Nanoscale osseointegration of zirconia evaluated from the interfacial structure between ceria-stabilized tetragonal zirconia and cell-induced hydroxyapatite.

Background: The osseointegration of zirconia implants has been evaluated based on their implant fixture bonding with the alveolar bone at the optical microscopic level. Achieving nano-level bonding between zirconia and bone apatite is crucial for superior osseointegration; however, only a few studies have investigated nanoscale bonding. This review outlines zirconia osseointegration, including surface modification, and presents an evaluation of nanoscale zirconia-apatite bonding and its structure.

Synergistic effect of FGF-2 and TGF-β1 on the mineralization of human umbilical cord perivascular cells.

Objective: Human umbilical cord perivascular cells (HUCPVCs) are derived from the human umbilical cord perivascular tissue and are expected to replace mesenchymal stromal cells in the future. We investigated the synergistic effects of fibroblast growth factor 2 (FGF-2) and transforming growth factor-beta 1 (TGF-β1) on HUCPVC mineralization.

Design: We prepared HUCPVCs with (FGF(+)HUCPVCs) or without FGF-2 (FGF(-)HUCPVCs) in the presence of activated vitamin D, a bone morphogenic protein inhibitor, and TGF-β1.

Cementum is key to periodontal tissue regeneration: A review on apatite microstructures for creation of novel cementum-based dental implants.

The cementum is the outermost layer of hard tissue covering the dentin within the root portion of the teeth. It is the only hard tissue with a specialized structure and function that forms a part of both the teeth and periodontal tissue. As such, cementum is believed to be critical for periodontal tissue regeneration.

Repurposing MDZ as a tool for tissue regeneration in dental cells.

Background: Several recent studies have focused on the utility of drug repurposing to expand clinical application of approved therapeutics. Here, we investigate the efficacy of midazolam (MDZ) and cytokines for regenerating calcified tissue, using immortalized porcine dental pulp (PPU7) and mouse skeletal muscle derived myoblast (C2C12) cells, with the goal of repurposing MDZ as a new treatment to facilitate calcified tissue regeneration.

Highlights: We noted that PPU7 and C2C12 cells cultured with various MDZ regimens displayed increased bone morphogenic protein (BMP-2), transforming growth factor beta (TGF-β), and alkaline phosphatase activity.

Coherent surface structure induces unique epitaxial overgrowth of metastable octacalcium phosphate on stable hydroxyapatite at critical fluoride concentration.

The phase transformation from soluble calcium phosphates to less-soluble hydroxyapatite (HAP) is a thermodynamically natural route. This process is irreversible, and effective use of poorly reactive HAP to repair teeth that have no cellular metabolism remains challenging. However, this thermodynamically controlled transformation may apparently be reversed through the fast nucleation and growth of metastable phases, leading to a reactive HAP surface.

New insights into bioactivity of ceria-stabilized zirconia: Direct bonding to bone-like hydroxyapatite at nanoscale.

Osseointegration resulting from biomineralization means tight bone-implant attachment, which is clinically essential for successful dental implant treatment. The osseointegration ability of ceria-stabilized zirconia, a promising implant material, has been questionable and is unclear despite its clinical use due to zirconia's bioinert nature. The purpose of this research was to investigate the osseointegration ability of ceria-stabilized zirconia by clarifying its bioactivity.

Combined Effect of Midazolam and Bone Morphogenetic Protein-2 for Differentiation Induction from C2C12 Myoblast Cells to Osteoblasts.

In drug repositioning research, a new concept in drug discovery and new therapeutic opportunities have been identified for existing drugs. Midazolam (MDZ) is an anesthetic inducer used for general anesthesia. Here, we demonstrate the combined effects of bone morphogenetic protein-2 (BMP-2) and MDZ on osteogenic differentiation.

Potential for Drug Repositioning of Midazolam for Dentin Regeneration.

Drug repositioning promises the advantages of reducing costs and expediting approvalschedules. An induction of the anesthetic and sedative drug; midazolam (MDZ), regulatesinhibitory neurotransmitters in the vertebrate nervous system. In this study we show the potentialfor drug repositioning of MDZ for dentin regeneration.

Artificial enamel induced by phase transformation of amorphous nanoparticles.

