How does hydroxyapatite

Should you look for a toothpaste that contains hydroxyapatite? Before you start scouring the store shelves, it's a good idea to speak with your dentist about your oral health concerns. If you have a history of sensitive teeth or weak enamel, a remineralising toothpaste might be a good option for you.

Your dentist can recommend the best toothpaste for you based on your current needs and oral health history. This article is intended to promote understanding of and knowledge about general oral health topics. It is not intended to be a substitute for professional advice, diagnosis or treatment. Always seek the advice of your dentist or other qualified healthcare provider with any questions you may have regarding a medical condition or treatment. Our Mission. Contact Us.

India English. Submit an Idea. Brand Logo. All rights reserved. Terms Of Use. Privacy Policy. About Our Ads. Children's Privacy Policy. Search Box Clear. Products Categories Goals Brands. Oral Health Education Our Commitment. Langmuir , 25 4 , — , DOI: The highly neg. Conversely, on the reacted surface, H2O adsorbs molecularly with BE similar to those computed for the surface.

C , 27 , — , DOI: Although the Ca-rich and P-rich HA nonstoichiometric surfaces exhibit different terminations, giving rise to different electrostatic features in the adsorption regions, glycine preferentially adsorbs as a zwitterion on both surfaces. When adsorbed in a canonical form, the proton of the COOH group is always transferred to the HA surface except for one case, which, in turn, is also the least stable one.

The harmonic B3LYP vibrational spectrum is in very good agreement with the exptl. The comparison also highlights that the Ca-rich rather than the P-rich termination is the most suitable to explain subtle features of the exptl. How does glycine adsorb at hydroxyapatite surfaces.

Royal Society. The AA adsorption was simulated on the and stoichiometric surfaces, the latter both in its pristine and water-reacted form. The interactions between the side chains and the HA surface impart a higher stability compared with the Gly case, with Glu being the strongest adsorbate owing to its high Ca affinity and H-bond donor propensity.

For AAs of large size, the adsorption is more favorable in conditions of low coverage as repulsion between adjacent AAs is avoided. For all considered AAs, the strongest interaction is always established on the faces rather than on the one, therefore suggesting an easier growth along the c-direction of HA crystals from AA solns. Large-scale periodic quantum mech. Adsorption as helix of both P1 and P2 mutants brings about proton transfer toward the HA surfaces with a large charge transfer component to the interaction energy.

Theory Comput. We studied the sensitivity of the energetic and geometrical features of the proline ring pyrrolidine to the quantum mech. Within the D. Functional Theory DFT approach, we tested the ability of different functionals GGA PBE and the hybrid B3LYP , added with a posteriori empirical dispersion corrections D , to predict the conformational potential energy surface of the five-membered heterocycle pyrrolidine ring for the above models, dictating the collagen main features.

We found that dispersion interactions are essential to destabilize specific conformers. While the HF-3c and its HF-3c variant are unreliable to predict accurately the energy of the ring conformers, structures are accurate. The adoption of either PBE or B3LYP functional for the electronic part of the DFT-D method gives very similar results, recommending the first as the most cost-effective method for simulating large collagen models.

The predicted most stable conformation computed for the periodic poly-proline type II model allows for a higher flexibility, in agreement with exptl. The present results open the way to large-scale calcns.

A quantum chem. Its main area of application is the computation of structures, vibrational frequencies, and noncovalent interaction energies in huge mol.

The method is suggested as a partial replacement of semiempirical approaches or d. In order to get accurate results three phys. In total nine global empirical parameters are used. This so-called Hartee-Fock-3c HF-3c method is tested for geometries of small org. In the majority of realistic test cases good results approaching large basis set DFT quality are obtained at a tiny fraction of computational cost. Quantum Chem. CRYSTAL14 is an ab initio code that uses a Gaussian-type basis set: both pseudopotential and all-electron strategies are permitted; the latter is not much more expensive than the former up to the first-second transition metal rows of the periodic table.

