Papers by Keyword: Alpha-Tricalcium Phosphate

Abstract: Silicate-containing alpha-tricalcium phosphate (α-TCP) ceramics are expected to be useful scaffolds for bone regeneration because α-TCP shows high biodegradability and silicate ions are expected to promote the bone formation. We previously revealed that the porous silicate-containing α-TCP granules provided earlier bone formation and showed lower biodegradability than the porous silicate-free α-TCP granules in vivo. In order to reveal the mechanism of the bone formation promoted by silicate incorporation, the proliferation and differentiation of osteoblast-like cells on the silicate-containing and silicate-free α-TCP ceramics were examined in vitro. The silicate incorporation in α-TCP promoted the differentiation of osteoblast-like cells, and it might be one of the factors to promote bone formation In Vivo.

Abstract: The hydration of α−tricalcium phosphate (α−TCP) is known to lead to the formation of an interlinked calcium−deficient hydroxyapatite (CDHA) framework. This apatite resembles the composition and structure of physiologic bone mineral, making it a good candidate for bone reconstruction. The additional presence of a calcium sulfate phase, which has a faster resorption rate than apatite, gives a gradual creation of porosity in the cement. This may in turn enhance bone ingrowth. The aim of this study was to gain deeper understanding of the main characteristics and properties of a bi−phasic α−TCP/α−CSH cement, prepared with an X−ray contrast medium.Isothermal calorimetry has been used to follow the course of the hydration reaction over time as it involves traceable exothermic events with possible contributions from both the calcium phosphate and calcium sulfate components. This was done in an attempt to identify and differentiate the role of each reactive phase. Additionally, the total produced heat from the cement has been used to estimate the degree of conversion and this result has been verified by X−ray diffraction analysis.Furthermore, compressive strength of the α−TCP/α−CSH cement has been measured over time to investigate the possible connection to its thermal evolution signature. Also, the impact of the surrounding environment on the α−TCP and α−CSH conversion was investigated by comparing XRD results between samples that had been kept dry or wet.

Abstract: This study focus on the synthesis of Ca-deficient apatites (CDA) by using the wet chemical precipitation method in demineralised water solutions at pH=7 and synthesis temperature of 90 °C. Upon calcination at 1000°C, the resulting HAP powders decomposed leading to the formation of small amounts of β-TCP. Surprisingly, under some conditions, minor amounts of α- TCP were also formed at 1000°C together with β-TCP. The appearance of α-TCP is favoured by the absence of mineral ions in the precipitation medium, which in turn depends on the purity of the water used. Factors affecting the formation of both β-TCP and α-TCP are discussed.

Abstract: Titanium alloy(Ti-6Al-4V, Samsung techwin, Korea) rods with diameter of 2.5mm were used as the implant materials. Polymethyl methacrylate(PMMA) bone cements(CMW, USA) were used as bone cement and
-tricalcium phosphate(TCP)-based bone filler powder was used as osteoconductive additives. Hydroxyapatite(HA) was the desired end product after hydrolysis of the
-TCP-based bone filler powder mixed with the blood. In animal study using rabbits, we divided the group into A, B, C and D. Rabbits were sacrificed at 1, 3, 9 weeks after implantation and the affinity index and bone density were calculated. X-ray diffraction patterns of HA formed by hydrolysis of
-TCP-based bone filler powder showed higher and higher intensity in HA peak with increase of time period. There was more bone density increase in the group B and D containing
- TCP-based bone filler powder around implant site than in the group A and C(p<0.05). It is suggested that HA formed by hydrolysis of
-TCP-based bone filler powder will play some parts in enhancing osteconducting ability in clinical settings.