The optimum zinc content in set calcium phosphate cement for promoting bone formation in vivo

Abstract

The final aim of our study is to develop a novel calcium phosphate cement based on zinccontaining α-tricalcium phosphate (αZnTCP) and evaluate its potential as bonegraft material in vivo. In the present study, in vivo efficacy of zinc in hardened bodies of αZnTCP was explored. The hardened bodies prepared from αZnTCP with zinc content of 0.00, 0.04, 0.08, 0.11 and 0.19 wt % were prepared by mixing pure αTCP or αZnTCP powder with 12 wt% sodium succinate solution at a solid-to-liquid ratio of 2.0. Due to the release of zinc ions into the physiological salt solution during curing, the zinc content in the hardened bodies was calculated to be 0.00, 0.03, 0.06, 0.10 and 0.18 wt%, respectively. The hardened bodies were implanted in the femora and tibia of white rabbits for 4 weeks. Histological and histomorphometric evaluation showed that the hardened body containing 0.03 wt% zinc, significantly promoted more new bone formation without evoking adverse tissue reactions than that without zinc. The hardened bodies containing 0.06 and 0.10 wt% zinc also resulted in the increase in numbers of active osteoblasts surrounding the new bone but caused inflammation at the implant sites. Results of this study indicate that the hardened body prepared with αZnTCP is superior to that prepared with αTCP in promoting new bone formation due to the release of zinc ions. This study also indicates that the optimum amount of zinc in the hardened body is about 0.03 wt % to avoid inflammatory reaction.

Historical Review of Biological Apatite Crystallography

“…Zinc and/or magnesium containing calcium phosphate [119][120][121][122][123] , and the osteoconductive calcium phosphates [124][125][126][127][128] have been studied and applied to clinical uses.…”

Thin Bioactive Zn Substituted Hydroxyapatite Coating Deposited on Ultrafine-Grained Titanium Substrate: Structure Analysis

“…Cu and Zn ions in small quantities are vital for various metabolic processes in living organisms, while at a higher concentration they could potentially lead to toxic effects. Among those ions, Zn is gaining attention as a not only antibacterial element but as an agent which stimulates bone growth (Li et al, 2009). Since it is of major interest to develop a system that not only prevents pathogenic bacteria colonization but also promotes bone growth, Zn was chosen as a doping element in our case.…”

Improving the bone forming ability of synthetic bone substitutes using trace element additions

“…By incorporating various trace elements into calcium phosphate materials, we expected a release of the doped ion, in this way affecting the cellular responses surrounding the implants and subsequently promote the local osteogenesis. So far the introduction of ions in synthetic materials have been shown to improve their osteoconductivity [122,129,132,135,140,142,148,149,199,[318][319][320], but it is not clear whether osteoinduction may be achieved or whether trace elements may boost the osteoinductivity of the small group of inductive ceramics [42,98,321]. If osteoinduction is obtainable by trace element containing calcium phosphates, it needs to be determined to which extent the inductive bone formation can be attributed to the doped ions.…”

“…silicon [121,122], zinc [123][124][125][126], strontium [122,127,128]) into synthetic bioceramics and improved biological performance was observed both in vitro and in vivo (e.g. silicon [49,121,129], zinc [39,[123][124][125][130][131][132][133][134][135][136][137][138][139][140], strontium [141,122,127,128,131,140,[142][143][144][145][146][147][148][149][150][151][152][153] and fluoride [64,65,67,69,<...>…”

“…Thereafter, zinc has been introduced in various calcium phosphates ceramics in expectation that the release of zinc may promote the bone forming ability of synthetic materials. Naturally it was found that zinc-containing materials would release zinc, and influence the differentiation of osteogenic cells [208] and hence promote the regeneration of nearby host bone [132,135], suggesting their potential role in improving conductive bone formation at osseous site.…”