Osteoclastic responses to various calcium phosphates in cell cultures

Abstract

Disks made of hydroxyapatite, beta-tricalcium phosphate, carbonate apatite, tetracalcium phosphate, alpha-tricalcium phosphate, dicalcium phosphate dihydrate, and octacalcium phosphate were incubated in osteoclastic cell cultures for 2 days. The first five salts were sintered and the last two were compressed before incubation. Osteoclasts resorbed only the sintered carbonate apatite disks. However, osteoclasts were able to resorb octacalcium phosphate disks that were preincubated for 1 day in medium without cells, indicating that surface conditioning was important for osteoclastic resorption of this calcium phosphate. Although resorption did not occur, medium calcium and phosphorus changed to an appreciable extent after a 2-day incubation of beta-tricalcium phosphate, tetracalcium phosphate, alpha-tricalcium phosphate, and dicalcium phosphate dihydrate. These changes in the medium calcium and phosphate concentrations could explain why osteoclasts appeared to have lost their activity on these calcium phosphate disks and were not capable of resorbing them. With hydroxyapatite disks no changes were observed in the medium calcium and phosphorus before and after incubation. Moreover, the osteoclasts appeared to be essentially the same as with the sintered carbonate apatite disks and with bone slices used as a control. Nevertheless, no pits or lacunae were observed on the hydroxyapatite disks, indicating that sintered carbonate apatite should be superior to sintered hydroxyapatite as a bioresorbable bone substitute.

Fabrication of carbonate apatite block based on internal dissolution-precipitation reaction of dicalcium phosphate and calcium carbonate

“…LeGeros has demonstrated that CO3Ap is easier to dissolve than HAp because the solubility of CO3Ap increased as the content of carbonate in CO3Ap increased 4) under acidic condition such as in the Howship's lacunae of osteoclast 5) . Therefore, CO3Ap is expected to become an ideal bone replacement material, which possesses both osseoconductivity and bioresorbability [6][7][8] .…”

Influence of PLGA concentrations on structural and mechanical properties of carbonate apatite foam

“…Furthermore, osteoclasts have been shown to resorb CO3Ap and then osteoblasts form new bone based on process similar to bone remodeling 4,5) . Introduction of the cells interior to CO3Ap is therefore the key for quick replacement of CO3Ap to bone.…”

Thin carbonate apatite layer biomimetically-coated on SAM-Ti substrate surfaces

“…Carbonate apatite (CA) resembles bone apatite more closely than HA and may prove to be more effective in stimulating bone induction; 8) therefore, it would be ideal to produce CA coatings rather than HA coatings. In the present study, a SAM technique was employed to produce CA coatings on Ti substrates.…”