Tricalcium phosphate p-TCP

Other Ceramic Calcium Phosphate Materials. Other ceramic calcium phosphate materials for repairing bony defect iaclude p-tricalcium phosphate (P-TCP) [7758-87-4], P-Ca2(PO, and biphasic calcium phosphate (BCP) ceramics which consist of both P-TCP and HA. Unlike ceramic HA, P-TCP resorbs ia the tissue (293). The in vivo dissolution of BCP ceramic implants was shown (296) to iacrease with increasing P-TCP/HA ratio ia the implants. Both P-TCP and BCP can lead to new bone growth to various extents depending on the appHcations and the type of materials used (293,296). 

Figure 7.9 Raman standard spectra of tetracal-cium phosphate (TTCP, (a)), p-tricalcium phosphate (P-TCP, (b)) and hydroxyapatite (HAp, (c)).

Thermal stability is characterized by the decomposition temperature of HAp sample. The decomposition occurs when a critical dehydration point is achieved. In the temperatures less than the critical point, crystal structure of HAp remains unchanged in spite of the stage of dehydration. Achieving the critical point, a complete and irreversible dehydroxillation occurs, which results damage of HAp structure, decomposing onto tricalcium phosphate (P-TCP under 1200 °C and a-TCP in higher temperatures) and tetracalcium phosphate (TTCP). 

C Transformation of Hydroxyapatite into beta-Tricalcium Phosphate [p-TCP]... 

Two polymorphous forms of tricalcium phosphates (TCPs) are beta-tricalcium phosphate (P-TCP) and alpha-tricalcium phosphate (a-TCP). a-TCP is stable between 1120°C and 1470°C and P-TCP is stable below 1120°C (Mathew and Takagi 2001). 

P-Tricalcium phosphate (P-TCP), is a calcium-phosphate bioactive ceramic with excellent degradation properties[91]. Incorporation of [)-TCP in siUcone rubber led to a material that fulfills the mechanical and biological requirements... 

HA has been used, both in soluble and crosslinked forms, as a carrier for calcium phosphate particles to stimulate bone regeneration. In a subcutaneous implantation model, an injectable paste-like material, consisting of beta-tricalcium phosphate (P-TCP), methylcellulose, and HA, increased the half-life of the P-TCP particles and ultimately vascularisation of the implantation bed [99]. In a unilateral tibial defect model in rabbits, the same formulation promoted a significant increase in new bone volume fraction after one week however, by 4 weeks, there was no difference in bone formation compared to controls [100]. Similarly, medical grade HA of three different MW (900,000 - Artz 1,900,000 - Suvenyl and 6,000,000 - Synvisc) were evaluated as carriers for octacalcium phosphate granules in a mouse subperiosteal calvarial model [101]. The formulations with... 

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