Stoichiometry of hydroxyapatite: influence on the flexural strength

Royer, Alexandre; Viguié, Jérémie; Heughebaert, M.; Heughebaert, J.-C.

doi:10.1007/bf00122982

Cited by 94 publications

(71 citation statements)

References 16 publications

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“…The fact that decomposition of HA phase was not observed in the present material even for the high temperature (i.e. 1200 1C) sintered samples is not in agreement with the findings of Royer et al [21] and Wang et al [22] who reported that decomposition of HA starts at about 1300 1C, accompanied by deterioration of mechanical properties of HA ceramics. In general, sintering of HA can lead to the partial thermal decomposition of HA into TCP and/or TTCP [23].…”

Section: Resultscontrasting

confidence: 89%

Consolidation of nanocrystalline hydroxyapatite powder

Ramesh

Tan

Sopyan

et al. 2007

Science and Technology of Advanced Materials

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The effect of sintering temperature on the sinterability of synthesized nanocrystalline hydroxyapatite (HA) was investigated. The starting powder was synthesized via a novel wet chemical route. HA green compacts were prepared and sintered in atmospheric condition at various temperatures ranging from 900-1300 1C. The results revealed that the thermal stability of HA phase was not disrupted throughout the sintering regime employed. In general, the results showed that above 98% of theoretical density coupled with hardness of 7.21 GPa, fracture toughness of 1.17 MPa m 1/2 and Young's modulus of above 110 GPa were obtained for HA sintered at temperature as low as 1050 1C. Although the Young's modulus increased with increasing bulk density, the hardness and fracture toughness of the sintered material started to decline when the temperature was increased beyond 1000-1050 1C despite exhibiting high densities 498% of theoretical value. The occurrence of this phenomenon is believed to be associated with a thermal-activated grain growth process. r

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Section: Resultscontrasting

confidence: 89%

Consolidation of nanocrystalline hydroxyapatite powder

Ramesh

Tan

Sopyan

et al. 2007

Science and Technology of Advanced Materials

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“…The high-temperature stability of the HA phases, particularly for samples sintered at 1400 1C, is not in agreement with the findings of Royer et al [33] and Wang et al [34]. Both these authors reported that decomposition of HA started at about 1300 1C.…”

Section: Discussioncontrasting

confidence: 48%

The effect of manganese oxide on the sinterability of hydroxyapatite

Ramesh

Tan

Peralta

et al. 2007

Science and Technology of Advanced Materials

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The sinterability of manganese oxide (MnO 2 ) doped hydroxyapatite (HA) ranging from 0.05 to 1 wt% was investigated. Green samples were prepared and sintered in air at temperatures ranging from 1000 to 1400 1C. Sintered bodies were characterized to determine the phase stability, grain size, bulk density, hardness, fracture toughness and Young's modulus. XRD analysis revealed that the HA phase stability was not disrupted throughout the sintering regime employed. In general, samples containing less than 0.5 wt% MnO 2 and when sintered at lower temperatures exhibited higher mechanical properties than the undoped HA. The study revealed that all the MnO 2 -doped HA achieved 499% relative density when sintered at 1100-1250 1C as compared to the undoped HA which could only attained highest value of 98.9% at 1150 1C. The addition of 0.05 wt% MnO 2 was found to be most beneficial as the samples exhibited the highest hardness of 7.58 GPa and fracture toughness of 1.65 MPam 1/2 as compared to 5.72 GPa and 1.22 MPam 1/2 for the undoped HA when sintered at 1000 1C. Additionally, it was found that the MnO 2 -doped samples attained E values above 110 GPa when sintered at temperature as low as 1000 1C if compared to 1050 1C for the undoped HA. r

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“…122 On the basis of the composition and stoichiometry of a calcium-phosphate ceramic, important physical properties such as degradation rate, modulus, and processability can be changed. [123][124][125][126] Research on TCP materials has revealed that the degradation rate is too rapid in vivo, while synthetic versions of HAp degrade too slowly to allow native tissue integration. This phenomenon motivated the development of BCP and bio-glasses which have tunable (to some degree) degradation rates based on the relative magnitude of TCP (more commonly b-TCP) and HAp in a composite ceramic.…”

Section: Bone Biomimeticsmentioning

confidence: 99%

Bone tissue engineering: A review in bone biomimetics and drug delivery strategies

Porter

Ruckh

Popat

2009

Biotechnology Progress

685

499

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Critical‐sized defects in bone, whether induced by primary tumor resection, trauma, or selective surgery have in many cases presented insurmountable challenges to the current gold standard treatment for bone repair. The primary purpose of a tissue‐engineered scaffold is to use engineering principles to incite and promote the natural healing process of bone which does not occur in critical‐sized defects. A synthetic bone scaffold must be biocompatible, biodegradable to allow native tissue integration, and mimic the multidimensional hierarchical structure of native bone. In addition to being physically and chemically biomimetic, an ideal scaffold is capable of eluting bioactive molecules (e.g., BMPs, TGF‐βs, etc., to accelerate extracellular matrix production and tissue integration) or drugs (e.g., antibiotics, cisplatin, etc., to prevent undesired biological response such as sepsis or cancer recurrence) in a temporally and spatially controlled manner. Various biomaterials including ceramics, metals, polymers, and composites have been investigated for their potential as bone scaffold materials. However, due to their tunable physiochemical properties, biocompatibility, and controllable biodegradability, polymers have emerged as the principal material in bone tissue engineering. This article briefly reviews the physiological and anatomical characteristics of native bone, describes key technologies in mimicking the physical and chemical environment of bone using synthetic materials, and provides an overview of local drug delivery as it pertains to bone tissue engineering is included. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009

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Stoichiometry of hydroxyapatite: influence on the flexural strength

Cited by 94 publications

References 16 publications

Consolidation of nanocrystalline hydroxyapatite powder

Consolidation of nanocrystalline hydroxyapatite powder

The effect of manganese oxide on the sinterability of hydroxyapatite

Bone tissue engineering: A review in bone biomimetics and drug delivery strategies

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