bone cavity compared with bare PEEK. Thus, we conclude that phosphate modification can significantly improves the implant-bone bonding strength of PEEK by enhancing BMSCs activity and reducing excessive inflammation..
28. Yukari Ihara, Toru Takeshita, Shinya Kageyama, Rie Matsumi, Mikari Asakawa, Yukie Shibata, Yuki Sugiura, Kunio Ishikawa, Ichiro Takahashi, Yoshihisa Yamashita, Identification of initial colonizing bacteria in dental plaques from young adults using full-length 16S rRNA gene sequencing, mSystems, 10.1128/mSystems.00360-19, 4, 5, 2019.01, Development of dental plaque begins with the adhesion of salivary bacteria to the acquired pellicle covering the tooth surface. In this study, we collected in vivo dental plaque formed on hydroxyapatite disks for 6 h from 74 young adults and identified initial colonizing taxa based on full-length 16S rRNA gene sequences. A long-read, single-molecule sequencer, PacBio Sequel, provided 100,109 high-quality full-length 16S rRNA gene sequence reads from the early plaque microbiota, which were assigned to 90 oral bacterial taxa. The microbiota obtained from every individual mostly comprised the 21 predominant taxa with the maximum relative abundance of over 10% (95.8 6.2%, mean SD), which included Streptococcus species as well as nonstreptococcal species. A hierarchical cluster analysis of their relative abundance distribution suggested three major patterns of microbiota compositions: a Streptococcus mitis/Streptococcus sp. HMT-423-dominant profile, a Neisseria sicca/Neisseria flava/Neisseria mucosadominant profile, and a complex profile with high diversity. No notable variations in the community structures were associated with the dental caries status, although the total bacterial amounts were larger in the subjects with a high number of caries-experienced teeth (8) than in those with no or a low number of caries-experienced teeth. Our results revealed the bacterial taxa primarily involved in early plaque formation on hydroxyapatite disks in young adults. IMPORTANCE Selective attachment of salivary bacteria to the tooth surface is an initial and repetitive phase in dental plaque development. We employed full-length 16S rRNA gene sequence analysis with a high taxonomic resolution using a third-generation sequencer, PacBio Sequel, to determine the bacterial composition during early plaque formation in 74 young adults accurately and in detail. The results revealed 21 bacterial taxa primarily involved in early plaque formation on hydroxyapatite disks in young adults, which include several streptococcal species as well as nonstreptococcal species, such as Neisseria sicca/N. flava/N. mucosa and Rothia dentocariosa. Given that no notable variations in the microbiota composition were associated with the dental caries status, the maturation process, rather than the specific bacterial species that are the initial colonizers, is likely to play an important role in the development of dysbiotic microbiota associated with dental caries..
29. T. T. Swe, K. A. Shariff, A. F.M. Noor, K. Ishikawa, H. Mohamad, Effect of silver on the apatite formation of bioactive silicate glass, 6th International Conference on Recent Advances in Materials, Minerals and Environment, RAMM 2018 Materials Today: Proceedings, 10.1016/j.matpr.2019.06.385, 17, 884-888, 2019.01, Silver (Ag) has the antibacterial property and can be easily introduced in glasses and glass-ceramics. In this research, the effect of Ag addition on the apatite formation of sol-gel derived new composition bioactive glass (BG) (55%SiO2 - 4% P2O5 -22%Na2O - (19-x) %CaO -x% Ag2O) (x=0, 5 and 8%) were investigated. The synthesized Ag doped BG samples were treated in Hank's Balanced Salt Solution (HBSS) for 14 days to study the bioactivity. The achieved samples were evaluated by X-ray powder diffraction (XRD) and Scanning electron microscope (SEM). The XRD spectra clearly show diffraction peaks of bone-like hydroxyapatite (HAp) for all samples after immersion in HBSS. However, the more intense of HAp peak at 32° was detected in Ag(5%) and Ag(8%) BGs compared with undoped BG. All glass samples are bioactive but BG with 8 wt% of Ag2O exhibited more apatite than the samples containing 5 wt% of Ag2O, as seen in SEM images. After 14 days immersion, full coverage of apatite in cluster crystal form on the Ag(8) glass surface was observed..
30. Thet Thet Swe, Khairul Anuar Shariff, Ahmad Fauzi Mohd Noor, Kunio Ishikawa, Hasmaliza Mohamad, Effect of aging time on the crystal structure of new quaternary silicate gel-glasses, 2017 Conference on Biomedical and Advanced Materials, Bio-CAM 2017 Materials Today: Proceedings, 10.1016/j.matpr.2019.06.033, 16, 1668-1672, 2019.01, Bioactive glasses and glass-ceramics were applied in bone fix applications, dental applications as well as in tissue engineering. New S50P4 glass with a composition of SiO2-Na2O-CaO-P2O5 in the quaternary system with different aging time (3, 5 and 7 days) was prepared by sol-gel method. XRD results indicate that the crystalline patterns in gel-derived glass aged for 3 days exhibit high intensity peaks compare to samples aged for 5 and 7 days. In FTIR spectra, the intensity of the crystalline silicate and phosphate phases were decreased with an increase aging time..
31. Kunio Ishikawa, Carbonate apatite bone replacement
Learn from the bone, Journal of the Ceramic Society of Japan, 10.2109/jcersj2.19042, 127, 9, 595-601, 2019.01, Bone is not composed of hydroxyapatite (HAp), but of carbonate apatite (CO3Ap). Although the decomposition of CO3Ap begins at around 400°C, and thus, the fabrication of CO3Ap blocks by sintering is difficult, CO3Ap blocks have recently been fabricated via a dissolutionprecipitation reaction in Na2HPO4 solution using a CaCO3 block as a precursor. Compared to sintered HAp, which is not resorbed by osteoclasts, CO3Ap is resorbed by osteoclasts. Furthermore, CO3Ap upregulates the differentiation of osteoblasts. Therefore, CO3Ap can be used as a replacement for bones with regards to the so-called bone remodeling process. Clinical trials have confirmed the safety and usefulness of CO3Ap granules, including the replacement of CO3Ap granules to new bone. In Dec 2017, CO3Ap was approved as an artificial bone substitute by the Pharmaceuticals and Medical Devices Agency. CO3Ap granules can be used for all dental and maxillofacial surgeries, including the bone reconstruction aimed for dental implantation..
32. Ira Artilia, Kanji Tsuru, Kunio Ishikawa, Biocompatibility of hydrophilicity improved apatite cement, Journal of Biomimetics, Biomaterials and Biomedical Engineering, 10.4028/www.scientific.net/JBBBE.43.124, 43, 124-129, 2019.01, Hydrophilicity of apatite cement was increased after O3 gas treatment on apatite cement (AC) powder. It results on the improvement of the handling and mechanical properties of set AC. Behavior of osteoblastic cells to O3-treated set AC was evaluated including initial cell attachment, morphology of the attached cells and proliferation using rat bone marrow cell (RBM). Cells’ response to the set AC was the same regardless of O3 treatment. The cells well attached and spread with filopodial extensions even over the O3-treated set AC specimens. The rates of cell proliferation on set AC were also the same regardless of O3 treatment. The result indicated O3 treatment of AC powder would not affect to the osteoblast cell response of set AC..
33. Tansza S. Putri, Koichiro Hayashi, Kunio Ishikawa, Fabrication of three-dimensional interconnected porous blocks composed of robust carbonate apatite frameworks., Ceramics International, https://doi.org/10.1016/j.ceramint.2020.05.076, 46, 12, 20045-20049, 2020.08.
34. Lauryna Sinusaite, Anton Popov, Andris Antuzevics, Kestutis Mazeika, Dalis Baltrunas, Jen Chang Yang, Jiun Lin Horng, Shengfang Shi, Tohru Sekino, Kunio Ishikawa, Aivaras Kareiva, Aleksej Zarkov, Fe and Zn co-substituted beta-tricalcium phosphate (β-TCP): Synthesis, structural, magnetic, mechanical and biological properties., Materials Science & Engineering C, https://doi.org/10.1016/j.msec.2020.110918, 112, 110918-110918, 2020.07.
35. Koichiro Hayashi, Melvin L. Munar, Kunio Ishikawa, Effects of macropore size in carbonate apatite honeycomb scaffolds on bone regeneration., Materials Science & Engineering C, https://doi.org/10.1016/j.msec.2020.110848, 111, 2020.06.
36. Stasys Tautkus, Kunio Ishikawa, Rimantas Ramanauskas, Aivaras Kareiva, Zinc and chromium co-doped calcium hydroxyapatite: Sol-gel synthesis, characterization, behaviour in simulated body fluid and phase transformations., Journal of Solid State Chemistry, https://doi.org/10.1016/j.jssc.2020.121202, 284, 2020.04.
37. Yuta Sakemi, Koichiro Hayashi, Akira Tsuchiya, Yasuharu Nakashima, Kunio Ishikawa, Fabrication and histological evaluation of porous carbonate apatite block from gypsum block containing spherical phenol resin as a porogen. , Materials, 10.3390/ma12233997, 12, 23, 2019.12.
38. Tansza Setiana Putri, Koichiro Hayashi, Kunio Ishikawa, Bone regeneration using β-tricalcium phosphate (β-TCP) block with interconnected pores made by setting reaction of β-TCP granules., Journal of Biomedical Materials Research: Part A, 10.1002/jbm.a.36842, 2019.11.
