Effects of calcium phosphate nanoparticles on Ca-PO4 composite

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-PO4 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 PO4 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 PO4 = 66.9 V-DCPA(2.6). Nano-DCPA-whisker composites had high strength and released high levels of Ca-PO4 requisite for remineralization. These new nano-composites could provide the needed combination of stress-bearing and caries-inhibiting capabilities.