A variety of d. In particular, a very efficient implementation of global hybrids, such as popular B3LYP and PBE0 prescriptions, allows for such calcns.

The program can treat on the same grounds zero-dimensional mols. No spurious 3D periodicity is required for low-dimensional systems as happens when plane-waves are used as a basis set. Symmetry is fully exploited at all steps of the calcn. Three versions of the code exist, serial, parallel, and massive-parallel.

In the second one, the most relevant matrixes are duplicated, whereas in the third one the matrixes in reciprocal space are distributed for diagonalization. All the relevant vectors are now dynamically allocated and deallocated after use, making CRYSTAL14 much more agile than the previous version, in which they were statically allocated. The program now fits more easily in low-memory machines as many supercomputers nowadays are. Many tensorial properties can be evaluated in a fully automated way by using a single input keyword: elastic, piezoelec.

Many tools permit a complete anal. The IR and Raman intensities are now computed anal. Isotopic shifts are easily evaluated, frequencies of only a fragment of a large system computed and nuclear contribution to the dielec.

New algorithms have been devised for the investigation of solid solns. The topol. Generalized Gradient Approximation Made Simple. American Physical Society. Generalized gradient approxns. GGA's for the exchange-correlation energy improve upon the local spin d. LSD description of atoms, mols. We present a simple derivation of a simple GGA, in which all parameters other than those in LSD are fundamental consts.

Improvements over PW91 include an accurate description of the linear response of the uniform electron gas, correct behavior under uniform scaling, and a smoother potential. A new d. GGA type for general chem. A general computational scheme for the parameters used in this correction has been established and parameters for elements up to xenon and a scaling factor for the dispersion part for several common d. Further cross-validation tests were performed for organometallic reactions and other difficult problems for std.

The performance for noncovalently bound systems including many pure van der Waals complexes is exceptionally good, reaching on the av. CCSD T accuracy. The basic strategy in the development to restrict the d. As an example, for the isomerization of larger branched to linear alkanes, BD is the only DF available that yields the right sign for the energy difference.

From a practical point of view, the new functional seems to be quite robust and it is thus suggested as an efficient and accurate quantum chem. General Considerations. IMA J. New Approach to Variable Metric Algorithms. Optimal Conditioning of Quasi-Newton Methods. Special Points for Brillouin-Zone Integration. B , 13 , — , DOI: Prencipe, M. Springer GmbH. The vibrational spectrum of calcite CaCO3 is evaluated at an ab initio periodic quantum-mech.

The dynamical matrix is obtained by differentiating numerically the anal. The accuracy with respect to all computational parameters is documented. Overall, the agreement with expt.

An improved version of the direct inversion in the iterative subspace algorithm is developed. The method is significantly more efficient than the previous version, and is applicable to intrinsically divergent or slowly convergent cases.

Comparisons indicate that the method is superior to the recently proposed quadratically convergent QC-SCF method of G. Bacskay IR and Raman data. Nevertheless, the presence of one neg. A: At. Current gradient-cor. A gradient-cor. This functional, contg. Density-Functional Thermochemistry. The Role of Exact Exchange. The role of exact exchange. Despite the remarkable thermochem. Arguments to support this view are presented, and a semiempirical exchange-correlation functional contg.

This functional performs better than previous functionals with gradient corrections only, and fits expt. B: Condens. Matter Mater. A correlation-energy formula due to R. Colle and D. Salvetti , in which the correlation energy d. On insertion of gradient expansions for the local kinetic-energy d. Through numerical calcns. American Institute of Physics.

The method of dispersion correction as an add-on to std. Kohn-Sham d. The main new ingredients are atom-pairwise specific dispersion coeffs. The coeffs. System geometry dependent information is used for the first time in a DFT-D type approach by employing the new concept of fractional coordination nos. They are used to interpolate between dispersion coeffs.

