Influences of combined supplementation of calcium citrate and calcium carbonate on injectable and anti-washout hydroxyapatite/collagen bone paste utilizing sodium alginate

Influences of combined supplementation of calcium citrate (Ca-Cit) and calcium carbonate (CaCO3) on the hydroxyapatite/collagen (HAp/Col) – sodium alginate (Na-Alg) paste (HAp/Col paste) were investigated. Supplementation amounts of Ca-Cit and CaCO3 were denoted as Nx, where N is a multiplication number to Ca2+ ion amounts for the equivalent reaction with Na-Alg obtained previously. Combined supplementation of 10x Ca-Cit and 2x CaCO3 improved the anti-washout property at a washout ratio of 2.42 ± 0.72 % and pH maintenance at 7.34 ± 0.08, these values were better than the best HAp/Col paste using Ca-Cit (5.91 ± 2.73 % washout ratio and 6.72 ± 0.06 of pH). The HAp/Col paste is expected to be utilized in minimally invasive surgery of bone defects.