Human tooth enamel has tightly packed c-axis-oriented hydroxyapatite (HAP: Ca(PO)(OH)) nanorods with high elastic modulus. Fabrication of an enamel architecture in vitro supports the repair of teeth using HAP; however, existing methods require complex and laborious steps to form an enamel-like structure. Here we present a very simple and effective technique for forming artificial enamel in near-physiological solution using a substrate composed of amorphous calcium phosphate (ACP) nanoparticles.

TGF-β1 autocrine signalling and enamel matrix components.

Transforming growth factor-β1 (TGF-β1) is present in porcine enamel extracts and is critical for proper mineralization of tooth enamel. Here, we show that the mRNA of latent TGF-β1 is expressed throughout amelogenesis. Latent TGF-β1 is activated by matrix metalloproteinase 20 (MMP20), coinciding with amelogenin processing by the same proteinase.

Zn- and Mg- containing tricalcium phosphates-based adjuvants for cancer immunotherapy.

Zn-, and Mg-containing tricalcium phosphates (TCPs) loaded with a hydrothermal extract of a human tubercle bacillus (HTB) were prepared by immersing Zn-TCP and Mg-TCP in HTB-containing supersaturated calcium phosphate solutions. The in vitro and in vivo immunogenic activities of the HTB-loaded Zn-, and Mg-TCPs (Zn-Ap-HTB and Mg-Ap-HTB, respectively) were evaluated as potential immunopotentiating adjuvants for cancer immunotherapy. The Zn-Ap-HTB and Mg-Ap-HTB adjuvants showed no obvious cytotoxicity and more effectively stimulated granulocyte-macrophage colony-stimulating factor (GM-CSF) secretion by macrophage-like cells than unprocessed HTB or HTB-loaded TCP (T-Ap-HTB) in vitro.

Mesoporous silica-calcium phosphate-tuberculin purified protein derivative composites as an effective adjuvant for cancer immunotherapy.

The synthesis of mesoporous silica/calcium phosphate composite loaded with the immunopotentiator tuberculin purified protein derivative (PPD-MS/CaP) as an effective adjuvant for cancer immunotherapy is reported here. The PPD-MS/CaP adjuvant is prepared by immersing mesoporous silica in a supersaturated calcium phosphate solution supplemented with the immunopotentiator PPD for 24 h. PPD is coprecipitated with calcium phosphate inside and on the surface of mesoporous silica.

Generation of gaseous sulfur-containing compounds in tumour tissue and suppression of gas diffusion as an antitumour treatment.

Background And Aims: The mechanisms of cancer cell growth and metastasis are still not entirely understood, especially from the viewpoint of chemical reactions in tumours. Glycolytic metabolism is markedly accelerated in cancer cells, causing the accumulation of glucose (a reducing sugar) and methionine (an amino acid), which can non-enzymatically react and form carcinogenic substances. There is speculation that this reaction produces gaseous sulfur-containing compounds in tumour tissue.

Direct transformation from amorphous to crystalline calcium phosphate facilitated by motif-programmed artificial proteins.

An animal's hard tissue is mainly composed of crystalline calcium phosphate. In vitro, small changes in the reaction conditions affect the species of calcium phosphate formed, whereas, in vivo, distinct types of crystalline calcium phosphate are formed in a well-controlled spatiotemporal-dependent manner. A variety of proteins are involved in hard-tissue formation; however, the mechanisms by which they regulate crystal growth are not yet fully understood.

Association kinetics of wild- and mutant-type Ynd1p in relation to quality of grown crystals.

The intermolecular interaction and association dynamics of the Ynd1p protein were investigated using dynamic and time-resolved static light scattering measurements. The mutual diffusion coefficients of wild- and mutant-type (a single amino acid substitution) Ynd1p monomer were measured in 50 mM 2-(N-morpholino)ethanesulfonic acid (MES) buffer with 5 mM MnCl2 and 7.5% (v/v) ethylene glycol.

Effect of phosvitin on the nucleation and growth of calcium phosphates in physiological solutions.

