Effects Of TPS And TiO₂ Blasted Titanium Surfaces On Osteoblast Responses

[Objective] To evaluate the effects of TPS and TiO₂ blasted surfaces of titanium substrates on morphology, attachment, proliferation and differentiation of osteoblasts in vitro.[Materials and Methods] Osteoblasts derived from fetal rat calvarial were cultured on 5 different commercially pure titanium (cpTi) substrates—smooth(So), sandblasted (S₁, S₂, S₃) and titanium plasma sprayed (TPS) surfaces, S₀ surfaces as control. S₀ surfaces were prepared by hand grinding with SiC paper to 600 grits. S₁, S₂ and S₃ surfaces were sandblasted by TiO₂ particles, sized 108-130μm, 216-301μm and 356-411μm respectively. For morphology and attachment measurement, osteoblasts were cultured for 1,4, 12 and 24 hours , evaluated by SEM observation and MTT Assay. MTT Assay, ALP activity and Osteocalcin(OC) content were evaluated after 1, 3, 5 and 7 days for osteoblast proliferation and differentiation evaluation. Data were analyzed by one-way ANOVA (a = 0.05).[Results] SEM for analysis of cell morphology Osteoblasts attached to the different types of surfaces after 1 hour culture were round and similar. As time going on, on all experimental surfaces the cells were flat, well spread except that osteoblasts were spindle-shaped on S₀ surfaces. Osteoblast Attachment After 1 hour culture, the number of cells on S3 surfaces was the highest(P<0.05) while it was similar on So, S₁, S₂ and TPS surfaces (P>0.05) .After 4 hours, S₃ surfaces was the highest (P<0.05) . S₁ or S₂ surfaces was similar to TPS surfaces. The number of cells on S₃ surfaces was the same (P>0.05) as TPS surfaces and higher than other groups (P<0.05) after 12 hours. There was no difference between S₁ and S₂ surfaces (P>0.05) . After 24 hours, there was no difference between S₃ and TPS surfaces (P>0.05) and both were higher than other groups (P<0.05) . S₂ surfaces was higher than S₁ surfaces (P<0.05) .All experimental groups were higher than S₀ surfaces after 4, 12, 24 hours (P<0.05) .Osteoblast Proliferation The number of cells was the highest on S3 and TPS surfaces after 1 day culture. The same results were observed after 5 days. On day 3 and 7, S3 surfaces was the highest (PO.05) . The number of cells on all experimental groups was higher than So surfaces at each time point (PO.05) . ALP Measurement An increase in ALP activity was detected on So, Si, S2 and S3 surfaces after 1, 3, 5 days. However, there was no difference between S3 and TPS surfaces (P>0.05) . After 7 days, ALP activity increased significantly on TPS surface than on Si or S2 surfaces. And S3 surfaces was the highest (PO.05). OC content An increase in OC production was detected on So, Si, S2 and S3 surfaces after 1,3, 5days. And S3 surfaces was the highest on day 7 (P<0.05 ) . The ALP activity on all experimental groups were higher than So surfaces at each time point (PO.05) .[Conclusions]It was concluded that osteoblast attachment, growth, proliferation and differentiation were better on S3 surfaces than on Si and S2 surfaces. Osteoblasts spread well on So, Si, S3 and TPS surfaces. For TiO2 sandblasted surfaces, Ra ranging from 1.260nm to 3.530um would optimize both initial osteoblast response such as attachment, spread and subsequent response such as proliferation and differentiation. But TPS surfaces didn't exhibit any virtue than surfaces sandblasted with large T1O2 particles. An optimal surface roughness or treatment method for osteointegration may be existed.