Roles of Fluoride on Octacalcium Phosphate and Apatite Formation on Amorphous Calcium Phosphate Substrate

2018 ◽  
Vol 18 (4) ◽  
pp. 2279-2288 ◽  
Author(s):  
Mayumi Iijima ◽  
Kazuo Onuma
Keyword(s):  
Calcium Phosphate ◽  
Amorphous Calcium Phosphate ◽  
Octacalcium Phosphate ◽  
Apatite Formation

Osteoconductive Property of a Mechanical Mixture of Octacalcium Phosphate and Amorphous Calcium Phosphate

2014 ◽  
Vol 6 (24) ◽  
pp. 22602-22611 ◽  
Author(s):  
Kazuhito Kobayashi ◽  
Takahisa Anada ◽  
Takuto Handa ◽  
Naofumi Kanda ◽  
Mariko Yoshinari ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Amorphous Calcium Phosphate ◽  
Octacalcium Phosphate ◽  
Mechanical Mixture ◽  
Osteoconductive Property

scholarly journals Phosphoserine Functionalized Cements Preserve Metastable Phases, and Reprecipitate Octacalcium Phosphate, Hydroxyapatite, Dicalcium Phosphate, and Amorphous Calcium Phosphate, during Degradation, In Vitro

2019 ◽  
Vol 10 (4) ◽  
pp. 54 ◽  
Author(s):  
Joseph Lazraq Bystrom ◽  
Michael Pujari-Palmer
Keyword(s):  
Calcium Phosphate ◽  
Amorphous Calcium Phosphate ◽  
Octacalcium Phosphate ◽  
Ionic Concentration ◽  
Strong Adhesion ◽  
Acidic Conditions ◽  
Rapid Transformation ◽  
Comparable Mass

Phosphoserine modified cements (PMC) exhibit unique properties, including strong adhesion to tissues and biomaterials. While TTCP-PMCs remodel into bone in vivo, little is known regarding the bioactivity and physiochemical changes that occur during resorption. In the present study, changes in the mechanical strength and composition were evaluated for 28 days, for three formulations of αTCP based PMCs. PMCs were significantly stronger than unmodified cement (38–49 MPa vs. 10 MPa). Inclusion of wollastonite in PMCs appeared to accelerate the conversion to hydroxyapatite, coincident with slight decrease in strength. In non-wollastonite PMCs the initial compressive strength did not change after 28 days in PBS (p > 0.99). Dissolution/degradation of PMC was evaluated in acidic (pH 2.7, pH 4.0), and supersaturated fluids (simulated body fluid (SBF)). PMCs exhibited comparable mass loss (<15%) after 14 days, regardless of pH and ionic concentration. Electron microscopy, infrared spectroscopy, and X-ray analysis revealed that significant amounts of brushite, octacalcium phosphate, and hydroxyapatite reprecipitated, following dissolution in acidic conditions (pH 2.7), while amorphous calcium phosphate formed in SBF. In conclusion, PMC surfaces remodel into metastable precursors to hydroxyapatite, in both acidic and neutral environments. By tuning the composition of PMCs, durable strength in fluids, and rapid transformation can be obtained.

The Influence of Fluoride on Apatite Formation from Unstable Supersaturated Solutions at pH 7.4

1978 ◽  
Vol 57 (4) ◽  
pp. 617-624 ◽  
Author(s):  
E.D. Eanes ◽  
J.L. Meyer
Keyword(s):  
Calcium Phosphate ◽  
Octacalcium Phosphate ◽  
Apatite Formation ◽  
Supersaturated Solutions ◽  
Precursor Phases

The present study was undertaken to examine the effect of fluoride on the formation of apatite in aqueous calcium phosphate suspensions prepared by spontaneous precipitation at pH 7.4. The most notable finding was that fluoride greatly curtailed or eliminated the appearance of octacalcium phosphate-like precursor phases in these preparations.

The Role of Brushite and Octacalcium Phosphate in Apatite Formation

1992 ◽  
Vol 3 (1) ◽  
pp. 61-82 ◽  
Author(s):  
Mats S.-A. Johnsson ◽  
George H. Nancollas
Keyword(s):  
Calcium Phosphate ◽  
Octacalcium Phosphate ◽  
In Vivo Studies ◽  
Apatite Formation ◽  
Acidic Solutions ◽  
Phosphate Phase ◽  
Apatite Mineral

Studies of apatite mineral formation are complicated by the possibility of forming several calcium phosphate phases. The least soluble, hydroxyapatite (HAP), is preferentially formed under neutral or basic conditions. In more acidic solutions phases such as dicalcium phosphate dihydrate (Brushite, DCPD) and octacalcium phosphate (OCP) are often found. Even under ideal HAP precipitation conditions the precipitates are generally nonstoichiometric, suggesting the formation of calcium-deficient apatites. Both DCPD and OCP havea been implicated as possible precursors to the formation of apatite. This may occur by the initial precipitation of DCPD and/or OCP followed by transformation to a more apatitic phase. Although DCPD and OCP are often detected during in vitro crystallization, in vivo studies of bone formation rarely show the presence of these acidic calcium phosphate phases. In the latter case the situation is more complicated, since a large number of ions and molecules are present that can be incorporated into the crystal lattice or adsorbed at the crystallite surfaces. In biological apatite, DCPD and OCP are usually detected only during pathological calcification where the pH is often relatively low. In normal in vivo calcifications these phases have not been found, suggesting the involvement of other precursors or the formation of an initial amorphous calcium phosphate phase (ACP) followed by transformation to apatite.

