Friday 10 June 2011

SMART COMPOSITES (calcium and phosphate containing composites)


    Calcium and phosphate particles have been used as fillers in dental resins, and the resulting composite released calcium (Ca) and phosphate (P04) ions, which can form hydroxyapatite. However, the Ca—P04 composites had less flexural strengths. Such low strengths were insufficient to make these composites acceptable as bulk restoratives. Recently, nanoparticles of calcium phosphates were synthesized and incorporated into dental resins. The high surface area of the nanoparticles, along with  fillers, resulted in composites with stress-bearing and Ca and P04 releasing capabilities. Tetracalcium phosphate is another important compound used in bone cements, tissue engineering scaffolds, and dental composites. TTCP is the most alkaline among all Ca—P04 compound and, hence, is promising in buffering harmful acids and inhibiting tooth caries.

 pH of around  5.5—4 is considered to be cariogenic . Therefore, it is desirable for Ca—P04 composite to be “smart”, to increase the release of caries-inhibiting ions when ph drops.

 example : ariston phc 

                                 REF :  DENTAL MATERIALS 25 (2009) 535—542                                              

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