title: Effects of calcium phosphate nanoparticles on Ca-PO4 composite.
abstract: Nano-particles of dicalcium phosphate anhydrous (DCPA) were synthesized for the first time. The objectives of this study were to incorporate DCPA nano-particles into resin for Ca-PO(4) release to combat dental caries, and to investigate the filler level effects. Nano-DCPA and nano-silica-fused silicon nitride whiskers at a 1:1 ratio were used at filler mass fractions of 0-75%. The flexural strengths in MPa (mean +/- SD; n = 6) of DCPA-whisker composites ranged from (106 +/- 39) at 0% fillers to (114 +/- 23) at 75% fillers, similar to (112 +/- 22) of a non-releasing composite (TPH) (p > 0.1). The composite with 75% fillers in a NaCl solution (133 mmol/L, pH = 7.4, 37 degrees C) yielded a Ca concentration of (0.65 +/- 0.02) mmol/L and PO(4) of (2.29 +/- 0.07) mmol/L. Relationships were established between ion-release and DCPA volume fraction V(DCPA): Ca = 4.46 V(DCPA)(1.6,) and = 66.9 V(DCPA)(2.6). Nano-DCPA-whisker PO(4) composites had high strength and released high levels of Ca-PO(4) requisite for remineralization. These new nano-composites could provide the needed combination of stress-bearing and caries-inhibiting capabilities.
authors: Paffenbarger Research Center, American Dental Association Foundation, National Institute of Standards and Technology, Building 224, Room A-153, Stop 8546, Gaithersburg, MD 20899-8546, USA. hockin.xu@nist.gov
authors: H H K
authors: HH
authors: Xu
authors: M D
authors: MD
authors: Weir
authors: L
authors: L
authors: Sun
authors: S
authors: S
authors: Takagi
authors: L C
authors: LC
authors: Chow
mesh_terms: D000704:Analysis of Variance; D002118:Calcium / Q000008:administration & dosage; D002130:Calcium Phosphates / Q000737:chemistry*; D002327:Cariostatic Agents / Q000008:administration & dosage* / Q000737:chemistry; D003188:Composite Resins; D003764:Dental Materials / Q000737:chemistry*; D003799:Dental Stress Analysis; D004548:Elasticity; D006244:Hardness; D007477:Ions; D008422:Materials Testing; D053761:Nanocomposites / Q000737:chemistry*; D010710:Phosphates / Q000008:administration & dosage; D018583:Pliability; D017655:Silicon Compounds; D014089:Tooth Remineralization / Q000379:methods*
chemical_list: D002130:Calcium Phosphates; D002327:Cariostatic Agents; D003188:Composite Resins; D003764:Dental Materials; D007477:Ions; D010710:Phosphates; D017655:Silicon Compounds; C113300:TPH hybrid; C485829:calcium phosphate, dibasic, anhydrous; C032734:silicon nitride; D002118:Calcium