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Hydroxyapatite Crystals (hydroxyapatite + crystal)
Selected AbstractsNucleation of Hydroxyapatite Crystal through Chemical Interaction with CollagenJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2000Sang-Hoon Rhee The nucleation of hydroxyapatite (HAp) crystal through chemical interaction with collagen was investigated. A collagen membrane was soaked in a supersaturated simulated body fluid (1.5 SBF) solution with ion concentrations at 1.5 times that of normal simulated body fluid (1.0 SBF). A few carbonate-containing HAp crystals were formed mostly on the edge-side of the collagen membrane after 4 weeks. In the Fourier-transform infrared spectometry (FTIR) results, the carboxylate band of the collagen membrane showed red chemical shifts after the formation of HAp crystals, which coincided well with the decrease of the calculated bond orders of the carboxylate group when chelated with a calcium ion, which emulated the first-step nucleation of HAp crystal on the carboxylate group of collagen. The result implies that the binding of a calcium ion to the carboxylate group of collagen is one of the key factors for the nucleation of HAp crystals in a 1.5 SBF solution. [source] Biomineralization: Mussel-Inspired Polydopamine Coating as a Universal Route to Hydroxyapatite Crystallization (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 13 2010Mater. A universal biomineralization approach that can integrate hydroxyapatites on virtually any type and shape of substrate is presented. H. Lee, C. B. Park, and co-workers show on page 2132 that polydopamine, a catecholamine surface modifier inspired by adhesive proteins found in mussels, enriches calcium ions at the interface, facilitating the formation of biomimetic hydroxyapatite crystals. [source] Mussel-Inspired Polydopamine Coating as a Universal Route to Hydroxyapatite CrystallizationADVANCED FUNCTIONAL MATERIALS, Issue 13 2010Jungki Ryu Abstract Bone tissue is a complex biocomposite material with a variety of organic (e.g., proteins, cells) and inorganic (e.g., hydroxyapatite crystals) components hierarchically organized with nano/microscale precision. Based on the understanding of such hierarchical organization of bone tissue and its unique mechanical properties, efforts are being made to mimic these organic,inorganic hybrid biocomposites. A key factor for the successful designing of complex, hybrid biomaterials is the facilitation and control of adhesion at the interfaces, as many current synthetic biomaterials are inert, lacking interfacial bioactivity. In this regard, researchers have focused on controlling the interface by surface modifications, but the development of a simple, unified way to biofunctionalize diverse organic and inorganic materials remains a critical challenge. Here, a universal biomineralization route, called polydopamine-assisted hydroxyapatite formation (pHAF), that can be applied to virtually any type and morphology of scaffold materials is demonstrated. Inspired by the adhesion mechanism of mussels, the pHAF method can readily integrate hydroxyapatites on ceramics, noble metals, semiconductors, and synthetic polymers, irrespective of their size and morphology (e.g., porosity and shape). Surface-anchored catecholamine moieties in polydopamine enriches the interface with calcium ions, facilitating the formation of hydroxyapatite crystals that are aligned to the c -axes, parallel to the polydopamine layer as observed in natural hydroxyapatites in mineralized tissues. This universal surface biomineralization can be an innovative foundation for future tissue engineering. [source] Abfraction Lesions: Myth or Reality?JOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 5 2003J.S. REES BDS ABSTRACT Loss of tooth substance in the cervical region is usually attributed to toothbrush abrasion, erosion, or a combination of both factors. Recently the role of occlusal loading has become increasingly prominent. It is suggested that high occlusal loads cause large cervical stress concentrations, resulting in a disruption of the bonds between the hydroxyapatite crystals and the eventual loss of cervical enamel. This process has been called noncarious cervical tooth loss or abfraction. This article reviews the available evidence to support the thesis that occlusal loading can contribute to the process of abfraction. It also reviews the potential interactions between occlusal loading and erosion that may contribute to abfraction lesion formation. CLINICAL SIGNIFICANCE It is important to recognize the potential role of occlusal loading in the loss of cervical tooth tissue so that management of the occlusion can be incorporated into a treatment plan for a patient with abfraction lesions. [source] Calcium phosphate formation on the phosphorylated dental bonding agent in electrolyte solutionJOURNAL OF ORAL REHABILITATION, Issue 1 2004T. Hayakawa summary, The aim of the present study was to study the mineral formation on a phosphorylated dental bonding agent using a mineralization inductive solution. Clearfil Photobond, which contained phosphate monomer, was cured by photo-irradiation and heat treated, and was then immersed in Hanks' balanced salt solution (HBSS) with pH = 7·4 for 1, 3, 5, 7, 14, and 28 days at 37 °C. The white substances were deposited on the phosphorylated polymer, i.e. cured Photobond disk, after the immersion in HBSS. The white substances become visible after 3 days immersion. After 7 days immersion, surface of the phosphorylated polymer disk was almost covered with white substance layers. The measurement of white substances by means of X-ray diffraction, Fourier-transform infrared and electron probe microanalysis revealed that their main component was carbonate-containing hydroxyapatite. Scanning electron microscopy pictures showed that a large number of globules of hydroxyapatite were fused together, and that each globule was composed of a group of numerous thin-film form flakes uniting and/or clustering together. The results obtained in this study concluded that the presence of phosphonic acid and phosphate group of phosphorylated dental bonding agent enhanced the nucleation and growth of hydroxyapatite crystals on its surface. [source] Evaluation of enamel crystallites in subsurface lesion by microbeam X-ray diffractionJOURNAL OF SYNCHROTRON RADIATION, Issue 3 2009N. Yagi Early caries lesion is a demineralization process that takes place in the top 0.1,mm layer of tooth enamel. In this study, X-ray microbeam diffraction was used to evaluate the hydroxyapatite crystallites in the subsurface lesion of a bovine enamel section and the results are compared with those obtained by transversal microradiography, a method commonly used for evaluation of tooth mineral. Synchrotron radiation from SPring-8 was used to obtain a microbeam with a diameter of 6,µm. Wide-angle X-ray diffraction reports the amount of hydroxyapatite crystals, and small-angle X-ray scattering reports that of voids in crystallites. All three methods showed a marked decrease in the enamel density in the subsurface region after demineralization. As these diffraction methods provide structural information in the nanometre range, they are useful for investigating the mechanism of the mineral loss in early caries lesion at a nanometre level. [source] | |||||||||||||