The method only requires adjustment of two global parameters for each d. Three-body nonadditivity terms are considered. The method has been assessed on std. The mean abs. Spectacular improvements are found for a tripeptide-folding model and all tested metallic systems. The rectification of the long-range behavior and the use of more accurate C6 coeffs. We propose the revised DFT-D method as a general tool for the computation of the dispersion energy in mols.

The Force Between Nonpolar Molecules. Japan , 17 , Google Scholar There is no corresponding record for this reference. The interaction is calcd. Elsevier B. We present the Gaussian and plane waves GPW method and its implementation in which is part of the freely available program package CP2K. The GPW method allows for accurate d. We show how derivs. The computational cost of computing the total energy and the Kohn-Sham matrix is scaling linearly with the system size, even for condensed phase systems of just a few tens of atoms.

The efficiency of the method allows for the use of large Gaussian basis sets for systems up to atoms, and we illustrate the accuracy of the method for various basis sets in gas and condensed phases. Agreement with basis set free calcns. Wave function optimization with the orbital transformation technique leads to good parallel performance, and outperforms traditional diagonalisation methods.

Energy conserving Born-Oppenheimer dynamics can be performed, and a highly efficient scheme is obtained using an extrapolation of the d. We illustrate these findings with calcns. We generalize the concept of separable dual-space Gaussian pseudopotentials to the relativistic case. This allows us to construct this type of pseudopotential for the whole Periodic Table, and we present a complete table of pseudopotential parameters for all the elements from H to Rn.

The relativistic version of this pseudopotential retains all the advantages of its nonrelativistic version. It is separable by construction, it is optimal for integration on a real-space grid, it is highly accurate, and, due to its analytic form, it can be specified by a very small no.

The accuracy of the pseudopotential is illustrated by an extensive series of mol. Three recently proposed const. Hoover et al. Evans and G. Morris, 2 ; and J. Haile and S. Gupta, 3 ] are examd. Except for effects due to momentum and angular momentum conservation, method 1 yields the rigorous canonical distribution in both momentum and coordinate space.

Method 2 can be made rigorous in coordinate space, and can be derived from method 1 by imposing a specific constraint. The results for the const. Physical review. Molecular graphics on a personal computer. The program functions and examples of its application are presented. The user-friendly interface and the simple but powerful underlying logic are the main reasons for the widespread diffusion of MOLDRAW in the crystallog.

Graphics , 14 1 , 33 — 38 , DOI: VMD is a mol. VMD can simultaneously display any no. The atoms displayed in each representation are chosen using an extensive atom selection syntax, which includes Boolean operators and regular expressions.

VMD provides a complete graphical user interface for program control, as well as a text interface using the Tcl embeddable parser to allow for complex scripts with variable substitution, control loops, and function calls. Full session logging is supported, which produces a VMD command script for later playback. Hydroxyapatite is a rare material, in that it is a bioactive material , so it is one of the few lab-made materials that will help bones and teeth grow.

With recent developments in materials science and in nano-materials, there has been a fair amount of research and development dedicated to growing and finding the best uses for hydroxyapatite. Non-medical uses that have shown promise include air filtration to remove carbon dioxide and a filter to remove fluoride from saturated soil.

But, where hydroxyapatite really shines is in medical applications. Because it helps stimulate bone growth, nano hydroxyapatite is most frequently used in surgeries involving bones and tooth enamel. Joint replacement implants can be coated with nano hydroxyapatite.

The body is less likely to reject those implants, and the mineral coating encourages new bone growth around the implant, anchoring it more effectively. Calcium supplements of hydroxyapatite have shown early promise for maintaining bone health better than calcium carbonate supplements, although more research in this area is needed.

Tooth enamel is almost all hydroxyapatite. Oral care products that incorporate this mineral have greatly improved dental practices for patients. Dental implants that are coated in nano hydroxyapatite encourage bone growth and implant more effectively than non-coated implants. It can be added to dental filling agents used to repair serious cavities.