Osseointegration of composite calcium phosphate bioceramics

Abstract

The resistance of macroporous calcium phosphate ceramics to compressive strength generally is low and depends on, among other factors, porosity percentage and pore size. A compromise always is adopted between high porosity, required for a good integration, and mechanical strength, which increases with material density. We improved the strength of macroporous calcium phosphate ceramics of interconnected porosity by filling the pores with a highly soluble, self-setting calcium phosphate cement made of TCP and DCPD. Cylinders of the resulting material were implanted in sheep condyles and subjected to histological analysis after 20, 60, and 120 days. Microradiographs were made of the histological sections. The control material consisted of ceramic that had not been loaded with cement. Progressive ingrowth of bone into the ceramic pores occurred as the cement was degraded during the first implantation period. Marked degradation of the cement was apparent after 2 months, with fragmentation of the cement in most of the pores and the presence of bone tissue between the fragments. All the cement had been replaced by bone after 4 months. Some fragments of cement still were embedded in the newly formed bone. There was no significant difference between the integration of loaded and nonloaded ceramics. Filling the macroporous ceramic pores with a calcium phosphate cement significantly improved the mechanical strength of these ceramics without modifying their integration in the healing bone.

A review of protein adsorption on bioceramics

“…Since the osteoinductivity and bone regeneration of bioceramics are well-known and proved [28,29], research is further focused on understanding the mechanisms of bioactivity [30 -33]. The works that are in progress mainly cover two aspects.…”

In vivo behavior of three different injectable hydraulic calcium phosphate cements

“…Pronounced new osteoid seams were noticed as early as 3 weeks on CaP particles in rats [20,35] and 8 weeks with CPCs in rabbits [23], while complete resorption took longer than 4 months in most instances [5,21,37]. Depending on the inclusion of a second phase in the brushite matrix, such as calcite or b-tricalcium phosphate granules, only one phase of the cement persisted while the brushite matrix was already completely resorbed [21,27,38] or transformed into apatite [23,28]. Apart from the different components this was also dependent of the site of cement implantation and its vascular situation.…”

3D printing of bone substitute implants using calcium phosphate and bioactive glasses

“…Calcium phosphates are widely used as bone substitute materials. [5][6][7] Especially ␤-tricalcium phosphate (␤-TCP) is known for its good bioresorption properties. [8][9][10] ␤-TCP can react with phosphoric acid as bone cement, forming dicalcium hydrogen phosphate (DCPD) and dicalcium pyrophosphate (DCPP), which are also bioresorbable calcium phosphates.…”