39. Takamitsu Mano, Kazuya Akita, Naoyuki Fukuda, Kumiko Kamada, Naito Kurio, Kunio Ishikawa, Youji Miyamoto, Histological comparison of three apatitic bone substitutes with different carbonate contents in alveolar bone defects in a beagle mandible with simultaneous implant installation., Journal of Biomedical Materials Research: Part B - Applied Biomaterials, 10.1002/jbm.b.34492, 2019.10.
40. Takayuki Nakagawa, Naoyuki Fukuda, Shohei Kasugai, Noriko Tachikawa, Kiyoshi Koyano, Yasuyuki Matsushita, Masanori Sasaki, Kunio Ishikawa, Youji Miyamoto, Application of low crystalline carbonate apatite granules in two-stage sinus floor augmentation: a prospective clinical trial and histomorphometric evaluation. , Journal of Periodontal & Implant Science, 10.5051/jpis.2019.49.6.382, 49, 6, 382-396, 2019.12.
41. Yuki Sugiura, Kunio Ishikawa, Effect of Ca and PO4 on compositional conversion from dicalcium hydrogen phosphate dihydrate blocks to octacalcium phosphate blocks., Crystals, https://doi.org/10.3390/cryst8050222, 8, 5, 222-222, 2018.05.
42. Garima Tripathi, Kunio Ishikawa, Fabrication and in vitro dissolution evaluation of low-crystalline β-TCP blocks through aqueous solution mediated phase conversion. , Materials Science & Engineering C, 10.1016/j.msec.2019.03.106, 101, 228-231, 2019.08.
43. Lauryna Sinusaite, Inga Grigoraviciute-Puroniene, Anton Popov, Kunio Ishikawa, Aivaras Kareiva, Aleksej Zarkov, Controllable synthesis of tricalcium phosphate (TCP) polymorphs by wet precipitation: Effect of washing procedure., Ceramics International, 10.1016/j.ceramint.2019.03.174, 45, 9, 12423-12428, 2019.06.
44. Keiko Kudoh, Naoyuki Fukuda, Shohei Kasugai, Noriko Tachikawa, Kiyoshi Koyano, Yasuyuki Matsushita, Yoichiro Ogino, Kunio Ishikawa, Youji Miyamoto, Maxillary sinus floor augmentation using low-crystalline carbonate apatite granules with simultaneous implant installation: First-in-human clinical trial., Journal of Oral and Maxillofacial Surgery, 10.1016/j.joms.2018.11.026, 77, 5, 985-e1-985.e11, 2019.05.
45. Yuki Sugiura, Kunio Ishikawa, Fabrication of pure octacalcium phosphate blocks from dicalcium hydrogen phosphate dihydrate blocks via a dissolution-precipitation reaction in a basic solution., Materials Letters, 10.1016/j.matlet.2018.12.093, 293, 143-146, 2018.12.
46. Kunio Ishikawa, Tya Indah Arifta, Koichiro Hayashi, Kanji Tsuru, Fabrication and evaluation of interconnected porous carbonate apatite from alpha tricalcium phosphate spheres., Journal of Biomedical Materials Research: Part B - Applied Biomaterials., 10.1002/jbm.b.34117, 107, 2, 269-277, 2019.02.
47. Naoyuki Fukuda, Masayuki Kanazawa, Kanji Tsuru, Akira Tsuchiya, Sunarso, Riki Toita, Yoshihide Mori, Yasuharu Nakashima, Kunio Ishikawa, Synergistic effect of surface phosphorylation and micro-roughness on enhanced osseointegration ability of poly(ether ether ketone) in the rabbit tibia., Scientific Reports, 10.1038/s41598-018-35313-7, 8, 1, 16887, 2018.12.
48. Kunio Ishikawa, Youji Miyamoto, Akira Tsuchiya, Koichiro Hayashi, Kanji Tsuru, Go Ohe, Physical and histological comparison of hydroxyapatite, carbonate apatite, and β-tricalcium phosphate bone substitutes., Materials, 10.3390/ma11101993, 11, 10, 1993, 2018.10.
49. Eddy, Akira Tsuchiya, Kanji Tsuru, Kunio Ishikawa, Fabrication of self-setting β-TCP granular cement using β-TCP granules and sodium hydrogen sulfate solution., Journal of Biomaterials Applications, 10.1177/0885328218808015, 33, 5, 630-636, 2018.10.
50. Rui Shi, Yuki Sugiura, Kanji Tsuru, Kunio Ishikawa, Fabrication of calcite-coated rough-surface titanium using calcium nitrate., Surface and Coatings Technology, 10.1016/j.surfcoat.2018.09.050, 356, 72-79, 2018.12.
51. Yuki Sugiura, Melvin L Munar, Kunio Ishikawa, Fabrication of octacalcium phosphate block through a dissolution-precipitation reaction using a calcium sulphate hemihydrate block as a precursor., Journal of Materials Science: Materials in Medicine, 10.1007/s10856-018-6162-1, 29, 10, 151-158, 2018.09.
52. Yuki Sugiura, Kunio Ishikawa, Fabrication of carbonate apatite blocks from octacalcium phosphate blocks through different phase conversion mode depending on carbonate concentration., Journal of Solid State Chemistry, 10.1016/j.jssc.2018.08.008, 267, 85-91, 2018.11.
53. Masako Fujioka-Kobayashia, Kanji Tsuru, Hirokazu Nagai, Kenji Fujisawa, Takaharu Kudou, Go Ohe, Kunio Ishikawa, Youji Miyamoto, Fabrication and evaluation of carbonate apatite-coated calcium carbonate bone substitutes for bone tissue engineering. , Journal of Tissue Engineering and Regenerative Medicine, 10.1002/term.2742, 12, 10, 2077-2087, 2018.07.
54. Garima Tripath, Yuki Sugiura, Kanji Tsuru, Kunio Ishikawa, In Vivo stability evaluation of Mg substituted low crystallinity β-tricalcium phosphate blocks fabricated through dissolution–precipitation reaction for fast bone regeneration. , Biomedical Materials, 10.1088/1748-605X/aad385, 13, 6, 065002, 2018.08.
55. Garima Tripath, Yuki Sugiura, Aivaras Kareiva, Edita Garskaite, Kanji Tsuru, Kunio Ishikawa, Feasibility evaluation of low-crystallinity β-tricalcium phosphate blocks as a bone substitute fabricated by a dissolution–precipitation reaction from α-tricalcium phosphate blocks., Journal of Biomaterials Applications, 10.1177/0885328218788255, 33, 2, 259-270, 2018.08, Although sintered β-tricalcium phosphate blocks have been used clinically as artificial bone substitutes, the crystallinity of β-tricalcium phosphate, which might dominate biocompatibility, is extremely high. The objective of this study is to evaluate the feasibility of fabricating low-crystallinity β-tricalcium phosphate blocks, which are expected to exhibit good biocompatibility via a dissolution-precipitation reaction of α-tricalcium phosphate blocks as a precursor under hydrothermal conditions at 200°C for 24 h. Although β-tricalcium phosphate is a metastable phase, the presence of Mg2+ in the reaction solution inhibits the formation of its corresponding stable phase and induces β-tricalcium phosphate formation under acidic conditions. It was found that low-crystallinity β-tricalcium phosphate blocks could be fabricated from α-tricalcium phosphate blocks immersed in 1.0 mol/L MgCl2 + 0.1 mol/L NaH2PO4 solution while maintaining the shape of the α-tricalcium phosphate blocks. The crystallite size of the fabricated β-tricalcium phosphate blocks was 42 nm, which was substantially smaller than that of the sintered β-tricalcium phosphate blocks. When the fabricated β-tricalcium phosphate blocks were implanted into bone defects in rabbit femurs, they exhibited excellent tissue responses. In particular, the initial osteoconductivity (two and four weeks) was substantially greater than that of sintered β-tricalcium phosphate blocks..
56. Kenji Fujisawa, Kazuya Akita, Naoyuki Fukuda, Go Ohe, Kanji Tsuru, Kunio Ishikawa, Youji Miyamoto, Compositional and histological comparison of carbonate apatite fabricated by dissolution-precipitation reaction and Bio-Oss®., Journal of Materials Science: Materials in Medicine, 10.1007/s10856-018-6129-2, 29, 121-121, 2018.08, Carbonate apatite (CO3Ap) is an inorganic component of bone. This study aimed to compare the composition and tissue response to of CO3Ap (CO3Ap-DP) fabricated by the dissolution–precipitation reaction using calcite as a precursor and Bio-Oss®, which is widely used in orthopedic and dental fields as a synthetic bone substitute. X-ray diffraction and Fourier transform infrared results showed that CO3Ap-DP and Bio-Oss® were both B-type carbonate apatite with low crystallinity. The average sizes of CO3Ap-DP and Bio-Oss® granules were 450 ± 58 and 667 ± 168μ m, respectively, and their carbonate contents were 12.1 ± 0.6 and 5.6 ± 0.1 wt%, respectively. CO3Ap-DP had a larger amount of CO3 than Bio-Oss® but higher crystallinity than Bio-Oss®. When a bone defect made at the femur of rabbits was reconstructed with CO3Ap-DP and Bio-Oss®, CO3Ap-DP granules were partially replaced with bone, whereas Bio-Oss® remained at 8 weeks after implantation. CO3Ap-DP granules elicited a significantly larger amount of new bone formation at the cortical bone portion than Bio-Oss® at 4 weeks after the implantation. The results obtained in the present study demonstrated that CO3Ap-DP and Bio-Oss® showed different behavior even though they were both classified as CO3Ap. The CO3 content in CO3Ap played a more important role than the crystallinity of CO3Ap for replacement to bone and high osteoconductivity..
