α-Tricalcium phosphate hydrolysis to octacalcium phosphate: effect of sodium polyacrylate

Bigi, Adriana; Boanini, Elisa; Botter, R.; Panzavolta, Silvia; Rubini, Katia

doi:10.1016/s0142-9612(01)00311-8

Cited by 49 publications

(49 citation statements)

References 18 publications

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“…This effect could be ascribed to the contribution of both the polymers and gelatin: (i) the polymer fibers induce absorption of the liquid phase in the interspaces of the polymer bundles [19], (ii) as a consequence, the amount of liquid available for phase conversion decreases,provoking a slow down of the rate of a-TCP conversion into CDHA, (iii) the prolonged period of time necessary for conversion enhances gelatin inhibiting effect on the growth of the apatitic crystals [5]. In agreement with the X-ray diffraction results, the presence of typical a-TCP particles [24] is still appreciable in the SEM micrographs of the fibers reinforced cements after 7 days soaking in physiological solution (Fig. 6a).…”

Section: Resultssupporting

confidence: 78%

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Fiber reinforcement of a biomimetic bone cement

Panzavolta

Bracci

Focarete

et al. 2012

J Mater Sci: Mater Med

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In this study we investigated the influence of electrospun polymer fibers on the properties of a α-tricalcium phosphate/gelatin biomimetic cement. To this aim, we added different amounts of poly(L-lactic acid) and poly(lactide-co-glycolide) fibers to the cement composition. Fibers enrichment provoked a significant reduction of both initial and final setting times. Moreover electrospun polymer fibers slowed down the conversion of α-tricalcium phosphate into calcium deficient hydroxyapatite. As a result, the final cements were more compact than the control cement, because of the smaller crystal dimensions and reduced crystallinity of the apatitic phase. The compressive strength, σ(b), and Young's modulus, E, of the control cement decreased significantly after 40 days soaking in physiological solution, whereas the more compact microstructure enabled fiber reinforced cements to maintain their mechanical properties in the long term.

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Section: Resultssupporting

confidence: 78%

“…a-TCP was obtained by solid state reaction of a mixture of CaCO 3 and CaHPO 4 Á2H 2 O in the molar ratio of 1:2 at 1300°C for 5 h [24], crushed in a ball mill and sieved (\80 lm).…”

Section: Cement Preparationmentioning

confidence: 99%

Fiber reinforcement of a biomimetic bone cement

Panzavolta

Bracci

Focarete

et al. 2012

J Mater Sci: Mater Med

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“…Figure 7 shows the SEM micrographs of the fractured surface of the cements after 1-week incubation. Needle-like formations, which are thought to be formed by HA generation, 19,20 were observed on all the surfaces. However, fewer were observed on the cement with γ-PGA (Figure 7(c)).…”

Section: Resultsmentioning

confidence: 93%

“…The presence of polyacrylate in cements was reported to inhibit the precipitation of octacalcium phosphate (OCP), which is hydrolyzed to HA; this inhibition is likely due to the competitive interaction of carboxyl ions with calcium ions, which reduces the number of cations available to initiate OCP nucleation. 20 Therefore, the presence of γ-PGA might inhibit the formation of the needle-like structures, whereas PAA did not have this effect because of its small molecular weight. Figure 8 shows XRD patterns of the α-TCP powder and the set cements prepared with liquid components without polyamino acids and with 5 wt% PAA or γ-PGA.…”

Section: Resultsmentioning

confidence: 99%

Preparation and characterization of alpha-tricalcium phosphate cements incorporated with polyamino acids

et al. 2011

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Polymeric calcium phosphate cements (PCPCs) derived from biodegradable polyamino acids, such as polyaspartic acid (PAA) and poly-γ-glutamic acid (γ-PGA), were prepared in an attempt to improve their cohesion strength and injectability. The characteristics of the calcium phosphate cements (CPCs), such as dynamic viscosity, paste injectability, initial setting time, compressive strength and cell compatibility, were assessed. The dynamic viscosity increased significantly with γ-PGA incorporation but decreased with PAA incorporation. The injectability increased with the concentration of polyamino acids and that of the CPCs mixed with γ-PGA reached 94%. The initial setting time decreased with the γ-PGA concentration in the cement liquid and reached approximately 10-15 min when the γ-PGA concentration was 1-2 wt%. The compressive strength (CS) of CPCs after 1 week-incubation decreased with the incorporation of PAA and γ-PGA. γ-PGA incorporation deteriorated the CS more than PAA incorporation because the dissolution of alpha-tricalcium phosphate (α-TCP) was retarded. Saos-2 cells grown on CPCs with polyamino acids spread more than those grown on the CPC without them.

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“…Among calcium phosphates with biodegradable properties 7,12) , we chose to use ␣-TCP, which is converted to octacalcium phosphate (OCP) after hydration 1) , in this study: OCP is a precursor to HAp during the calcification process in vivo 1,4,5) . Conventional non-absorbent HAp particles should be approximately 500m in diameter to gain pores big enough to penetrate newly formed bone or blood vessels 9) .…”

Section: Properties and Structures Of Collagen Sponge And Collagen Plmentioning

confidence: 99%

Effect of New Bone Substitute Materials Consisting of Collagen and Tricalcium Phosphate

Takahashi

2009

Bull. Tokyo Dent. Coll.

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The purpose of this study was to investigate the effect of new bone substitute materials consisting of collagen and tricalcium phosphate (TCP). Prior to the experiment, mandibular dog teeth were extracted. After 3 months, specific cavities were prepared on the alveolar ridge. In one group, cavities were filled with collagen sponge (CS group), in the other, cavities were filled with TCP sponge (TCP group). Cavities with no fillings (Cont group) were created as controls. Mandibular bone was evaluated histopathologically at experimental time periods of 1, 2, 4, and 8 weeks. Due to the non critical inflammatory symptoms that each group showed throughout all the time periods investigated, a low irritation level was observed. Absorption of material was almost complete at after 4 weeks in the CS group, and at after 8 weeks in the TCP group. At the top of the cavity, the TCP group exceeded the Cont group in amount of neogenesis at after 8 weeks. The materials examined in this study showed good osteoconduction and biodegradable character. The TCP Group, in particular, showed highly acceptable results, demonstrating that the materials used were excellent candidates as bone substitute materials.

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α-Tricalcium phosphate hydrolysis to octacalcium phosphate: effect of sodium polyacrylate

Cited by 49 publications

References 18 publications

Fiber reinforcement of a biomimetic bone cement

Fiber reinforcement of a biomimetic bone cement

Preparation and characterization of alpha-tricalcium phosphate cements incorporated with polyamino acids

Effect of New Bone Substitute Materials Consisting of Collagen and Tricalcium Phosphate

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