Ultrastructural, Elemental and Mineralogical Analysis of Vascular Calcification in Atherosclerosis

2017 ◽  
Vol 23 (5) ◽  
pp. 1030-1039 ◽  
Author(s):  
Ida Perrotta ◽  
Edoardo Perri
Keyword(s):  
Calcium Phosphate ◽  
Vascular Calcification ◽  
Amorphous Calcium Phosphate ◽  
Matrix Vesicles ◽  
Structural Features ◽  
Human Aorta ◽  
Apatite Formation ◽  
Cellular Mechanisms ◽  
Microscopy Imaging ◽  
Mineral Deposition

AbstractOver the past few decades, remarkable progress has been achieved in terms of understanding the molecular and cellular mechanisms of atherosclerotic vascular calcification and the important role of matrix vesicles in initiating and propagating pathologic tissue mineralization has been widely recognized. Despite these recent advances, however, no definitive data are currently available regarding the texture and composition of the minerals that grow in the vessel wall during the course of the disease. Using different electron microscopy imaging and analysis, we demonstrate that vascular cells can produce and secrete more than one type of matrix vesicles which act as sites for initial mineral deposition independently of their structural features. Our results reveal that apatite formation in the atherosclerotic lesions of the human aorta occur through the deposition of amorphous calcium phosphate that matures over time, transforms into crystalline hydroxyapatite, and radiates towards the lumen of the vesicles, finally forming the calcified spherules. Elemental and mineralogical analyses also demonstrate that the presence of mature and stable amorphous calcium phosphate deposits in the affected tissues is linked to the incorporation of magnesium, which probably delay the conversion to the crystalline phase. Though more rarely, the presence of calcium oxalate crystals has been also documented.

Nanomechanical Properties of Titanium Coated with Octacalcium Phosphate by Immersion in a Simplified Simulated Body Fluid

2008 ◽  
Vol 396-398 ◽  
pp. 365-368
Author(s):  
E. Gemelli ◽  
Christiane Xavier Resende ◽  
Carlos M. Lepienski ◽  
Gloria Dulce de Almeida Soares
Keyword(s):  
Elastic Modulus ◽  
Calcium Phosphate ◽  
Simulated Body Fluid ◽  
Mechanical Behavior ◽  
Amorphous Calcium Phosphate ◽  
Body Fluid ◽  
Octacalcium Phosphate ◽  
Dense Structure ◽  
Nanomechanical Properties

In this study we report on the microstructure and its mechanical behavior of a Ca-P coating produced on bioactive titanium by immersion in a simplified simulated body fluid (S-SBF). The coating was probed by nanoindentation in several point times up to the formation of octacalcium phosphate (OCP). Amorphous calcium phosphate, formed after 1h of immersion in SSBF, presented the highest values of hardness (H) and elastic modulus (E). Nucleation of OCP was observed after 2-2,5h of immersion in S-SBF. From this stage on, lower values of H and E were obtained, probably due to the low dense structure of the coating.

scholarly journals Reversal of Root Caries with Casein Phosphopeptide-Amorphous Calcium Phosphate and Fluoride Varnish in Xerostomia

2021 ◽  
pp. 1-10
Author(s):  
Ahmed Sleibi ◽  
Anwar R. Tappuni ◽  
Aylin Baysan
Keyword(s):  
Calcium Phosphate ◽  
Amorphous Calcium Phosphate ◽  
Primary Root ◽  
Severity Index ◽  
Salivary Flow ◽  
Root Caries ◽  
Carious Lesions ◽  
Group 2 ◽  
Casein Phosphopeptide ◽  
Group 1

Different formulas of topical fluoride have been used to manage root carious lesions. This clinical trial aimed to investigate the efficacy of a dental varnish containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and fluoride compared with fluoride alone in reversing/arresting root caries in xerostomic patients over 1 year. A total of 80 patients (age range 45–92 years) with primary root caries (<i>n</i> = 184 root carious lesions) and unstimulated salivary flow rate of &#x3c;0.2 mL/min were randomly allocated to receive either dental varnish containing CPP-ACP and 5% fluoride (group 1: MI varnish; GC, Japan) (<i>n</i> = 41, 83 lesions), or dental varnish with 5% fluoride alone (group 2: NUPRO White; Dentsply, USA) (<i>n</i> = 39, 101 lesions). Clinical assessments with Severity Index (SI) for root caries, DIAGNOdent measurements, and varnish application were carried out at baseline, 3, 6, and 12 months. Standard oral hygiene instructions with 1,450 ppm fluoride toothpastes were provided for both groups. After 3 months, 63.9% (<i>n</i> = 46) of root caries in group 1 became hard (SI: 0) compared with 39.3% (<i>n</i> = 35) in group 2 (<i>p</i> &#x3c; 0.01). After 6 and 12 months, the differences in SI were insignificant (group 1, <i>n</i> = 60, 83.3%) (group 2, <i>n</i> = 66, 74.2%) (<i>p</i> = 0.36), and (group 1, <i>n</i> = 60, 89.6%) (group 2, <i>n</i> = 67, 81.7%, <i>n</i> = 1 soft, 1.2%) (<i>p</i> = 0.29), respectively. In both groups, noncavitated leathery lesions were more likely to become hard when compared to the cavitated root caries. A significant decrease in plaque index, surface roughness, lesion dimension, and DIAGNOdent readings with a significant increase in lesion distance from the gingival margin was reported in both groups (<i>p</i> &#x3c; 0.05). This study has provided evidence that fluoride dental varnish either with or without calcium and phosphate has the potential to arrest/reverse root caries, especially noncavitated lesions for patients with xerostomia.

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