OBJECTIVETo determine whether the roughness of titanium implant can influence its osseointegration by affecting the growth, alkaline phosphatase (ALP) production and expression of core binding factor alpha 1 subunit (Cbfα1) of osteoblasts.

METHODSTotally 48 titanium disc specimens, 15 mm in diameter and 2 mm in thickness, were included in the study and divided equally into 4 groups with 12 specimens in each group. Specimens were coarsened by sandblasting with carborundum granula and acid etching with mixing liquid of hydrochloric acid and sulphuric acid under diverse conditions. In the four groups, three were treated with different surface roughness: micro-roughness [(1.00 ± 0.20) µm], midrange roughness [(1.67 ± 0.08) µm] and severe roughness [(2.40 ± 0.20) µm], while the group untreated with surface roughness [(0.12 ± 0.03) µm] was set as control. Scanning electron microscope, acridine orange fluorescence staining and coomassie brilliant blue staining were used to observe morphology and growth of osteoblasts incubating on these specimens. Enzyme linked immunosorbent assay (ELISA) and fluorescence quantitative real-time polymerase chain reaction were used to evaluate ALP production and gene expression of Cbfα1 of osteoblasts among different groups.

RESULTSGrowth, ALP production and Cbfα1 mRNA expression of osteoblasts in experimental groups were higher than those in control group (P < 0.05). Significant differences of these data were also found among three experimental groups (P < 0.05). Midrange roughness group showed the highest level of gene expression of Cbfα1 mRNA, which was 0.93 ± 0.03. While that in the micro-roughness group (0.50 ± 0.03) came second, and the severe roughness group had the lowest data, which was 0.37 ± 0.07.

CONCLUSIONSResults indicated that rough surface was more suitable for the adherence and propagation of the osteoblasts than smooth one did. Surface with roughness of 1-2 µm may be a better choice for osseointegration between osteoblasts and dental implants than others are.