OBJECTIVETo investigate the effect of nanometer hydroxyapatite on the proliferation and the osteogenetic differentiation of periodontal ligament cells (PDLC).

METHODSNano-hydroxyapatite powders were fabricated with sol-gel method. The fourth passage periodontal ligament cells were cultured with nanometer hydroxyapatite powder (nano-HA), dense hydroxyapatite powder (dense-HA) and only medium as control respectively. On the 5th, 8th day of culture, the osteogenetic differentiation of human periodontal ligament cells was evaluated though alkaline phosphatase (ALP) activity, ALP immunohistochemical stain and ALP positive flow cytometry.

RESULTSThere were significant differences among nano-HA group, dense-HA group and control group on the 5th and 8th day of culture. A majority of nano-HA group and dense-HA group cells sample showed positive ALP stain. But the ALP positive stain of nano-HA group cells sample was denser than that of dense-HA group. In FCM, the distribution of ALP positive cells cultured with nanoparticles were significantly more than that of other groups.

CONCLUSIONSThe nano-HA, as a calcium phosphate biomaterial, has ability to promote the activity of osteogenetic differentiation for periodontal ligament cells compared with dense-HA.