HA/TCP compounding of a porous CaP biomaterial improves bone formation and scaffold degradation—A long‐term histological study

Abstract

In the present study, two biphasic calcium phosphate biomaterials (BCP) with HA/TCP ratios of 50/50 and 30/70 were obtained from a pure HA biomaterial. The biomaterials which showed the same three-dimensional geometry were implanted into corticocancellous costal defects of sheep. In the specimens of all three biomaterials, abundant bone formation, mineral dissolution from the biomaterial scaffolds, and active cellular resorption of the scaffolds was present after 6 and 12 months. Backscattered electron microscopy showed bone invasion into the pores of the scaffolds and micromechanical interlocking at the bone/biomaterial interface without intervening soft tissue. The pattern of bone formation and scaffold resorption was different for cortical and cancellous bone. No time-based effect, however, was observed. Overall, the BCP biomaterials had formed significantly more bone than the HA biomaterial. Also, scaffold resorption, which was followed by a replacement with newly formed bone, was significantly higher in the BCP biomaterials. Although no significant differences were observed between both BCP biomaterials, the present study had confirmed the assumption that HA/TCP compounding was suitable to improve bone formation and scaffold resorption in the investigated biomaterials and at the same time maintain the osteoconductive properties of the scaffolds.

Designs from the deep: Marine organisms for bone tissue engineering

“…In an attempt to increase the resorption rate, biphasic CaP materials were produced from the algal template, with various ratios of HA to  tricalcium phosphate (TCP) (Spassova et al, 2007). In a cortico-cancellous defect model in sheep, biphasic materials with HA:TCP ratios of 50:50 and 30:70 did show a statistically significant decrease in residual graft volume and an increase in bone volume after 6 months compared to 100% HA but there was no further reduction in the material volume of any of the materials at 12 months and considerable amounts of even the 30:70 graft remained (Schopper et al, 2005).…”

In vitro effects of particulate bone substitute materials on the resorption activity of human osteoclasts

“…Such compound materials, called biphasic bone substitute materials, are available in order to control the velocity of biodegradation by adapting the β-TCP to HA ratio (Chow, 2009;Schopper et al, 2005;Sheikh et al, 2015).…”

“…If such calcium phosphates feature high crystallinity, they show considerably lower solubility than so-called amorphous calcium phosphates (at 25 °C, −log (Ks) ≈ 25) (Dorozhkin, 2011). (Accorsi-Mendonca et al, 2008;Dorozhkin, 2011;Ewers, 2005;Schopper et al, 2003;Schopper et al, 2005;Spassova, 2007;Tadic and Epple, 2004). The phase composition ratio was estimated from X-ray diffraction powder patterns (CuKα radiation) using the Rietveld method.…”

Augmentation and Preservation of the Alveolar Process and Alveolar Ridge of Bone

“…HA/TCP offers an interconnected porosity of 90% (pores ranging from 100-500 µm in diameter) to support cellular penetration. While the HA -biphasic TCP compound have shown promising results extraorally (Russotti et al 1987;Brook et al 1991;St John et al 1993;Emery et al 1996;Gauthier et al 2001;Le Nihouannen et al 2005;Schopper et al 2005;Blouin et al 2006;Fellah et al 2006) and in animal studies also intra-orally (Hashimoto-Uoshima et al 1995;Boix et al 2004Boix et al , 2006, it still lacks clinical validation in intra-oral applications in humans.…”