DOI:10.14753/SE.2014.1974 Atomistic Origins of Fracture Toughness of Bioactive Glass Cement During Setting Ph.D dissertation Tian Kun Doctoral School of Clinical Medicine Semmelweis University Supervisor: Dr. Dobó Nagy, Csaba, professor, Ph.D Head of doctoral school Dr. Varga, Gábor, professor, doctor of the HAS, of clinical medicine: Ph.D Official reviewers: Dr. Turzó, Kinga, associate professor, Ph.D Dr. Kellermayer, Miklós, professor, doctor of the HAS, Ph.D Head of the final examination committee: Dr. Hermann, Péter, professor, Ph.D Members of the final Dr. Hegedűs, Csaba, professor, Ph.D examination committee: Dr. Fábián, Gábor, associate professor, Ph.D Budapest 2014 DOI:10.14753/SE.2014.1974 TABLE OF CONTENTS Content Page TABLE OF CONTENTS 1 ABBREVIATIONS AND SYMBOLS 4 PREAMBLE 6 1 INTRODUCTION 10 1.1 GIC applications 11 1.1.1 Dental applications 11 1.1.2 Applications outside dentistry 12 1.1.3 Potential applications 13 1.2 GIC structure 13 1.2.1 Macroscopic structure 13 1.2.2 Mesoscopic structure 13 1.2.3 Microscopic (Atomic & Molecular) structure 14 1.3 GIC properties 15 1.3.1 Physical properties of GICs 15 1.3.1.1 Appearance 15 1.3.1.2 Biocompatibility 15 1.3.1.3 Adhesion 16 1.3.1.4 Ion release 17 1.3.2 Mechanical properties of GICs 17 1.3.3 Changes in mechanical properties over time 19 1.4 GIC setting reactions (cementation) 20 1.4.1 Role of GIC powder 20 1.4.2 Action of GIC liquid 21 1.4.3 Setting reactions 22 1.4.4 Role of water 27 1.4.5 Role of fluorine 27 1.4.6 Role of tartaric acid 27 1.4.7 Role of phosphorous 28 1.4.8 Factors controlling reaction rate 29 1.5 The components of GICs 30 1.5.1 The glass component 30 1.5.1.1 Synthesis 30 1.5.1.2 Composition 30 1.5.1.3 Effect of particle size and distribution 32 1.5.1.4 Effect of alumina : silica ratio 32 1.5.1.5 Effect of sodium 33 1.5.1.6 Effect of fluorine 33 1.5.1.7 Effect of cation substitution 34 1.5.2 The liquid component 34 1.5.2.1 Synthesis 34 1.5.2.2 Composition 34 1 DOI:10.14753/SE.2014.1974 1.5.2.3 Influence of polyacrylic acid molecular weight 35 1.5.2.4 Influence of polyacrylic acid concentration 36 1.6 GIC characterisation techniques 36 1.6.1 Structural characterisation techniques 36 1.6.1.1Transmission Electron Microscopy (TEM) 37 1.6.1.2 Differential Scanning Calorimetry (DSC) 37 1.6.2 Setting mechanism characterisation techniques 38 1.6.2.1 NMR 38 1.6.3 Mechanical characterisation techniques 40 1.6.3.1 Fracture toughness test 40 1.6.3.2 Hertzian indentation test 43 1.6.3.3 Fractography 44 1.6.3.4 X-ray micro computed tomography (µCT) 44 1.7 Modifications to GICs 45 1.7.1 Modifications to the glass component 45 1.7.2 Modifications to the liquid component 47 1.7.2.1 Other copolymers 47 1.7.2.2 Resin modified GICs (RMGICs) 48 1.7.2.3 Acids other than polyacrylic acid 50 1.8 Novel techniques 50 1.8.1 Neutron spectroscopy 50 1.8.1.1 Fundamental background 51 1.8.1.2 Neutron Compton Scattering (NCS) 55 1.8.1.3 Neutron diffraction 61 1.8.2 Coherent Terahertz Spectroscopy (CTS) 65 1.8.3 Computational Modeling 66 2 DISSERTATION OBJECTIVES 68 3 MATERIALS AND METHODS 70 3.1 Mechanical testing and fractography 70 3.1.1 Sample preparation 70 3.1.2 Micro- and nanoCT imaging and data analysis 70 3.1.3 Hertzian indentation test 71 3.1.4 Complementary imaging 71 3.2 Neutron experiments 72 3.2.1 Neutron Compton scattering (NCS) experiments 72 3.2.2 Neutron diffraction experiments 74 3.3 Complementary experiments 75 3.3.1 DSC measurement 75 3.3.2 TEM measurement 75 3.3.3 CTS measurement 75 3.3.4 Computational Modeling 77 4 RESULTS 79 4.1 Mechanical testing and fractography 79 4.1.1 Hertzian indentation test 79 4.1.2 µCT imaging 79 2 DOI:10.14753/SE.2014.1974 4.1.3 Complementary imaging 81 4.2 Neutron experiments 82 4.2.1 Neutron Compton scattering (NCS) experiments 82 4.2.1.1 Forward scattering 82 4.2.1.2 Back scattering 85 4.2.1.3 Qualitative GIC NCS width 92 4.2.1.4 Conversion of NCS values to engineering units 94 4.2.2 Neutron diffraction experiments 96 4.3 Complementary experiments 100 4.3.1 Differential Scanning Calorimetry (DSC) 100 4.3.2 Transmission Electron Microscopy (TEM) 102 4.3.3 Coherent Terahertz Spectroscopy (CTS) 102 4.3.4 Computational Modeling 105 5 DISCUSSION 109 5.1 Mechanical testing and fractography 109 5.1.1 Hertzian indentation test 109 5.1.2 µCT imaging 110 5.1.3 Complementary imaging 111 5.2 Neutron experiments 112 5.2.1 Neutron Compton scattering (NCS) experiments 112 5.2.1.1 Forward scattering 113 5.2.1.2 Back scattering 115 5.2.1.3 Qualitative GIC NCS width 116 5.2.1.4 Conversion of NCS values to engineering