In vivo stability evaluation of Mg substituted low crystallinity ß-tricalcium phosphate granules fabricated through dissolution–precipitation reaction for bone regeneration

Abstract

Although β-tricalcium phosphate (β-TCP) is widely used in clinical applications as a bone substitute owing to its positive tissue response and its ability to be replaced by new bone through a bone-remodeling process, it has the limitation of rapid resorption in vivo, which might become a reason for tissue atrophy and high crystallinity, which decrease biocompatibility. A reduction in the crystallinity might increase the biocompatibility of the bone substitute. To overcome the drawbacks of β-TCP, decrease in crystallinity and solubility, both are required. Therefore, in this study, the feasibility of fabricating Mg substituted low crystalline β-TCP (Mg-LC-β-TCP) granules formed in aqueous solution was evaluated in vivo focusing long-term adsorption and bone formation in bone defects formed in the rabbit femur using sintered β-TCP granules as a control. With Mg-LC-β-TCP, the resorption of the substitute was suppressed, and no tissue atrophy was observed even at 24 weeks post-implantation, whereas a few granules with surrounding tissue atrophy were observed at 12 weeks post-implantation. Tartrate-resistant acid phosphatase-staining indicated that the density of osteoclasts type cells with Mg-LC-β-TCP was significantly lower than that with β-TCP, and also the numbers of osteoblasts type cells with Mg-LC-β-TCP were significantly higher than that with β-TCP. It is suggested that Mg substitution to form low crystallinity β-TCP is a valuable way to overcome the limitations of β-TCP as a bone substitute.

Apatitic calcium phosphate/montmorillonite nano-biocomposite: in-situ synthesis, characterization and dissolution properties

“…For both samples AP-2MNa and AP-5MNa with HAP structure, the concentration of Ca A decrease in dissolution may be due to the presence of agglomerates. On the other hand, it was reported that the dissolution rate of β-TCP decreased with incorporation of ions as Mg 2þ [49,50]. In our work, the simultaneous cationic and anionic incorporation of clay ions (e.g.…”

“…On the other hand, it was reported that the dissolution rate of β-TCP decreased with incorporation of ions as Mg 2+ [ 49 , 50 ]. In our work, the simultaneous cationic and anionic incorporation of clay ions (e.g.…”

Strategies for advanced particulate bone substitutes regulating the osteo-immune microenvironment

“…Lourenço et al [120] designed a Sr-hybrid system which has been demonstrated to stimulate the polarisation of M2-like macrophages and osteogenic differentiation of MSCs. Less atrophy of ceramics and more osteoblasts was observed even 24 weeks after implantation of Mg substituted low crystalline β-TCP granules [121]. Bose et al [122] showed that Mg-Si doped TCP exerts a positive effect on both osteogenesis and angiogenesis.…”

The effect of the incorporation of Mg in beta tricalcium phosphate: a brief review

“…Theoretical calculations indicate that the decrease in unit cell volume due to magnesium replacements leads to a slight decrease in the rate of Mg-β-TCP coating deposition. The relationship between the unit cell volume of the sprayed powder and its deposition rate is revealed, with larger unit cell volumes generating higher spray rates Tripathi et al (2018). focused on in vivo Mg-LC-β-TCP responses during long-term implantation with a focus on osteoblast-and osteoclast-like cell responses using an immunity staining method.…”