57. Yuki Sugiura, Kunio Ishikawa, Effect of calcium and phosphate on compositional conversion from dicalcium hydrogen phosphate dihydrate blocks to octacalcium phosphate blocks, Crystals, 10.3390/cryst8050222, 8, 5, 2018.05, Octacalcium phosphate (OCP) has attracted much attention as an artificial bone substitute because of its excellent osteoconductive and bone replacement properties. Although numerous studies have investigated OCP powder fabrication, there are only a few studies on OCP block fabrication. Therefore, in this study, the feasibility of optimizing dicalcium hydrogen phosphate dihydrate (DCPD) blocks, as a precursor for OCP block fabrication, under a pH 6 adjusted acetate buffer solution at 70 C for 2 days was investigated. When a DCPD block was immersed in acetate buffer, the block was partially converted to OCP, with a large amount of dicalcium hydrogen phosphate anhydrate (DCPA), and its macroscopic structure was maintained. When the DCPD block was immersed in a Ca-containing solution, it was converted to mainly hydroxyapatite (HAp) with DCPA. On the other hand, when the DCPD block was immersed in a PO4-containing solution, the block was converted to OCP, and its macroscopic structure was maintained. In other words, the PO4-induced calcium phosphate with a Ca/P molar ratio lower than 1.0 may represent an intermediate phase during the compositional transformation from a DCPD block to an OCP block through the dissolution–precipitation reaction..
58. Sunarso, Akira Tsuchiya, Naoyuki Fukuda, Riki Toita, Kanji Tsuru, Kunio Ishikawa, Effect of micro-roughening of poly(ether ether ketone) on bone marrow derived stem cell and macrophage responses, and osseointegration, Journal of Biomaterials Science, Polymer Edition, 10.1080/09205063.2018.1461448, 1-14, 2018.04, Poly(ether ether ketone) (PEEK) has emerged as a candidate to replace metal implants because of its satisfactory mechanical properties, radiolucency, and lack of metal allergy. However, PEEK lacks osseointegration ability limiting its clinical applications. To overcome this problem, we prepared PEEK with a micro-rough surface using the sandblast method to modulate its osseointegration property; the sandblast method is simple, cost-effective, and is already applied to clinical metal implants. The surface roughness of the sandblasted PEEK was about 2.3 μm, whereas that of mirror-polished PEEK was 0.06 μm. Rat bone marrow-derived mesenchymal stem cells (RMSCs) showed higher proliferation, osteocalcin (OC) expression and bone-like nodule formation on micro-roughened PEEK compared with those cultured on mirror-polished PEEK, suggesting that micro-roughening facilitated RMSCs proliferation and differentiation. The micro-roughened surface slightly mitigated secretion of inflammatory C-C motif chemokine 2 (CCL-2) from lipopolysaccharide (LPS)-stimulated macrophages, but not of tumor necrosis factor α (TNFα) and interleukin-6 (IL-6). Finally, to compare osseointegration, specimens were implanted in rat femur bone marrow cavities, and then the pull-out force was measured. The pull-out force of micro-roughened PEEK was about four times higher than that of the mirror-polished PEEK. These results showed that micro-roughening of PEEK using the sandblast method was able to improve osseointegration, partly through elevating proliferation and differentiation of RMSCs..
59. Toshiyuki Suge, Shingo Shibata, Kunio Ishikawa, Takashi Matsuo, Fluoride activity of antibacterial ammonium hexafluorosilicate solution for the prevention of dentin caries, American Journal of Dentistry, 31, 2, 103-106, 2018.04, Purpose: To evaluate the acid resistance of various antibacterial ammonium hexafluorosilicate (SiF) solutions. Methods: Antibacterial SiF solutions were prepared with the addition of chlorhexidine (CHX), cetylpyridinium chloride (CPC), isopropyl methylphenol (IPMP), or epigallocatechin gallate (EGCG). Hydroxyapatite pellets were treated with SiF solution with or without antibacterial agents for 3 minutes. The demineralized depth of hydroxyapatite pellets after SiF treatment was measured using a surface roughness analyzer. Results: SiF+CPC solution showed equivalent acid resistance to SiF and AgF treatment. In contrast, the original acid resistance activity of SiF solution was diminished by the addition of other antibacterial agents (CHX, IPMP and EGCG). SiF with the addition of CPC was the most effective for reducing the demineralized depth, showing the same levels as those of SiF and AgF..
60. Kunio Ishikawa, Tansza Setiana Putri, Akira Tsuchiya, Keisuke Tanaka, Kanji Tsuru, Fabrication of interconnected porous β-tricalcium phosphate (β-TCP) based on a setting reaction of β-TCP granules with HNO3 followed by heat treatment, Journal of Biomedical Materials Research - Part A, 10.1002/jbm.a.36285, 106, 3, 797-804, 2018.03, β-Tricalcium phosphate [β-TCP] is the typical bone substitute due to its excellent osteoconductivity and bioresorbability. One of the keys to improve its potential as bone substitute is to introduce porous structure and its regulation. In this study, interconnected porous β-TCP blocks were fabricated through a setting reaction of β-TCP granules and subsequent heat treatment. First, β-TCP granules were mixed with HNO3. Upon mixing, β-TCP granules were bridged with dicalcium phosphate dihydrate [DCPD: CaHPO4·2H2O] containing Ca(NO3)2. Then, the DCPD-bridged β-TCP was heated at 1100°C. During the heating process, DCPD containing Ca(NO3)2 transformed into β-TCP and bonded with β-TCP granules. As a result, an interconnected porous β-TCP block formed. The diametral tensile strength and porosity of the interconnected porous β-TCP block fabricated from 200–300-μm β-TCP granules and 5 N HNO3 and then heated at 1,100°C were 1.4 ± 0.2 MPa and 57% ± 2%, respectively..
61. Yuki Sugiura, Melvin L. Munar, Kunio Ishikawa, Fabrication of octacalcium phosphate foam through phase conversion and its histological evaluation, Materials Letters, 10.1016/j.matlet.2017.10.051, 212, 28-31, 2018.02, Octacalcium phosphate (OCP) foam with an interconnected porous structure was fabricated through phase conversion via a dissolution–precipitation reaction using calcium sulfate hemihydrate (CSH: CaSO4·1/2H2O) granules as precursors in a sodium dihydrogen phosphate (NaDP: NaH2PO4) solution. The diametral tensile strength and porosity of the OCP foam were 0.15 ± 0.04 MPa and 69.4% ± 0.04%, respectively. When the OCP foam was implanted into bone defects in a rabbit femur, the OCP foam showed an excellent tissue response, and the bone penetrated into the porous structure. The osteoconductivity and bone-replacement rate were significantly higher than those of an OCP compact..
62. Naoyuki Fukuda, Kanji Tsuru, Yoshihide Mori, Kunio Ishikawa, Fabrication of self-setting β-tricalcium phosphate granular cement, Journal of Biomedical Materials Research - Part B Applied Biomaterials, 10.1002/jbm.b.33891, 106, 2, 800-807, 2018.02, Bone defect reconstruction would be greatly improved if β-tricalcium phosphate (β-TCP) granules had the ability to self-set without sacrificing their osteoconductivity potential. This study aimed to identify a method to permit β-TCP self-setting whilst maintaining good osteoconductivity. When mixed with acidic calcium phosphate solution, β-TCP granules were found to readily set, forming a fully interconnected porous structure. On mixing, dicalcium phosphate dihydrate crystals formed on the surface of β-TCP granules, bridging the granules and resulting in the setting reaction. The setting time of the β-TCP granular cement (β-TCP GC) was approximately 1 min and its mechanical strength, in terms of diametral tensile strength, was approximately 0.8 MPa. The β-TCP GC and β-TCP granules both showed the same level of osteoconductivity within rat calvaria bone defects. At 2 and 4 weeks post-implantation, new bone formation was comparable between the two β-TCP based bone substitutes. We conclude that β-TCP GC has excellent potential for use as a cement in bone defect reconstruction..
63. Tya Indah Arifta, Melvin L. Munar, Kanji Tsuru, Kunio Ishikawa, Fabrication of interconnected porous calcium-deficient hydroxyapatite using the setting reaction of α tricalcium phosphate spherical granules, Ceramics International, 10.1016/j.ceramint.2017.05.162, 43, 14, 11149-11155, 2017.10, Interconnected porous calcium-deficient hydroxyapatite (cdHAp) blocks may be an ideal biomaterial to repair bone defects because of their greater similarity to human bone than that of sintered hydroxyapatite (HAp) with respect to calcium content and crystallinity. In particular, the interconnected pores in cdHAp may provide pathways for cell migration and tissue ingrowth. In this study, the feasibility of fabricating interconnected porous cdHAp blocks through the setting reaction of alpha-tricalcium phosphate (αTCP) spherical granules was investigated. It was found that regulation of cdHAp formation was important to fabricate interconnected porous cdHAp blocks. That is, cdHAp needed to precipitate preferentially at the contacting areas between αTCP spherical granules. Exposure of αTCP spherical granules to steam under appropriate pressure was effective for this purpose. When αTCP spherical granules were immersed in water at 100 °C, the setting reaction resulted in dense cdHAp blocks because of the free crystal growth of cdHAp in water. Therefore, steam was used to localize the water at the contacting areas between αTCP spherical granules, which was driven by the surface tension of the water. Without an applied load, no setting reaction was observed when αTCP spherical granules were exposed to steam at 100 °C for 12 h. In contrast, under a load of 20 MPa, cdHAp precipitated to bridge spherical granules, providing an interconnected porous cdHAp block. The porosity and diametral tensile strength of this block were approximately 63% and 1.5 MPa, respectively..
