Effect of silicon level on rate, quality and progression of bone healing within silicate-substituted porous hydroxyapatite scaffolds

Hing, Karin A.; Revell, Peter A.; Smith, Nicola C.; Buckland, Thomas

doi:10.1016/j.biomaterials.2006.05.039

Cited by 338 publications

(284 citation statements)

References 54 publications

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“…On the contrary, the aspects of bone resorption inside the scaffold have so far largely been neglected. Hing et al [25] studied the effect of silicon level in silicate-substituted hydroxyapatite scaffold on bone formation and resorption using histological evaluations. It was observed that bone resorption inside the scaffold started 3 weeks after implantation.…”

Section: Introductionmentioning

confidence: 99%

In vivo loading increases mechanical properties of scaffold by affecting bone formation and bone resorption rates

Roshan-Ghias¹,

Lambers²,

Gholam‐Rezaee³

et al. 2011

Bone

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A successful bone tissue engineering strategy entails producing bone-scaffold constructs with adequate mechanical properties. Apart from the mechanical properties of the scaffold itself, the forming bone inside the scaffold also adds to the strength of the construct. In this study, we investigated the role of in vivo cyclic loading on mechanical properties of a bone scaffold. We implanted PLA/β-TCP scaffolds in the distal femur of six rats, applied external cyclic loading on the right leg, and kept the left leg as a control. We monitored bone formation at 7 time points over 35 weeks using time-lapsed micro-computed tomography (CT) imaging. The images were then used to construct micro-finite element models of bone-scaffold constructs, with which we estimated the stiffness for each sample at all time points. We found that loading increased the stiffness by 60% at 35 weeks. The increase of stiffness was correlated to an increase in bone volume fraction of 18% in the loaded scaffold compared to control scaffold. These changes in volume fraction and related stiffness in the bone scaffold are regulated by two independent processes, bone formation and bone resorption. Using time-lapsed micro-CT imaging and a newly-developed longitudinal image registration technique, we observed that mechanical stimulation increases the bone formation rate during 4-10 weeks, and decreases the bone resorption rate during 9-18 weeks post-operatively. For the first time, we report that in vivo cyclic loading increases mechanical properties of the scaffold by increasing the bone formation rate and decreasing the bone resorption rate.© 2011 Elsevier Inc. All rights reserved. IntroductionThe accepted paradigm in bone tissue engineering is to combine a scaffold with cells and/or growth factors [1][2][3][4][5][6]. The scaffold is used for its osteoconductive properties [7,8] and the cells or growth factors are used for their osteoinductive or osteogenic properties [9,10]. While successful in vivo studies [11,12] and in clinical studies [13], this strategy has difficulties to settle in routine clinical practice. The reasons are manifold but often related to the cost, the stringent regulations established by the regulatory authorities, the specialized infrastructure needed, or the lack of possible reimbursement from health insurances when cells or growth factors are employed.As the use of cells or growth factors is indeed the most difficult element to be included for bone tissue engineering, despite their acknowledged usefulness, we advocate a shift in the bone tissue engineering paradigm. Mechanical loading is an intrinsic stimulation present in the skeleton. It has been demonstrated in numerous in vivo studies to be correlated to bone regulation [14,15]. The in situ mechanical stimulation, if considered in an appropriate way, could then replace the cell and growth factor components of the bone tissue engineering strategy. This new paradigm has been proposed recently [16][17][18]. To support this approach, we have previously shown that controlle...

