Article

Kinetics of apatite formation on a calcium-silicate cement for root-end filling during ageing in physiological-like phosphate solutions

Laboratory of Biomaterials and Oral Pathology, Department of Odontostomatological Science, Endodontic Clinical Section, University of Bologna, Italy.
Clinical Oral Investigations (Impact Factor: 2.29). 11/2009; 14(6):659-68. DOI: 10.1007/s00784-009-0356-3
Source: PubMed

ABSTRACT The bioactivity of calcium silicate mineral trioxide aggregate (MTA) cements has been attributed to their ability to produce apatite in presence of phosphate-containing fluids. This study evaluated surface morphology and chemical transformations of an experimental accelerated calcium-silicate cement as a function of soaking time in different phosphate-containing solutions. Cement discs were immersed in Dulbecco's phosphate-buffered saline (DPBS) or Hank's balanced salt solution (HBSS) for different times (1-180 days) and analysed by scanning electron microscopy connected with an energy dispersive X-ray analysis (SEM-EDX) and micro-Raman spectroscopy. SEM-EDX revealed Ca and P peaks after 14 days in DPBS. A thin Ca- and P-rich crystalline coating layer was detected after 60 days. A thicker multilayered coating was observed after 180 days. Micro-Raman disclosed the 965-cm(-1) phosphate band at 7 days only on samples stored in DPBS and later the 590- and 435-cm(-1) phosphate bands. After 60-180 days, a layer approximately 200-900 μm thick formed displaying the bands of carbonated apatite (at 1,077, 965, 590, 435 cm(-1)) and calcite (at 1,088, 713, 280 cm(-1)). On HBSS-soaked, only calcite bands were observed until 90 days, and just after 180 days, a thin apatite-calcite layer appeared. Micro-Raman and SEM-EDX demonstrated the mineralization induction capacity of calcium-silicate cements (MTAs and Portland cements) with the formation of apatite after 7 days in DPBS. Longer time is necessary to observe bioactivity when cements are immersed in HBSS.