64. I. Grigoraviciute-Puroniene, K. Tsuru, E. Garskaite, Z. Stankeviciute, A. Beganskiene, Kunio Ishikawa, A. Kareiva, A novel wet polymeric precipitation synthesis method for monophasic β-TCP, Advanced Powder Technology, 10.1016/j.apt.2017.06.014, 28, 9, 2325-2331, 2017.09, β-Tricalcium phosphate (β-Ca3(PO4)2, β-TCP) powders were synthesized using wet polymeric precipitation method for the first time to our best knowledge. The results of X-ray diffraction analysis showed the formation of almost single a Ca-deficient hydroxyapatite (CDHA) phase of a poor crystallinity already at room temperature. With continuously increasing the calcination temperature up to 800 °C the crystalline β-TCP was obtained as the main phase. It was demonstrated that infrared spectroscopy is very effective method to characterize the formation of β-Ca3(PO4)2. The SEM results showed that β-Ca3(PO4)2 solids were homogeneous having a small particle size distribution. The β-TCP powders consisted of spherical particles varying in size from 100 to 300 nm. Fabricated β-TCP specimens were placed to the bones of the rats and maintained for 1–2 months. The histological properties of these samples will be also investigated..
65. Yuki Sugiura, Kanji Tsuru, Kunio Ishikawa, “Fabrication of arbitrarily shaped carbonate apatite foam based on the interlocking process of dicalcium hydrogen phosphate dihydrate”, Journal of Materials Science: Materials in Medicine, 10.1007/s10856-017-5937-0, 28, 8, 2017.08, Carbonate apatite (CO3Ap) foam with an interconnected porous structure is highly attractive as a scaffold for bone replacement. In this study, arbitrarily shaped CO3Ap foam was formed from α-tricalcium phosphate (α-TCP) foam granules via a two-step process involving treatment with acidic calcium phosphate solution followed by hydrothermal treatment with NaHCO3. The treatment with acidic calcium phosphate solution, which is key to fabricating arbitrarily shaped CO3Ap foam, enables dicalcium hydrogen phosphate dihydrate (DCPD) crystals to form on the α-TCP foam granules. The generated DCPD crystals cause the α-TCP granules to interlock with each other, inducing an α-TCP/DCPD foam. The interlocking structure containing DCPD crystals can survive hydrothermal treatment with NaHCO3. The arbitrarily shaped CO3Ap foam was fabricated from the α-TCP/DCPD foam via hydrothermal treatment at 200 °C for 24 h in the presence of a large amount of NaHCO3..
66. Wee Keat Cheah, Kunio Ishikawa, Radzali Othman, Fei Yee Yeoh, Nanoporous biomaterials for uremic toxin adsorption in artificial kidney systems
A review, Journal of Biomedical Materials Research - Part B Applied Biomaterials, 10.1002/jbm.b.33475, 105, 5, 1232-1240, 2017.07, Hemodialysis, one of the earliest artificial kidney systems, removes uremic toxins via diffusion through a semipermeable porous membrane into the dialysate fluid. Miniaturization of the present hemodialysis system into a portable and wearable device to maintain continuous removal of uremic toxins would require that the amount of dialysate used within a closed-system is greatly reduced. Diffused uremic toxins within a closed-system dialysate need to be removed to maintain the optimum concentration gradient for continuous uremic toxin removal by the dialyzer. In this dialysate regenerative system, adsorption of uremic toxins by nanoporous biomaterials is essential. Throughout the years of artificial kidney development, activated carbon has been identified as a potential adsorbent for uremic toxins. Adsorption of uremic toxins necessitates nanoporous biomaterials, especially activated carbon. Nanoporous biomaterials are also utilized in hemoperfusion for uremic toxin removal. Further miniaturization of artificial kidney system and improvements on uremic toxin adsorption capacity would require high performance nanoporous biomaterials which possess not only higher surface area, controlled pore size, but also designed architecture or structure and surface functional groups. This article reviews on various nanoporous biomaterials used in current artificial kidney systems and several emerging nanoporous biomaterials..
67. Masayuki Kanazawa, Kanji Tsuru, Naoyuki Fukuda, Yuta Sakemi, Yasuharu Nakashima, Kunio Ishikawa, Evaluation of carbonate apatite blocks fabricated from dicalcium phosphate dihydrate blocks for reconstruction of rabbit femoral and tibial defects, Journal of Materials Science: Materials in Medicine, 10.1007/s10856-017-5896-5, 28, 6, 2017.06, Abstract: This study aimed to evaluate in vivo behavior of a carbonate apatite (CO3Ap) block fabricated by compositional transformation via a dissolution–precipitation reaction using a calcium hydrogen phosphate dihydrate [DCPD: CaHPO4·2H2O] block as a precursor. These blocks were used to reconstruct defects in the femur and tibia of rabbits, using sintered dense hydroxyapatite (HAp) blocks as the control. Both the CO3Ap and HAp blocks showed excellent tissue response and good osteoconductivity. HAp block maintained its structure even after 24 weeks of implantation, so no bone replacement of the implant was observed throughout the post-implantation period in either femoral or tibial bone defects. In contrast, CO3Ap was resorbed with increasing time after implantation and replaced with new bone. The CO3Ap block was resorbed approximately twice as fast at the metaphysis of the proximal tibia than at the epiphysis of the distal femur. The CO3Ap block was resorbed at an approximately linear change over time, with complete resorption was estimated by extrapolation of data at approximately 1−1.5 years. Hence, the CO3Ap block fabricated in this study has potential value as an ideal artificial bone substitute because of its resorption and subsequent replacement by bone..
68. Khairul Anuar Shariff, Kanji Tsuru, Kunio Ishikawa, Fabrication of dicalcium phosphate dihydrate-coated β-TCP granules and evaluation of their osteoconductivity using experimental rats, Materials Science and Engineering C, 10.1016/j.msec.2017.03.004, 75, 1411-1419, 2017.06, β-Tricalcium phosphate (β-TCP) has attracted much attention as an artificial bone substitute owing to its biocompatibility and osteoconductivity. In this study, osteoconductivity of β-TCP bone substitute was enhanced without using growth factors or cells. Dicalcium phosphate dihydrate (DCPD), which is known to possess the highest solubility among calcium phosphates, was coated on β-TCP granules by exposing their surface with acidic calcium phosphate solution. The amount of coated DCPD was regulated by changing the reaction time between β-TCP granules and acidic calcium phosphate solution. Histomorphometry analysis obtained from histological results revealed that the approximately 10 mol% DCPD-coated β-TCP granules showed the largest new bone formation compared to DCPD-free β-TCP granules, approximately 2.5 mol% DCPD-coated β-TCP granules, or approximately 27 mol% DCPD-coated β-TCP granules after 2 and 4 weeks of implantation. Based on this finding, we demonstrate that the osteoconductivity of β-TCP granules could be improved by coating their surface with an appropriate amount of DCPD..
69. Kunio Ishikawa, Giichiro Kawachi, Kanji Tsuru, Ayami Yoshimoto, Fabrication of calcite blocks from gypsum blocks by compositional transformation based on dissolution–precipitation reactions in sodium carbonate solution, Materials Science and Engineering C, 10.1016/j.msec.2016.11.093, 72, 389-393, 2017.03, Calcium carbonate (CaCO3) has been used as a bone substitute, and is a precursor for carbonate apatite, which is also a promising bone substitute. However, limited studies have been reported on the fabrication of artificial calcite blocks. In the present study, cylindrical calcite blocks (ϕ6 × 3 mm) were fabricated by compositional transformation based on dissolution–precipitation reactions using different calcium sulfate blocks as a precursor. In the dissolution–precipitation reactions, both CaSO4·2H2O and CaSO4 transformed into calcite, a polymorph of CaCO3, while maintaining their macroscopic structure when immersed in 1 mol/L Na2CO3 solution at 80 °C for 1 week. The diametral tensile strengths of the calcite blocks formed using CaSO4·2H2O and CaSO4 were 1.0 ± 0.3 and 2.3 ± 0.7 MPa, respectively. The fabrication of calcite blocks using CaSO4·2H2O and CaSO4 proposed in this investigation may be a useful method to produce calcite blocks because of the self-setting ability and high temperature stability of gypsum precursors..
70. Kanji Tsuru, Ayami Yoshimoto, Masayuki Kanazawa, Yuki Sugiura, Yasuharu Nakashima, Kunio Ishikawa, Fabrication of carbonate apatite block through a dissolution-precipitation reaction using calcium hydrogen phosphate dihydrate block as a precursor, Materials, 10.3390/ma10040374, 10, 4, 2017.03, Carbonate apatite (CO3Ap) block, which is a bone replacement used to repair defects, was fabricated through a dissolution-precipitation reaction using a calcium hydrogen phosphate dihydrate (DCPD) block as a precursor. When the DCPD block was immersed in NaHCO3 or Na2CO3 solution at 80 °C, DCPD converted to CO3Ap within 3 days. β-Tricalcium phosphate was formed as an intermediate phase, and it was completely converted to CO3Ap within 2 weeks when the DCPD block was immersed in Na2CO3 solution. Although the crystal structures of the DCPD and CO3Ap blocks were different, the macroscopic structure was maintained during the compositional transformation through the dissolution-precipitation reaction. CO3Ap block fabricated in NaHCO3 or Na2CO3 solution contained 12.9 and 15.8 wt % carbonate, respectively. The diametral tensile strength of the CO3Ap block was 2 MPa, and the porosity was approximately 57% regardless of the carbonate solution. DCPD is a useful precursor for the fabrication of CO3Ap block..
