Korean J Dent Mater.  2021 Dec;48(4):229-244. 10.14815/kjdm.2021.48.4.229.

Evaluation of bone regeneration ability of Mg mesh coated with calcium phosphate by cyclic precalcification treatment

• Park JE
• Kim SY
• Ji JH
• Jang YS
• Jeon WY
• Lee MH
• Bae TS

• KMID: 2524539
• DOI: http://doi.org/10.14815/kjdm.2021.48.4.229

Abstract

Surface treatment was conducted to reduce dissolution of Mg mesh and to improve bioactivity in physiological environment. Mg mesh was immersed in 40 wt% hydrofluoric (HF) solution for 2 hours to form a protective coating layer. Then, hydrothermal treatment was performed in a mixed solution of Ca(NO₃)₂·4H₂O and Na₂HPO 4 at 90 ℃ for 30 minutes, and cyclic precalcification treatment was conducted by soaking in each 0.06 M NH ₄H ₂PO₄ solution and 0.011 M Ca(OH)₂ solution in turn at 90 ℃. Immersion test was performed in simulated body fluid (SBF) to investigate solubility and bioactivity. Release characteristics were investigated after loading ibandronate to suppress initial bone resorption. Bone regeneration ability was evaluated through micro-CT analysis and conforming inflammatory cytokines levels in blood. Fine granular calcium phosphate-based materials were precipitated as clusters on the surface treated in cyclic precalcification. Agglomerated calcium phosphate precipitates on the surface were observed after SBF immersion. pH in SBF during immersion increased slowly in hydrothermal treatment and cyclic precalcification groups compared to pure Mg group. Release of ibandronate occurred over 6 days in cyclic precalcification treatment group (CP-H1). IL-1β and IL-6 were significantly lower than those of untreated group in all test groups except for the group (CP-H4) that was heat-treated at 400 ℃ after pretreatment with circulating calcification. As a result of micro-CT analysis, the new bone volume and density were significantly higher in the CP-H1 group. It was concluded that cyclic precalcification treatment after formation of fluorine protective layer on Mg mesh could retard the dissolution and enhanced bone regeneration ability.

Keyword

Magnesium; Cyclic precalcification; Calcium phosphate; Bone regeneration