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Section: Introductionmentioning

confidence: 99%

In vivo loading increases mechanical properties of scaffold by affecting bone formation and bone resorption rates

Roshan-Ghias¹,

Lambers²,

Gholam‐Rezaee³

et al. 2011

Bone

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“…However, from the literature where the study on the growth of human osteoblast cells on the Si-HA deposited substrates with various amounts of Si (0, 0.8, 1.2, and 1.6 wt%) was performed 16 , it was found that the number of such cells increased with the amount of Si during the in vitro culture. On the other hand, a study by Hing et al 17 showed that the Si-HA scaffold with 0.8 wt% Si had the best response for both bone forming and bone resorbing cells, compared to the ones with 0, 0.2, 0.4, and 1.5 wt% Si.…”

Section: Bioactivity Studymentioning

confidence: 96%

Untitled

Seet¹

2009

ScienceAsia

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Hydroxyapatite (HA), the main component of bone and teeth, can improve its structure by incorporation of traces of silicon (Si). This paper reports a synthesis of Si-substituted calcium phosphate compounds via a chemical precipitation process. The solutions of hydroxyapatite and fumed silica were homogeneously mixed before precipitation using ammonia. The resultant solutions were then filtered and the obtained powders were calcined at various temperatures. It was found that the phase of as-precipitated powders was HA with an average size of 15 nm. However, β-tricalcium phosphate (TCP) was formed at the calcined temperature of 800°C. From Fourier-transform infrared spectroscopy spectra, the Si-O peaks were observed when the as-precipitated powder was heated. It was concluded that there was a substitution of silicate ions for phosphate ions in the HA or β-TCP structure. To evaluate the effect of silicon on the bioactivity in vitro, pure HA and silicon-substituted HA (Si-HA) powders were uniaxially pressed and the samples were soaked in simulated body fluid at 37°C for various periods of time. It was found that after 2 weeks of soaking, the surface of the Si-HA sample was covered by apatite layers, whereas that of pure HA remained unchanged even after 4 weeks. These results showed that the presence of silicon can enhance the bioactivity of HA.

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“…Si substitution in sHAs also increases the dissolution of Ca and P during early stages of healing, which is an important precondition for bone formation ( [56,66]; see below). In vivo experiments in the rabbit revealed advanced bone formation [67]. Therefore, Sibased CaP grafts have already been considered as a sort of drug delivery device by releasing Si in vivo and influencing cell activity during osteogenesis [41].…”

Section: Characterization and Preparation Of Synthetic Hamentioning

confidence: 99%

“…An in vitro study in protein expression profiles of osteoblasts cultured on HA nanoparticles showed an upregulation of the osteogenic genes ALP and OC, and the regulation of several genes involved in Ca metabolism [74]. Investigations in the rabbit revealed a very early bone ingrowth of Si substituted porous HA implants in contrast to stoichiometric HA by using a Si level of 0.8wt% [67]. It can be concluded from in vitro and in vivo studies, that Si mainly influences early events of bone regeneration by HA scaffolds.…”

Section: Characterization and Preparation Of Synthetic Hamentioning

confidence: 99%

Molecular, Cellular and Pharmaceutical Aspects of Synthetic Hydroxyapatite Bone Substitutes for Oral and Maxillofacial Grafting

Götz¹,

Papageorgiou²

2017

CPB

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Bone grafts are widely used for augmentation procedures in oral and maxillofacial surgery, with autogenous bone being the gold standard. Recently, the focus of research has shifted towards synthetic bone substitutes, as no second surgery is needed and large quantities of graft can easily be provided. Within the broad range of bone substitutes, synthetic hydroxyapatite has drawn much attention, as they are considered to be biocompatible, non-immunogenic, osteoconductive and osteoinductive. Scope of this review is to summarize existing knowledge concerning the molecular, cellular and pharmaceutical aspects of synthetic bone substitutes for oral and maxillofacial grafting.

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Effect of silicon level on rate, quality and progression of bone healing within silicate-substituted porous hydroxyapatite scaffolds

Cited by 338 publications

References 54 publications

In vivo loading increases mechanical properties of scaffold by affecting bone formation and bone resorption rates

In vivo loading increases mechanical properties of scaffold by affecting bone formation and bone resorption rates

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Molecular, Cellular and Pharmaceutical Aspects of Synthetic Hydroxyapatite Bone Substitutes for Oral and Maxillofacial Grafting

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