The promoting effect of phosvitin on the nucleation of hydroxyapatite (HAP) and the inhibitory effect of phosvitin on the transformation from amorphous calcium phosphate (ACP) to HAP were investigated. Atomic force microscopy observations showed that the nucleation of HAP on collagen substrate was greatly enhanced when the phosvitin was bound on the collagen surface. Nucleated crystals were uniformly distributed with a high nucleation rate on the collagen surface in the presence of phosvitin, while, in the absence of phosvitin, crystals nucleated slowly and were observed only at some particular area.

Intermolecular interaction of actin revealed by a dynamic light scattering technique.

The intermolecular interaction force of actin was studied by a dynamic light scattering technique. The mutual diffusion coefficients (D) of monomeric actin were accurately determined in a G-buffer with a low concentration of KCl from 0 to 10 mM. The translational diffusion coefficient was obtained as D(0) = (87 +/- 3) x 10(-12) m(2).

Spontaneous growth of a laminin-apatite nano-composite in a metastable calcium phosphate solution.

We have previously reported that a laminin-apatite composite layer is formed on an ethylene-vinyl alcohol copolymer (EVOH) in a laminin-containing calcium phosphate (LCP) solution. In this work, the stability of the LCP solution and growth process of the laminin-apatite composite layer have been investigated. Dynamic light scattering technique revealed that the LCP solution was stable for periods as long as 24 h; it did not induce homogeneous precipitation of laminin or calcium phosphates in the solution.

Materials chemistry: a synthetic enamel for rapid tooth repair.

The conventional treatment of dental caries involves mechanical removal of the affected part and filling of the hole with a resin or metal alloy. But this method is not ideal for tiny early lesions because a disproportionate amount of healthy tooth must be removed to make the alloy or resin stick. Here we describe a dental paste of synthetic enamel that rapidly and seamlessly repairs early caries lesions by nanocrystalline growth, with minimal wastage of the natural enamel.

Association of calcium phosphate and fibroblast growth factor-2: a dynamic light scattering study.

The size distributions of fibroblast growth factor-2 (FGF-2) in aqueous solutions with neutral pH were investigated with a dynamic light scattering technique. We found that the FGF-2 was distributed in dimer or trimer form at concentrations of 0.1-1.

Rationalization of membrane protein crystallization with polyethylene glycol using a simple depletion model.

Based on the importance of crystallizing membrane proteins in a rational way, cytochrome bc(1) complex (BC1) was crystallized using polyethylene glycol (PEG) as a sole crystallization agent. Interaction between protein-detergent complexes of BC1 was estimated by dynamic light scattering, and was compared with the numerical calculation using the Derjaguin-Landau-Verwey-Overbeek potential plus a depletion potential, without considering specific surface properties of the protein-detergent complexes. The experiments and calculation were found to be consistent and we obtained a relation between PEG molecular weight M and the range of depletion zone delta as delta approximately M(0.

Formation and growth of clusters in conventional and new kinds of simulated body fluids.

Simulated body fluid (SBF) with ion concentrations approximately equal to those of human blood plasma has been widely used for the in vitro assessment of the bioactivity of artificial materials and for the formation of bonelike apatite on various substrates. Ion concentrations of conventional SBF (c-SBF) are, however, not exactly equal to those of blood plasma, and hence the apatite formed in c-SBF is not the same as bone apatite in its composition and structure. Recently, the present authors prepared new kinds of SBFs (r-SBF, i-SBF, and m-SBF) with ion concentrations nearer to those of blood plasma.

The most appropriate (Ca+Zn)/P molar ratio to minimize the zinc content of ZnTCP/HAP ceramic used in the promotion of bone formation.

The (Ca+Zn)/P molar ratio of zinc-containing tricalcium phosphate and hydroxyapatite composite ceramics (ZnTCP/HAP) was investigated in the range from 1.50 to 1.66 to reveal the minimum zinc content possible in ceramics used in the promotion of osteoblastic cell proliferation and bone formation.

Resorbability and solubility of zinc-containing tricalcium phosphate.

Using zinc-containing tricalcium phosphate (ZnTCP) as the zinc carrier for zinc-releasing calcium phosphate ceramic implants promoted bone formation around the implants. Because no quantitative information was available on the equilibrium solubility and resorbability of ZnTCP, in vitro equilibrium solubility and in vivo resorbability of ZnTCP were determined and compared quantitatively in this study. The solubility of ZnTCP decreased with increasing zinc content.