Early Differentiation and Attachment of Osteoblasts to Different Surface Roughness of Dental Pure Titanium Implant

Kim, Byung Soo; Kim, Hyun Jin; Kim, Sun Hun

Abstract

Early bone formation and close contact between dental implant and tissue bed are important for successful osseointegrated dental implants. Surface characteristics of implant materials such as roughness and topography have effects on peri-implant tissue reaction in addition to chemical properties of dental implants. The specific reactions of osteoblasts or their lineages to implant surface accompany changes of their phenotype. This study was undertaken to unravel cell differentiation and functional changes, responding to different implant surfaces characteristics. Cell proliferation, scanning electron microscopy and RT-PCR analyses for COX-2, ERK-1, ERK-2, Type I collagen, beta-catenin, PLC-gamma2, beta-actin were carried using MG 63 preosteoblastic cells at 18 hours and 5 days of culture in vitro. The number of attached cells on rough surface titanium (Ra=2.93+/-0.21 micrometer) was less than that on smooth surface titanium (Ra=0.24+/-0.04 micrometer) at both 18 hours and 5 days of culture (p<0.01). Cells on smooth surface titanium were flat and spindle-shaped and their margin was smooth. In contrast, cells on rough surface titanium seemed to be thicker and shaped following pits and projections of the surface and their margin was irregular with many processes. At 18 hours of culture, erk2 mRNA expression in rough surface titanium was more than that in smooth. Similarly at 5 days of culture, erk1 and collagen I transcriptions were more than those of smooth surface titanium (p<0.01 and p<0.05 respectively). These results suggest that rough surface titanium directs preosteoblasts toward differentiation rather than proliferation, comparing smooth surface titanium, and genes such as erk1 and erk2 would be involved in the cellular changes.