units 116 5.2.2 Neutron diffraction experiments 119 5.3 Complementary experiments 121 5.3.1 Differential Scanning Calorimetry (DSC) 121 5.3.2 Transmission Electron Microscopy (TEM) 122 5.3.3 Coherent Terahertz Spectroscopy (CTS) 123 5.3.4 Computational Modeling 124 6 CONCLUSIONS 127 7 SUMMARY 133 8 ÖSSZEFOGLALÓ 134 9 REFERENCES 135 10 LIST OF PUBLICATIONS 154 11 ACKNOWLEDGEMENT 155 3 DOI:10.14753/SE.2014.1974 ABBREVIATIONS AND SYMBOLS ART Atraumatic Restorative Treatment ASPA AluminoSilicate PolyAcrylic ASTM American Society for Testing Materials BS British Standard CGIC Conventional Glass Ionomer Cement COO- Carboxylate Anion CTS Coherent Terahertz Spectroscopy DFT Density Functional Theory DGDZVP DGauss Double-Zeta Valence Polarization DINS Deep Inelastic Neutron Scattering DSC Differential scanning calorimetry ENS Elastic Neutron Scattering FSDP First Sharp Diffraction Peak FTIR Fourier Transform Infrared spectroscopy GIC Glass Ionomer Cement HEMA 2-hydroxyethyl methacrylate IA Itaconic Acid and Impulse Approximation ILL Institut Laue Langevin IR Infrared spectroscopy ISI Institute for Scientific Information ISO International Organization for Standardization KE Kinetic Energy KHN Knoop Hardness Number MAS Magic Angle Spinning MGA Methacryloyl Glutamic Acid NCS Neutron Compton Scattering NIMROD Near and InterMediate Range Order Diffractometer DNMRD Nuclear Magnetic Resonance NVP N-VinylPyrrolidone N/A Not Available OF (Harmonic) Oscillator Frequency PA PolyAcid PAA PolyAcrylic Acid PVPA poly vinyl phosphonic acid QO Quasi-Optical RMGIC Resin Modified Glass Ionomer Cement SANS Small Angle Neutron Scattering SEM Scanning Electron Microscopy SEN Single-Edge-Notch test SMI Structure Model Index TEM Transmission Electron Microscope TOF Time Of Flight VNA Vector Network Analyzer VOI Volume of Interest 4 DOI:10.14753/SE.2014.1974 WANS Wide Angle Neutron Scattering XRD X-Ray Diffraction YAP Yttrium Aluminium Perovskite µCT X-ray micro Computed Tomography 2-D 2 Dimensional ν Poisson's ratio KC Fracture toughness, also called critical stress intensity factor Q Magnitude of the momentum transfer vector of a scattered neutron F(Q) Total structure factor, used in neutron diffraction S(Q) Structure factor, is a mathematical description of how a material scatters r incidentDisplacement radiation in SANS, also a symbol for inter-atomic distance/bond g(r) lengthTotal radial distribution function D(r) Differential pair correlation function Cp Isobaric (constant pressure) heat capacity dB Insertion loss (decibel) used in Thz spectroscopy, equivalent to intensity Tg Glass transition temperature Δ Delta, Greek letter, denotes change d Latin letter, denotes derivatives and differentials pH Is a measure of the acidity or basicity of an aqueous solution n(p) Momentum distribution In situ Latin for "in position," to examine the phenomenon exactly in place where In vivo itLatin occurs for "within the living," is experimentation using a whole, living Pa organismPascal, pressure unit Å Angstrom, length unit, equals 10-10 meter N Newton, force unit -3 m Meter, length unit; milli, unit prefix, 10 m2 Square meter, area unit fm Femto, unit prefix, equals 10-15 Micro, unit prefix, equals 10-6 c Centi, unit prefix, equals 10-2 k Kilo, unit prefix, equals 103 M Mega, unit prefix, equals 106 G Giga, unit prefix, equals 109 T Tera, unit prefix , equals 1012 eV Electron volt, energy unit, the amount of energy gained (or lost) by the V Volt,charge unit of afor single electric electron potential moved across an electric potential difference of % Percentageone volt sign, fraction of 100 sec/s Second, time unit min Minute, time unit, equals 60 seconds hr/h Hour, time unit, equals 60 minutes d Day, time unit, equals 24 hours m Month,single electron time unit, moved equals across 30/31 an days electric potential difference of one volt. Hz Hertz, frequency unit, the number of cycles per second of a periodic Amp phenomenonAmpere, electric current unit L Litre, volume unit ppm Parts per million, denotes one part per 1,000,000 parts 5 DOI:10.14753/SE.2014.1974 PREAMBLE The history of implanting foreign materials into the human body can be traced back to ancient civilisations seeking replacements for missing or damaged teeth. The earliest known example for which there is firm archeological evidence involves endosseous implants dating back to ~600 AD [1] by the Maya [~2000 BC – 1697 AD]. These included fossils of human mandibles adorned with three tooth-shaped pieces of shell placed into the sockets of three missing lower incisor teeth.