チタンへの超親水処理後の水中保存が骨芽細胞の動態に及ぼす影響

抄録

It has been found that the super-hydrophilicity of implant surfaces plays an important role for the initial attachment and subsequent behavior of cells. Super-hydrophilicity has been obtained by physical treatment (atmospheric-pressure plasma and UV treatment) as well as chemical treatment (blasting and acid-etching). However, the super-hydrophilicity rapidly decreases over time in air atmosphere. If the super-hydrophilicity after physical treatment can be sustained during long-term storage in water and osteogenesis on these super-hydrophilic surfaces is confirmed, this treatment is expected to be a promising method for clinical application as the disadvantage of chairside treatment is reduced. The present study evaluated the initial attachment, proliferation and differentiation of osteoblast-like cells on titanium surfaces that were stored in distilled water after various superhydrophilic treatments, and discussed the efficacy of long-term storage in water after super-hydrophilic treatment.

Commercially pure titanium discs were subjected to blasting and acid-etching, and the following treatments were performed : 1) stored in air atmosphere (As-Air) , 2) stored in distilled water (As-DW), 3) stored in distilled water after atmospheric-pressure plasma treatment of As-Air specimens (Plasma-DW) , and 4) stored in distilled water after UV treatment of As-Air specimens (UV-DW). The storage period was 1 month in all conditions. Surface morphology, wettability, and surface energy of these specimens were evaluated. Furthermore, mouse osteoblast-like cells MC3T3-E1 were cultured on these specimens, and then initial cell attachment, proliferation, alkaline phosphatase activity, and secretion of calcospherite were evaluated.

Though the As-Air specimens showed hydrophobicity, the As-DW, Plasma-DW and UV-DW specimens that were stored in distilled water showed super-hydrophilicity. Surface energy increased on all super-hydrophilic groups compared to the hydrophobic specimens. Initial cell attachment, proliferation, and alkaline phosphatase activity were enhanced more on super-hydrophilic groups than on the As-Air specimens. These properties showed no apparent differences in the super-hydrophilic groups. Secretion of calcospherite and collagen was confirmed on all specimens.

These results indicate that the storage in distilled water after physical treatment (atmospheric-pressure plasma and UV treatment) as well as chemical treatment (blasting and acid-etching) sustained the super-hydrophilicity, and enhanced the initial attachment, proliferation, and differentiation of osteoblast-like cells compared to specimens stored in air atmosphere, indicating that the method is promising for clinical application.