Bone bonding mechanism of β‐tricalcium phosphate

Abstract

It has been proposed that the formation of a surface apatite layer in vivo on surface active ceramics is an essential condition for chemical bonding between ceramics and bone tissue. To clarify the difference in bone-bonding mechanisms between surface active ceramics and bioresorbable ceramics, two experiments were performed using plates of dense beta-tricalcium phosphate (beta-TCP). First, plates of beta-TCP were implanted subcutaneously in rats for 8 weeks. Surface change due to bioresorption was observed with scanning electron microscopy. Formation of the apatite layer on the surface was investigated using thin-film x-ray diffraction and Fourier transform infrared reflection spectroscopy. Second, plates of beta-TCP were implanted in tibiae of rabbits for 8 and 25 weeks and subjected to the detaching test to measure bone-bonding strength. beta-TCP bonded strongly to bone. Undecalcified sections of the interface of bone and beta-TCP were examined with SEM-EPMA. However, by physicochemical methods, no formation of surface apatite layer was observed. These results suggest that beta-TCP bonds to bone through microanchoring between bone and rough surface of resorbed beta-TCP.

Bioglass and bioceramic composites processed by Spark Plasma Sintering (SPS): biological evaluation Versus SBF test

“…In this context the present contribution aims not only to test the biocompatibility towards cells of bioceramic samples obtained by SPS, which is a technique that only recently has been employed for the production of bioglass and HA/bioglass composites, but also to further demonstrate that SBF assays should be considered as preliminary screening tests, since SBF is not able to mimic the complexity of a real physiological environment, which contains cells, proteins, specific trace elements, etc [39]. Cytotoxicity tests, based on in vitro cell culture assays, are crucial in order to confirm the findings from the bioactivity evaluation with SBF, which has been reported in the literature to lead both to false negative and false positive results [40][41][42]. In this context, probably the most striking case is that of β-Tricalcium Phosphate: despite its high bone-bonding ability in vivo, it does not always induce the formation of hydroxyapatite in SBF [39].…”

Enhancement of Bone-Like Apatite Forming Abilities of Calcium Phosphate Ceramics in SBF by Autoclaving

“…13 Neo and Kotani et al showed that b-TCP directly bonded to bone intervening no apatite layer by in vivo tests. 4,14,15 On the other hand, Daculsi et al reported formation of carbonate apatite layer in the vicinity of implanted b-TCP. 16 However, connectivity of b-TCP with host bone was reported to be strong in general and attributed to rough surface due to degradation of implanted b-TCP.…”

Ensuring defined porosity and pore size using ammonium hydrogen carbonate as porosification agent for calcium phosphate scaffolds

“…Furthermore, the volume percentage of the total porosity should be higher than 60% [7]. Besides the requirement for a specific macroporosity of the ceramic scaffold, a certain percentage of microporosity is important for osteogenesis and the anchoring of the implant to sur rounding bone tissue [14]. Therefore, several techniques were developed to integrate the desired porous structure into calcium phosphate scaffolds [15][16][17][18][19][20][21][22][23][24][25][26].…”