71. Naoyuki Fukuda, Kanji Tsuru, Yoshihide Mori, Kunio Ishikawa, Effect of citric acid on setting reaction and tissue response to β-TCP granular cement, Biomedical Materials (Bristol), 10.1088/1748-605X/aa5aea, 12, 1, 2017.02, We recently reported that when an acidic calcium phosphate solution is mixed with β-tricalcium phosphate (β-TCP) granules, the resulting dicalcium phosphate dihydrate (DCPD) crystals form bridges between the β-TCP granules, creating a set interconnected porous structure in approximately 1 min. Although this self-setting β-TCP granular cement (β-TCPGC) is useful for clinical applications, the short setting time is a key drawback for handling. In this study, the setting time of β-TCPGC was adjusted with the addition of citric acid, which is a known inhibiter of DCPD crystal growth. As the concentration of citric acid in the acidic calcium phosphate solution increased, the amount of DCPD formation in the set β-TCPGC decreased, and the crystal morphology of DCPD became elongated. β-TCPGC prepared with various citric acid concentrations were used as grafting material in rat calvarial bone defects to evaluate bone regeneration in vivo. Four weeks after implantation, no inflammatory reaction and approximately 20% new bone formation were observed, regardless of the presence or absence of citric acid in the liquid phase of β-TCPGC. We concluded, therefore, that citric acid might be a useful retarder of β-TCPGC setting times..
72. Kunio Ishikawa, Development of carbonate apatite as artificial bone substitute, Japanese Magazine of Mineralogical and Petrological Sciences, 10.2465/gkk.161217, 46, 1, 42-46, 2017, Carbonate apatite (CO3Ap) that contains 6-9 wt% carbonate in apatitic structure is the composition of human bone. Unfortunately, CO3Ap cannot be sintered due to the presence of CO3. CO3Ap block was found to be fabricated based on a compositional transformation though dissolution-precipitation reaction using a precursor such as calcite block. CO3Ap block thus fabricated up-regulate the differentiation of osteoblastic cells and resorbed by the osteoclasts. As results of these response to cells, CO3Ap block demonstrate much better osteoconductivity than hydroxyapatite [HAp: Ca10(PO4)6(OH)2)] which is currently used artificial bone substitute. Also, CO3Ap block was found to be replace to new bone similar to autograft even though HAp would not replace to bone. Clinical trial of CO3Ap is now in progress, and CO3Ap will be available for its clinical use next year..
73. Yukie Shibata, Yoshihisa Yamashita, Kanji Tsuru, Kazuhiko Ishihara, Kyoko Fukazawa, Kunio Ishikawa, Preventive effects of a phospholipid polymer coating on PMMA on biofilm formation by oral streptococci, Applied Surface Science, 10.1016/j.apsusc.2016.08.108, 390, 602-607, 2016.12, The regulation of biofilm formation on dental materials such as denture bases is key to oral health. Recently, a biocompatible phospholipid polymer, poly(2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate) (PMB) coating, was reported to inhibit sucrose-dependent biofilm formation by Streptococcus mutans, a cariogenic bacterium, on the surface of poly(methyl methacrylate) (PMMA) denture bases. However, S. mutans is a minor component of the oral microbiome and does not play an important role in biofilm formation in the absence of sucrose. Other, more predominant oral streptococci must play an indispensable role in sucrose-independent biofilm formation. In the present study, the effect of PMB coating on PMMA was evaluated using various oral streptococci that are known to be initial colonizers during biofilm formation on tooth surfaces. PMB coating on PMMA drastically reduced sucrose-dependent tight biofilm formation by two cariogenic bacteria (S. mutans and Streptococcus sobrinus), among seven tested oral streptococci, as described previously [N. Takahashi, F. Iwasa, Y. Inoue, H. Morisaki, K. Ishihara, K. Baba, J. Prosthet. Dent. 112 (2014) 194–203]. Streptococci other than S. mutans and S. sobrinus did not exhibit tight biofilm formation even in the presence of sucrose. On the other hand, all seven species of oral streptococci exhibited distinctly reduced glucose-dependent soft biofilm retention on PMB-coated PMMA. We conclude that PMB coating on PMMA surfaces inhibits biofilm attachment by initial colonizer oral streptococci, even in the absence of sucrose, indicating that PMB coating may help maintain clean conditions on PMMA surfaces in the oral cavity..
74. Sunarso, Riki Toita, Kanji Tsuru, Ishikawa Kunio, Immobilization of calcium and phosphate ions improves the osteoconductivity of titanium implants., Mater Sci Eng C, org/10.1016/j.msec.2016.05.090, 68, 291-298, 2016.11.
75. Yuki Sugiura, Kanji Tsuru, Ishikawa Kunio, Fabrication of carbonate apatite pseudomorph from highly soluble acidic calcium phosphate salts through carbonation., J Ceram Soc Jpn, 10.2109/jcersj2.16046, 124, 8, 827-832, 2016.08.
76. Sunarso, Riki Toita, Kanji Tsuru, Ishikawa Kunio, A superhydrophilic titanium implant functionalized by ozone gas modulates bone marrow cell and macrophage responses., J Mater Sci: Mater Med, 10.1007/s10856-016-5741-2, 68, 291-298, 2016.08.
77. Khairul Anuar Shariff, Kanji Tsuru, Ishikawa Kunio, Fabrication of interconnected pore forming α-tricalcium phosphate foam granules cement., J Biomat Appl, 10.1177/0885328215601939, 30, 6, 838-845, 2016.06.
78. Koga Noriko, Ishikawa Kunio, Kanji Tsuru, Ichiro Takahashi, Effects of acidic calcium phosphate concentration on mechanical strength of porous calcite fabricated by bridging with dicalcium phosphate dihydrate., Ceram Int, org/10.1016/j.ceramint.2015.12.017, 42, 7, 7912-7917, 2016.05.
79. Ishikawa Kunio, Koga Noriko, Kanji Tsuru, Ichiro Takahashi, Fabrication of interconnected porous calcite by bridging calcite granules with dicalcium phosphate dihydrate and their histological evaluation., J Biomed Mater Res: Part A, 10.1002/jbm.a.35604, 104, 3, 652-658, 2016.05.
80. Masaaki Takechi, Yoshiaki Ninomiya, Kouji Ohta, Misato Tada, Kazuki Sasaki, Mohammad Zeshaan Rahman, Akira Ohta, Kanji Tsuru, Ishikawa Kunio, Effects of apatite cement containing atelocollagen on attachment to, and proliferation and differentiation of MC3T3-E1 osteoblastic cells., Materials, 10.3390/ma9040283, 9, 4, 283-283, 2016.04.
81. Shi Xingling, Xu L, Le Bang Thi, Zhou G, Zheng C, Kanji Tsuru, Ishikawa Kunio, Partial oxidation of TiN coating by hydrothermal treatment and ozone treatment to improve its osteoconductivity, Materials Science and Engineering: C, 10.1016/j.msec.2015.10.024, 59, 542-548, 2016.02.
82. Yuki Sugiura, Kanji Tsuru, Ishikawa Kunio, Fabrication of carbonate apatite foam based on the setting reaction of α-tricalcium phosphate foam granules., Ceram Int, org/10.1016/j.ceramint.2015.08.081, 42, 204-210, 2016.01.
83. 176. Siti Noorzidah Mohd Sabri, Synzana Abu Bakar, Abdul Yazid Abdul Manaf, Siti Frahana Hisham, Mohd Azmirrudin Ahmed, K. Jamuna Thevi, Kartini Norrsal, Hairul Anuar Shafiff, Ishikawa Kunio, Phase transformation of biphasic granules of gypsum and carbonated apatite at low temperatures., Adv Mater Res, 10.4028/www.scientific.net/AMR.1133.50 , 1133, 50-54, 2016.01.
84. Trung-Kien P, Ishikawa Kunio, Kanji Tsuru, Setting reaction of α-TCP spheres and an acidic calcium phosphate solution for the fabrication of fully interconnected macroporous calcium phosphate., Ceram Int, 10.1016/j.ceramint.2015.07.146, 41, 10, 13525-13531, 2015.12.
85. Riki Toita, Sunarso, Ahmed Nafis Rashid, Kanji Tsuru, Ishikawa Kunio, Modulation of the osteoconductive property and immune response of poly(ether ether ketone) by modification with calcium ions., J Mater Chem B, 10.1039/C5TB01679G, 3, 44, 8738-8746, 2015.10.
86. Noriko Koga, Kanji Tsuru, Ichiro Takahashi, Ishikawa Kunio, Effects of humidity on calcite block fabrication using calcium hydroxide compact. , Ceram Int, 41, 8, 9482-9487, 2015.09.
87. Kanji Tsuru, Ruslin, Shigeki Matsuya, Ishikawa Kunio, Effects of the method of apatite seed crystals addition on setting reaction of α-tricalcium phosphate based apatite cement., J Mater Sci: Mater Med, 10.1007/s10856-015-5570-8, 26, 244-451, 2015.09.
