티타늄 표면처리방법이 전조골세포의 반응에 미치는 영향

Abstract

Surface roughness has been shown to be an important factor in the successful osteointegration of titanium implants. At the implant-bone interface, implant surface roughness modulates osteoblast response. In this study, 4 kinds of titanium(Ti-6Al-4V) discs with different surface treatments were examined. 1) SA70 ; sandblasted with 70 ㎛ Al₂O₃particles and acid-etched(with 38% HCL), 2) SA150 ; sandblasted with 150 ㎛ Al₂O₃particles and acid-etched, 3) SA300 ; sandblasted with 300 ㎛ Al₂O₃particles and acid-etched, 4) SAmix ; sandblasted with mixed-sized Al₂O₃particles and acid-etched(3 sizes of particles were mixed with the same proportion). Mouse pre-osteoblasts(MC3T3-E1 cells) were cultured on these titanium discs for 24 and 48 hours. Cell morphology was analyzed by SEM(S-4300, Hitachi, Japan) and cell proliferation was measured by MTT assay. mRNA expression of osteonectin, Runx2 and bone sialoprotein(BSP) were analyzed by RT-PCR technique. Ra values were 0.68±0.02 ㎛ (SA70), 1.04±0.01 ㎛ (SA150), 1.79±0.12 ㎛(SA300) and 1.16±0.11 ㎛ (SAmix), respectively. In SEM, pre-osteoblasts did spread well on all titanium surfaces. Morphology of pre-osteobalsts differed on surface roughness. Pre-osteoblasts cultured on SA70 were thin, flat and covered the surface. Pre-osteoblasts cultured on SA150, SA300 and SAmix showed elongated shapes with irregular extended processes. In MTT assay, cell proliferation was increased in pre-osteoblasts cultured on SA70 than SA150, SA300. In RT-PCR analysis, mRNA expression of Osteonectin and Runx2 was increased in pre-osteoblasts cultured on SA150, SA300 than SA70. It was highest in pre-osteoblasts cultured on SA300. SAmix was higher than SA70 and lower than SA150, SA300. These results indicate that titanium surface roughness affects pre-osteoblast morphology, proliferation and gene expression, and that SA300 (Ra:1.79±0.12㎛) seems to be the most favorable surface inducing increased expression of bone specific protein such as osteonectin and Runx2. Further studies are needed to determine the effect of sand-blasting with mixed-sized particles.