Effect of Titanium Surface Textures on Growth/proliferation of Rat Pre-osteoblasts

Considerable interest has been generated recently, concerning the effect of surface roughness on osteoblast attachment and proliferation. Objectives: This study characterized attachment and proliferation of rat pre-osteoblast cells on disks of material having differing surface textures. Methods: Commercially-pure titanium discs (1mm x 15.5mm) were prepared with three different surface textures: smooth(ST); grit-blasted(GBT); and grit-blasted followed by acid-etching(AET). In addition, disks of polymethylmethacrylate (PMMA) with both smooth(SP) and grit-blasted(GBP) textures were tested. Empty tissue culture-treated polystyrene wells(PS) were used as internal controls. Disks were ultrasonically cleaned prior to testing. To obtain pre-osteoblasts, calvarae from day 19 fetal Sprague Dawley rats were pooled and treated with collagenase to liberate the cells. Cells were allowed to recover for three days prior to plating. Material discs were placed in 24-well culture plates, and each well received 1.0 mL of cell suspension (10,000 cells). Quantification of cell viability within the test wells was measured at predetermined times of 4, 24, 48, 96, 120, 216, and 288 hours by observing the reduction of 10% Alamar Blue nuclear dye using a fluorescent colorimeter. Significance was determined using Students t-test with a=0.05 Results: GBP showed initial superiority to SP at the 4 hour time, but this difference was gone by 24 hours. These two materials were equivalent throughout the remainder of the times. ST had higher cell numbers than GBT and AET at 4, 24, and 120 hours. Cell counts for ST stayed significantly higher than AET through the 216 hr time. At the final time, however, the GBT had higher cell counts than either ST or AET. Conclusions: Surface texture plays an important role in cell anchorage and proliferation on titanium surfaces. Smooth titanium surfaces may provide superior initial pre-osteoblast attachment, but this effect is transitory and during growth and proliferation, a rougher surface is optimal.