88. Rashid RN, Tsuru Kanji, Ishikawa Kunio, Effect of calcium-ozone treatment on chemical and biological properties of polyethylene terephthalate., J Biomed Mater Res: Part B, 3, 853-860, 2015.08.
89. Taro Nikaido, Kanji Tsuru, MUNAR MELVIN DE LEON, Michito Maruta, Shigeki Matsuya, Seiji Nakamura, Ishikawa Kunio, Fabrication of β-TCP foam: effects of magnesium oxide as phase stabilizer on its properties., Ceram Int, 41, 14245-14250, 2015.07.
90. ALIREZA VALANEZHAD, Kanji Tsuru, Ishikawa Kunio, Fabrication of strongly attached hydroxyapatite coating on titanium by hydrothermal treatment of Ti-Zn-PO4 coated titanium in CaCl2 solution., J Mater Sci: Mater Med, 10.1007/s10856-015-5548-6, 26, 7, 5548-5557, 2015.07.
91. Yasunori Ayukawa, Yumiko Suzuki, Takamori Y, Atsuta I, Nakamura H, Sawase T, Koyano K, Hara Y., Ishikawa Kunio, Kanji Tsuru, Histological comparison in rats between carbonate apatite fabricated from gypsum and sintered hydroxyapatite on bone remodeling., BioMed Res Int, 10.1155/2015/579541, Article ID 579541, 2015.07.
92. Cahyanto A, Maruta M, Kanji Tsuru, Matsuya S, Ishikawa Kunio, Fabrication of bone cement that fully transforms to carbonate apatite., Dent Mater J, 34, 3, 394-401, 2015.06.
93. Shi Xing Ling, Xu L, MUNAR MELVIN DE LEON, Ishikawa Kunio, Hydrothermal treatment for TiN as abrasion resistant dental implant coating and its fibroblast response., Materials Science and Engineering: C, 10.1016/j.msec.2014.12.059, 49, 1-6, 2015.04.
94. Ishikawa Kunio, Nguyen Xuan Thanh Tram, Kanji Tsuru, Toita Riki, Fabrication of porous calcite using chopped nylon fiber and its evaluation using rats., J Mater Sci: Mater Med, 26, 2, 94-101, 2015.02.
95. Ishikawa Kunio, Nagai H, Fujioka-Kobayashi M, Fujisawa K, Ohe G, Takamaru N, Hara K, Uchida D, Tamatani T, Miyamoto Y, Effects of low crystalline carbonate apatite on proliferation and osteoblastic differentiation of human bone marrow cells., J Mater Sci: Mater Med, 26, 2, 99-107, 2015.02.
96. Munar GM, MUNAR MELVIN DE LEON, Tsuru Kanji, Ishikawa Kunio, Effects of PLGA reinforcement methods on the mechanical property of carbonate apatite foam. , Bio-Medical Materials and Engineering, 24, 5, 1817-1825, 2014.05.
97. Ishikawa Kunio, Tsuru Kanji, Ichiro Takahashi, Fabrication of carbonate apatite block from set gypsum based on dissolution-precipitation reaction in phosphate-carbonate mixed solution., Dental Materials Journal, 33, (2), 166-172, 2014.03.
98. Nomura S, Tsuru Kanji, Matsuya S, Ichiro Takahashi, Ishikawa Kunio, Fabrication of carbonate apatite block from set gypsum based on dissolution-precipitation reaction in phosphate-carbonate mixed solution., Dent Mater J, 33(2): 166-172,, 33, (2): , 166-172, 2014.03.
99. Bang LT, Tsuru Kanji, Munar M, Ishikawa Kunio, Othman R, Mechanical behavior and cell response of PCL coated α-TCP foam for cancellous-type bone replacement. , Ceram Int, 39(5): 5631-5637, 39, (5): , 5631--5637, 2013.07.
100. Munar GM, Munar ML, Tsuru Kanji, Ishikawa Kunio, Influence of PLGA concentrations on structural and mechanical properties of carbonate apatite foam., Dent Mater J, 32(4):608-614, 32, (4):, 608--614, 2013.07.
101. Xingling Shi, Tsuru Kanji, Lingli Xu, Giichiro Kawachi, Ishikawa Kunio, Effects of solution pH on the structure and biocompatibility of Mg-containing TiO2 layer fabricated on titanium by hydrothermal treatment. , Applied Surface Science Vols.270, 270, 445-451, 2013.04.
102. Toshiyuki Suge, Kunio Ishikawa, Takashi Matsuo, Changes in the crystallinity of hydroxyapatite powder and structure of enamel treated with several concentrations of ammonium hexafluorosilicate., American Journal of Dentistry, 25(5): 299-302, 2012., 2012.10.
103. Kazuhiro Sunouchi, Kanji Tsuru, Michito Maruta, Giichiro Kawachi, Shigeki Matsuya, Yoshihiro Terada, Kunio Ishikawa, Fabrication of solid and hollow carbonate apatite microspheres as bone substitutes using calcite microspheres as a precursor., Dental Materials Journal, 31(4): 549-557, 2012., 2012.07.
104. Nurazreena Ahmad, Kanji Tsuru, Melvin L. Munar, Michito Maruta, Shigeki Matsuya, Kunio Ishikawa, Effect of precursor’s solubility on the mechanical property of hydroxyapatite formed by dissolution-precipitation reaction of tricalcium phosphate. , Dental Materials Journal, 31(4): 593-600, 2012., 2012.07.
105. Akihiro Otsu, Kanji Tsuru, Michito Maruta, Melvin L. Munar, Shigeki Matsuya, Kunio Ishikawa: , Fabrication of microporous calcite block from calcium hydroxide compact under carbon dioxide atmosphere at high temperature., Dental Materials Journal, 31(4): 593-600, 2012., 2012.07.
106. Shi X, Nakagawa M, Kawachi G, Xu L, Ishikawa K, Surface modification of titanium by hydrothermal treatment in Mg-containing solution and early osteoblast responses., J Mater Sci: Mater Med, 23:1281-1290, 2012., 2012.06.
107. Kawashita M, Taninai K, Li Z, Ishikawa K,•Yoshida Y, Preparation of low-crystalline apatite nanoparticles and their coating onto quartz substrates., J Mater Sci: Mater Med, 23: 1355-1362, 2012., 2012.06.
108. Sakai A, Valanezahad A, Ozaki M, Ishikawa K, Matsuya S, Preparation of Sr-containing carbonate apatite as a bone substitute and its properties., Dent Mater J, 31(2): 197-205, 2012., 2012.04.
109. Shibata S, Suge T, Kimura T, Ishikawa K, Matsuo T, Antibacterial activity of ammonium hexafluorosilicate solution with antimicrobial agents for the prevention of dentin caries., Am J Dent, 31(2): 197-205, 2012., 2012.02.
110. Valanezahad A, Tsuru K, Maruta M, Kawachi G, Matsuya S, Ishikawa K, A new biocompatible coating layer applied on titanium substrates using a modified zinc phosphatizing method., Surafce & Coating Tech, 206: 2207-2212, 2012., 2012.01.
111. Ishikawa Kunio, Kanji Tsuru, Fabrication of solid and hollow carbonate apatite microspheres as bone substitutes using calcite microspheres as a precursor., Dental Materials Journal, 31(4): 549-557, 2012., 2012.01.
112. Bang LT, Ishikawa K, Othman R, Effect of silicon and heat-treatment temperature on the morphology and mechanical properties of silicon - substituted hydroxyapatite., Ceram Int, 37(8): 3637-3642, 2011., 2011.12.
113. Valanezahad A, Ishikawa K, Tsuru K, Maruta M, Matsuya S, Hydrothermal calcium modification of 316L stainless steel and its apatite forming ability in simulated body fluid., Dent Mater J, 30(5), 749–753, 2011., 2011.10.
114. Mano T, Ishikawa K, Harada K, Umeda H, Ueyama Y, Comparison of apatite-coated titanium prepared by blast coating and flame spray methods -Evaluation using simulated body fluid and initial histological study, Dent Mater J, 30(4), 431-437, 2011., 2011.07.
115. Shibata S, Suge T, Ishikawa K, Matsuo T, Occlusion of dentin tubules with antibacterial ammonium hexafluorosilicate solution for the prevention of dentin caries., Am J Dent, 24: 148-152, 2011., 2011.06.
116. Maruta M, Matsuya S, Nakamura S, Ishikawa K, Fabrication of low-crystalline carbonate apatite foam bone replacement based on phase transformation of calcite foam., Dent Mater J, 30(1): 14-20, 2011., 2011.02.
117. Valanezhad A, Tsuru K, Maruta M, Kawachi G, Matsuya S, Ishikawa K, Zinc phosphate coating on 316L-type stainless steel using hydrothermal treatment., Surafce & Coating Tech, 205: 2538–2541, 2010., 2010.10.
118. Kien PT, Maruta M, Tsuru K, Matsuya S, Ishikawa K, Effect of phosphate solution on setting reaction of α-TCP spheres. , J Austrarian Ceram Soc, 46(2):63-67, 2010., 2010.10.
119. Matsumoto K, Tsuru K, Kawachi G, Maruta M, Matsuya S, Takahashi I, Ishikawa K, Reinforcement of carbonate apatite bone substitutes with carbonate apatite by Ca salt introduction., J Ceram Soc Jpn, 118(6): 521-524,2010., 2010.06.
120. Daitou F, Maruta M, Kawachi G, Tsuru K, Matsuya S, Terada Y, Ishikawa K, Fabrication of carbonate apatite block based on internal dissolution-precipitation reaction of dicalcium phosphate and calcium carbonate., Dent Mater J, 29(3): 303-308, 2010, 2010.06.