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Available from: Maria Giovanna Gandolfi, Aug 16, 2015
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    • "Conventional MTA cements showed some clinical limitation when used as endodontic materials due to their poor handling [24] and extended setting time [9,18–23,25]. The composition of MTA-based cements can be properly modified to improve physicochemical properties as well as handling characteristics, to reduce the setting time [9] [26] [27] and the solubility by including a resin, as previously demonstrated by Gandolfi et al. [28] or the apatite-forming ability [11] [13] [29] [30]. It has been recently demonstrated that MTA cements doped with alpha-tricalcium phosphate support the survival and differentiation of human orofacial bone mesenchymal stem cells [31] and that calcium phosphate have a stimulatory effect on cementoblasts [32]. "
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    ABSTRACT: The aim of this study was to evaluate the calcium release, pH, flow, solubility, water absorption, setting and working time of three experimental root canal sealers based on mineral trioxide aggregate (MTA) and two forms of calcium phosphates (CaP). The materials were composed of a base and a catalyst pastes mixed in a 1:1. The base paste was made by 60% bismuth oxide and 40% butyl ethylene glycol disalicylate. Three different catalyst pastes were formulated containing 60% MTA or 40% MTA+20% CaP (hydroxyapatite HA or dibasic calcium phosphate dehydrate DCPD), 39% Resimpol 8% and 1% titanium dioxide. MTA Fillapex was used as control. The release of calcium and hydroxyl ions, solubility and water absorption were measured on regular intervals for 28 days. The working time and flow were tested according to ISO 6876:2001 and the setting time according to ASTM C266. The data were analyzed using 1-way ANOVA with Tukey's test (p<.01). All the cements showed basifying activity and released calcium ions. MTA Fillapex showed the highest values of flow (p<.01) and working/setting times (p<.01) and the smallest values of solubility (p<.01) and water absorption (p<.01). All experimental materials showed satisfactory physical-chemical properties to be used as endodontic sealers in clinical practice.
    Dental materials: official publication of the Academy of Dental Materials 10/2013; 29. DOI:10.1016/j.dental.2013.10.002 · 4.16 Impact Factor
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    • "http://dx.doi.org/10.1016/j.ceramint.2013.08.064 MTAs and calcium silicate-based cements appear very promising materials due to their well-documented bioactivity [3] [4] [5] [6] [7] [8] [9]. According to the European Society for Biomaterials (ESB) Consensus Conference of 1987 [10], a bioactive material must be able " to induce specific biological activity " . "
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    ABSTRACT: This study was aimed at investigating the effect of the fluoride content (added as NaF) on the in vitro bioactivity of an experimental calcium silicate-based cement (wTC-Bi) obtained from white Portland cement. To this purpose, wTC-Bi and fluoride-doped wTC-Bi cements (i.e. FTC-Bi and F10TC-Bi with fluoride contents of 1% and 10% w/w, respectively) were aged in Dulbecco's Phosphate Buffered Saline (DPBS) and were comparatively analysed by micro-Raman and IR spectroscopy to investigate the presence of deposits on the surface of the cements and the composition changes of the cement as a function of the storage time. Commercial White ProRoot MTA was analyzed as reference. All the tested cements showed the formation of a calcium phosphate deposit already after 5 h of soaking. Fluoride-doped cements demonstrated a higher bioactivity than the undoped wTC-Bi cement. This result was explained in relation to the different solubility of the deposit formed on the cements: a B-type carbonated apatite on the undoped cements and a less soluble fluoride containing B-type carbonated apatite on the fluoride-doped cements. The NaF content was found to influence the apatite forming ability; actually, the cement richer in NaF, i.e. F10TC-Bi showed a lower bioactivity than FTC-Bi, which contained only 1% w/w of NaF. This result may be explained in relation to the lower hydration rate of the former, which showed the formation of lower amounts of CSH, ettringite and portlandite phases.
    Ceramics International 01/2013; 40(3). DOI:10.1016/j.ceramint.2013.08.064 · 2.09 Impact Factor
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    • "In fact, it has been demonstrated that Ca(OH) 2 is effective at reducing the permeability of both smeared (with a smear layer) and acid-etched dentin in vitro [37] [38]. Moreover, calciumsilicate MTA cements trigger the formation of calcium-phosphate crystals [7] [8] [39] [40] inside dentinal tubules, reducing dentin permeability [41]. Both Ca(OH) 2 and MTA act through the combination of a high concentration of ionized calcium and high pH to produce a local aggregation of calcium phosphates. "
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    ABSTRACT: Ca(OH)(2)-containing/forming materials are conventionally used for indirect pulp-capping and are theoretically able to release Ca(2+) and OH(-) ions for hydrolytic dissociation. However, no evidence exists for ion diffusion through the remaining coronal dentin. The aim of this study was to design an innovative experimental set-up to test the ability of Ca(OH)(2)-containing and Ca(OH)(2)-forming pulp-capping materials to generate pulpward Ca(2) and OH(-) ion fluxes through coronal dentin after indirect pulp-capping in vitro. Standardized class 1 cavities were prepared in erupted sound human molars. Pulp tissue was excised. A coronal Remaining Dentin Thickness (RTD) (1±0.2 mm thick) was prepared within an occlusal-to-pulp cavity system (coronal RD system). The whole system/sample was treated with 17% EDTA to remove the smear layer and the external surface was covered by nail varnish. Indirect pulp-capping was performed on coronal RDT using a conventional pulp-capping material covered by a glass ionomer cement, a composite and nail varnish. Chemically different Ca(OH)(2) materials were used to test the reliability of the set-up. The leached Ca(2+) and OH(-) ions were measured using ion-selective electrodes after soaking for 3 hours, 24 hours, and 7 days in deionized water (10 mL, 37°C). Calcium ions were detected and a rise in pH was observed in the treated water after a few hours for all tested materials. The experimental set-up proved to be an easy and effective method for testing the different Ca(OH)(2)-containing and Ca(OH)(2)-forming materials ability to induce a pulpward flux of calcium and hydroxyl ions through coronal remaining dentin after indirect pulp-capping. The new system will allow the screening of current pulp-capping materials.
    10/2012; 7(4):189-97.
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