121. Zhang L, Ayukawa Y, LeGeros RZ, Matsuya S, Koyano K, Ishikawa K, Tissue-response to calcium-bonded titanium surface, J Biomed Mater Res: Part A, in press, 2010.05.
122. Tarique AAM, Tsuru K, Maruta M, Takeuchi A, Matsuya S, Terada Y, Ishikawa K, In vitro osteoconductivity evaluation of alumina treated hydrothermally in CaCl2 solution., J Ceram Soc Jpn, 118(6): 512-515, 2010, 2010.05.
123. Ishikawa K, Matsuya S, Lin X, Zhang L, Yuasa T, Miyamoto Y, Fabrication of low crystalline B-type carbonate apatite block from low crystalline calcite block, J Ceram Soc Jpn, 118(5): 341-344, 2010, 2010.05.
124. Udoh K, Munar ML, Maruta M, Matsuya S, Ishikawa K, Effects of sintering temperature on physical and compositional properties of α-tricalcium phosphate foam, Dent Mater J, 29(2): 154-159, 2010., 2010.03.
125. Suge T, Kawasaki A, Ishikawa K, Matsuo T, Ebisu S, Effects of ammonium hexafluorosilicate concentration on dentin tubule occlusion and composition of the precipitate, Dent Mater, 26(1): 29-34, 2010, 2010.01.
126. Shimogoryo R, Eguro T, Kimura E, Maruta M, Matsuya S, Ishikawa K, Effects of added mannitol on the setting reaction and mechanical strength of apatite cement, Dent Mater J, 28(5): 627-633, 2009., 2009.09.
127. Lowmunkong R, Sohmura T, Suzuki Y, Matsuya S, Ishikawa K, Fabrication of freeform bone-filling calcium phosphate ceramics by gypsum 3D printing method, J Biomed Mater Res B: Appl Biomater, 90(2), 531-539, 2009., 2009.08.
128. Takeuchi A, Munar ML, Wakae H, Maruta M, Matsuya S, Tsuru K, Ishikawa K, Effect of temperature on crystallinity of carbonate apatite foam prepared from α-tricalcium phosphate by hydrothermal treatment, Bio-Med Mater Eng, 19(2-3), 205–211, 2009, 2009.07.
129. Karashima S, Takeuchi A, Matsuya S, Udoh K, Koyano K, Ishikawa K, Fabrication of low-crystallinity hydroxyapatite foam based on the setting reaction of alpha-tricalcium phosphate foam, J Biomed Mater Res A. 88(3):628-633, 2009, 2009.03.
130. Zaman CT, Takeuchi A, Matsuya S, Zaman Q. H. M. S, Ishikawa K, abrication of B-type carbonate apatite blocks by the phosphorization of free-molding gypsum-calcite composite, Dent Mater J, 27(5): 710-715, 2008., 2008.05.
131. Kunio Ishikawa, Shigeki Matsuya, Masaharu Nakagawa, Koh-ichi Udoh and Kazuomi Suzuki, Basic properties of apatite cement containing spherical tetracalcium phosphate made with plasma melting method., Journal of Materials Science: Materials in Medicine, 10.1023/B:JMSM.0000010092.01661.a8, 15, 1, 13-17, 15(1), 13-17, 2004.01.
132. Satoru Tanaka, Tamisuke Kishi, Ryoji Shimogoryo, Shigeki Matsuya, Kunio Ishikawa, Biopex® acquires anti-washout properties by adding sodium alginate into its liquid phase., Dental Materials Journal, 22, 3, 301-312, 22(3), 301-312, 2003.01.
133. Yasuhiro Torii, Kousuke Itou, Yoshihiro Nishitani, Masahiro Yoshiyama, Kunio Ishikawa, Kazuomi Suzuki, Effect of self-setting primer containing N-acryloyl asparatic acid on enamel adhesion., Dental Materials, 19(4), 253-258, 2003.01.
134. Makoto Oda, Toshio Kaku, Atsushi Ookubo, Shigeki Matsuya, Kunio Ishikawa, The effects of hardening enviroment on the conversion to apatite and the mechanical strength of apatite cement., Journal of Japanese Society of Oral Implantology, 16(3), 400-408, 2003.01.
135. Ika Devi Ana, Shigeki Matsuya, Mihio Ohta, Kunio Ishikawa, Effects of added bioactive glass on the setting and mechanical properties of resin-modified glass ionomer cement., Biomaterials, 10.1016/S0142-9612(03)00151-0, 24, 18, 3061-3067, 24(18), 3061-3067, 2003.01.
136. Satoshi Nakabo, Yasuhiro Torii, Toshiyuki Itota, Kunio Ishikawa, Koji Miyazaki, Kazuomi Suzuki, Masahiro Yoshiyama, Effects of fluoride release from bis-GMA/TEGDMA resin regulated by γ-methacryloxypropyltrimethoxysilane on demineralization of bovine enamel., Biomaterials, 10.1016/S0142-9612(02)00079-0, 23, 16, 3503-3508, 23(16), 3503-3508, 2002.01.
137. Atsuo Ito, Haruo Kawamura, Makoto Otsuka, Masako Ikeuchi, Hajime Ohgushi, Kunio Ishikawa, Kazuo Onuma, Nariko Kanzaki, Yu Sogo, Noboru Ichinose, Zinc-releasing calcium phosphate for stimulating bone formation., Materials Science and Engineering C, 10.1016/S0928-4931(02)00108-X, 22, 1, 21-25, 22(1),1-25, 2002.01.
138. Yukihiro Momota, Youji Miyamoto, Kunio Ishikawa, Masaaki Takechi, Tetsuya Yuasa, Seiko Tatehara, Masaru Nagayama, Kazuomi Suzuki, Evaluation of feasibility of hydroxyapatite putty as a local hemostatic agent for bone., Journal of Biomedical Materials Research: Applied biomaterials, 10.1002/jbm.10332, 63, 5, 542-547, 63(5), 542 ? 547, 2002.01.
139. Yoshiya Ueyama, Kunio Ishikawa, Takamitsu Mano, Takahiro Koyama, Hitoshi Nagatsuka, Kazuomi Suzuki, Kazuo Ryoke, Usefulness as guided bone regeneration membrane of the alginate membrane., Biomaterials, 23(9), 2027-2033, 2002.01.
140. Yasuhiro Torii, Kousuke Itou, Yoshihiro Nishitani, Kunio Ishikawa, Kazuomi Suzuki, Effect of phosphoric acid etching prior to self-etching primer application on adhesion of resin composite to enamel and dentin., American Journal of Dentistry, 15(5): 305-308, 2002.01.
141. Toshiyuki Suge, Kunio Ishikawa, Akiko Kawasaki, Satoru Imazato, Yuichiro Noiri, Kazuomi Suzuki, Takashi Matsuo, Shigeyuki Ebisu, Calcium phosphate precipitation method for the treatment of dentin hypersensitivity., American Journal of Dentistry, 15, 4, 220-226, 15(4), 220-226, 2002.01.
142. Takamitsu Mano, Yoshiya Ueyama, Kunio Ishikawa, Kazuomi Suzuki, Tomohiro Matsumura, Initial tissue response to a titanium implant coated with apatite at room temperature using a blast coating method, Biomaterials, 23(9), 1931-1936, 2002.01.
143. Satoshi Nakabo, Yasuhiro Torii, Toshiyuki Itota, Masahiro Yoshiyama, Kunio Ishikawa, Kazuomi Suzuki, Regulation of fluoride ion release from Na2SiF6 contained in resin based on hydrophobic siloxane layer coating., Journal of Oral Rehabilitation, 29 (7), 675-681, 2002.01.
144. Satoshi Nakabo, Yasuhiro Torii, Toshiyuki Itota, Kunio Ishikawa, Kazuomi Suzuki, Regulation of NaF release from bis-GMA/TEGDMA resin using γ-methacryloxypropyltrimethoxysilane, Dental Materials, 18, 81-87, 2002.01.
145. Masaaki Takechi, Youji Miyamoto, Yukihiro Momota, Tetsuya Yuasa, Seikou Tatehara, Masaru Nagayama, Kunio Ishikawa, Kazuomi Suzuki, The in vitro antibiotic release from anti-washout apatite cement using chitosan., Journal of Materials Science: Materials in Medicine, 13(10), 973 ? 978, 2002.01.
146. Kunio Ishikawa, Youji Miyamoto, Taketomo Toh, Tetsuya Yuasa, Atsuo Ito, Masaru Nagayama, Kazuomi Suzuki, Fabrication of Zn containing apatite cement and its initial evaluation using human osteoblastic cells., Biomaterials, 23(2), 423-428, 2002.01.
147. Youji Miyamoto, Taketomo Toh, Kunio Ishikawa, Tetsuya Yuasa, Masaru Nagayama, Kazuomi Suzuki, Effect of added NaHCO3 on the basic properties of apatite cement., Journal of Biomedical Materials Research, 54(3), 311-319, 2001.01.
148. Yoshiya Ueyama, Kunio Ishikawa, Takamitsu Mano, Takahiro Koyama, Tomohiro Matsumura, Kazuomi Suzuki, Initial tissue response to anti-washout apatite cement in the rat palatal region: Comparison with conventional apatite cement., Journal of Biomedical Materials Research, 55(4), 652-660, 2001.01.
149. Tetsuya Yuasa, Youji Miyamoto, Kunio Ishikawa, Masaaki Takechi, Masaru Nagayama, Kazuomi Suzuki, In vitro resorption of three apatite cements with osteoclasts., Journal of Biomedical Materials Research, 54(3), 344-350, 2001.01.
150. Satoshi Nakabo, Yasuhiro Torii, Toshiyuki Itota, Masahiro Yoshiyama, Kunio Ishikawa, Kazuomi Suzuki, Effects of polysiloxane coating of NaF on the release profile of fluoride ion from bis-GMA/TEGDMA resin containing NaF, Dental Materilas Journal, 20(1), 53-62, 2001.01.
151. Masaaki Takechi, Kunio Ishikawa, Youji Miyamoto, Masaru Nagayama, Kazuomi Suzuki, Tissue responses to anti-washout apatite cement using chitosan when implanted in the rat tibia., Journal of Materials Science: Materials in Medicine, 12(7), 597-602, 2001.01.
152. Kousuke Itou, Yasuhiro Torii, Takehiko Takimura, Kana Chikami, Kunio Ishikawa, Kazuomi Suzuki, Effect of priming time on tensile bond strength to bovine tooth and morphological structure of interfaces created by self-etching primers, The International Journal of Prosthodontics, 14, 225-230, 2001.01.
153. Akiko Kawasaki, Kunio Ishikawa, Toshiyuki Suge, Hirotoshi Simizu, Kazuomi Suzuki, Takashi Matsuo, Shigeyuki Ebisu, Effects of plaque control on the occlusion of dentin tubule in situ., Journal of Oral Rehabilitation, 28(5), 439-449, 2001.01.
154. Teruo Kasai, Kunio Ishikawa, Kazuomi Suzuki, Hirofumi Yatani, Initial evaluation of a ceramic form as a reconstructive material for bone defect., Dental Materials Journal, 19(4), 381-388, 2000.01.
155. Kousuke Itou, Yasuhiro Torii, Yoshihiro Nishitani, Kunio Ishikawa, Kazuomi Suzuki, Kiyoshi Inoue, Effect of self-etching primers containing N-acryloyl aspartic acid on dentin adhesion., Journal of Biomedical Materials Research, 51(4), 569-574, 2000.01.
156. Kazuomi Suzuki, Kunio Ishikawa, Yoshihiro Nishitani, Kousuke Itou, Yasuhiro Torii, Norihiko Nishiyama, Kimiya Nemoto, Adhesion of restrative resin to teeth: Effects of functional groups of dentin primer to collagen, Dentistry in Japan, 36, 93-97, 2000.01.
157. Kazuomi Suzuki, Kunio Ishikawa, Katsumi Sugiyama, Hiroaki Furuta, Fumio Nishimura, Content and release of bisphenol A from polycarbonate dental products., Dental Materials Journal, 19(4), 389-395, 2000.01.
158. Guoqiang Guan, Teruko Takano-Yamamoto, Manabu Miyamoto, Tetsuo Hattori, Kunio Ishikawa, Kazuomi Suzuki, Shear bond strengths of orthodontic plastic brackets., American Journal of Orthodontics and Dentofacial Orthopedics, 117(4), 438-443, 2000.01.
159. Elisete Kazumi Watanabe, Hirofumi Yatani, Kunio Ishikawa, Kazuomi Suzuki, Atsushi Yamashita, Pilot study of conditioner/primer effects on resin-dentin bonding after provisional cement contamination using SEM, energy dispersive x-ray spectroscopy, and bond strength evaluation measures., The Journal of Prosthetic Dentistry, 83(3), 349-355, 2000.01.
160. Youji Miyamoto, Kunio Ishikawa, Masaaki Takechi, Taketomo Toh, Tetsuya Yuasa, Masaru Nagayama, Kazuomi Suzuki, Histological and compositional evaluations of three types of calcium phosphate cements when implanted in subcutaneous tissue immediately after mixing. Journal of Biomedical Materials, Research: Applied Biomaterials, 48(1), 36-42, 1999.01.
161. Toshiyuki Suge, Kunio Ishikawa, Akiko Kawasaki, Kazuomi Suzuki, Takashi Matsuo, Shigeyuki Ebisu, Evaluation of post-treatment solutions for clinical use with the calcium phosphate precipitation method., Journal of Dentistry, 27, 487-496, 1999.01.
162. Kunio Ishikawa, Youji Miyamoto, Masaaki Takechi, Yoshiya Ueyama, Kazuomi Suzuki, Masaru Nagayama, Tomohiro Matsumura, Effects of neutral sodium hydrogen phosphate on setting reaction and mechanical strength of hydroxyapatite putty, Journal of Biomedical Materials Research, 44(3), 322-329, 1999.01.
163. Kunio Ishikawa, Yoshiya Ueyama, Takamitsu Mano, Takahiro Koyama, Kazuomi Suzuki, Tomohiro Matsumura, Self-setting barrier membrane for guided tissue regeneration method: Initial evaluation of alginate membrane made with sodium alginate and calcium chloride aqueous solutions., Journal of Biomedical Materials Research, 47(2), 111-115, 1999.01.
164. Kunio Ishikawa, Shozo Takagi, Laurence C Chow, Kazuomi Suzuki, Reaction of calcium phosphate cements with different amounts of tetracalcium phosphate and dicalcium phosphate anhydrous., Journal of Biomedical Materials Research, 46(4), 504-510, 1999.01.
165. Jiro Tanaka, Kunio Ishikawa, Hirofumi Yatani, Atsushi Yamashita, Kazuomi Suzuki, Effect of carboxyl group in O-methacryloyl-N-acyl tyrosines on adhesiveness to unetched human dentin, Dental Materials Journal, 18(1), 87-95, 1999.01.
166. Jiro Tanaka, Kunio Ishikawa, Hirofumi Yatani, Atsushi Yamashita, Kazuomi Suzuki, Correlation of dentin bond durability with water absorption of bonding layer, Dental Materials Journal, 18(1), 11-18, 1999.01.
167. Elisete Kazumi Watanabe, Hirofumi Yatani, Atsushi Yamashita, Kunio Ishikawa, Kazuomi Suzuki, Effects of thermocycling on the tensile bond strength between resin cement and dentin surfaces after temporary cement application, International Journal of Prosthodontics, 12(3), 230-235, 1999.01.
168. Youji Miyamoto, Kunio Ishikawa, Masaaki Takechi, Taketomo Toh, Tetsuya Yuasa, Masaru Nagayama, Kazuomi Suzuki, Basic properties of calcium phosphate cement containing atelocollagen in its liquid or powder phases., Biomaterials, 19(8), 707-715, 1998.01.
169. Shozo Takagi, Laurence C Chow, Kunio Ishikawa, Formation of hydroxyapatite in new calcium phosphate cements, Biomaterials, 19(17), 1593-1599, 1998.01.
170. Masayuki Kon, Youji Miyamoto, Kenzo Asaoka, Kunio Ishikawa, Hae-Hyong Lee, Development of calcium phosphate cement for rapid crystallization to apatite, Dental Materials Journal, 17(4), 223-232, 1998.01.
171. Masaaki Takechi, Youji Miyamoto, Kunio Ishikawa, Taketomo Toh, Tetsuya Yuasa, Masaru Nagayama, Kazuomi Suzuki, Initial histological evaluation of anti-washout type fast-setting calcium phosphate cement following subcutaneous implantation, Biomaterials, 19(22), 2057-2063, 1998.01.
172. Masaaki Takechi, Youji Miyamoto, Kunio Ishikawa, Masaru Nagayama, Masayuki Kon, Kenzo Asaoka, Kazuomi Suzuki:, Effects of added antibiotics on the basic properties of anti-washout-type fast-setting calcium phosphate cement., Journal of Biomedical Materials Research, 39(2), 308-316, 1998.01.
173. Jiro Tanaka, Kunio Ishikawa, Hirofumi Yatani, Atsushi Yamashita, Kazuomi Suzuki, Steric effects of N-acryl group in O-methacryloyl-N-acyl tyrosines on the adhesiveness of unetched human dentin, Dental Materials Journal, 17(4), 233-238, 1998.01.
174. Elisete Kazumi Watanabe, Atsushi Yamashita, Hirofumi Yatani, Kunio Ishikawa, Kazuomi Suzuki, Improvement in the tensile bond strength between resin cement and dentin surfaces after temporary cement application., The International Journal of Prosthodontics, 11(3), 203-211, 1998.01.
175. Ishikawa Kunio, Tsuru Kanji, Effects of PLGA reinforcement methods on the mechanical property of carbonate apatite foam., Bio-Medical Materials and Engineering, in press..
176. Ishikawa Kunio, Effect of calcium-ozone treatment on chemical and biological properties of polyethylene terephthalate. , Journal of Biomedical Materials Research.
177. Ishikawa Kunio, Tsuru Kanji, Toita Riki, Fabrication of porous calcite using chopped nylon fiber and its evaluation using rats., Journal of Materials Science: Materials in Medicine.
178. Ishikawa Kunio, Tsuru Kanji, Toita Riki, Fabrication of porous calcite using chopped nylon fiber and its evaluation using rats., Journal of Materials Science: Materials in Medicine.
179. Ishikawa Kunio, Effects of low crystalline carbonate apatite on proliferation and osteoblastic differentiation of human bone marrow cells., Journal of Materials Science: Materials in Medicine.
180. Ishikawa Kunio, Tsuru Kanji, Ichiro Takahashi, Effects of humidity on calcite block fabrication using calcium hydroxide compact., Ceramics International.