Fig. 1.

Effects of heat and RFGD pretreatments of Ti6Al4V disks on total soluble calcium levels in MC3T3 osteoprogenitor cell cultures. Both untreated and pretreated disks were either uncoated (No FN) or precoated (FN) with 1 nM fibronectin overnight and plated with MC3T3 cells. Cultures were incubated for 1–4 weeks in cell culture media containing 50 μg/ml ascorbic acid and 3mM β glycerophosphate. Total soluble calcium was extracted from the surface of disks at the indicated incubation time points and measured by flame atomic absorption spectrophotometry. Total soluble calcium levels are presented as umoles/disk. Data represent means ±SE for a minimum of four independent cultures at each time point. *,**Significantly greater (P <0.05) than untreated No FN disks or untreated FN disks, respectively, measured at the same time point based on analysis of variance. ^a–c Significantly greater compared to the same experimental condition measured at 1 week (P <0.05 or less); 1 and 2 weeks (P <0.05 or less); or 1, 2, and 3 weeks (P <0.01 or less), respectively, based on analysis of variance. FN, fibronectin; HEAT, heat pretreatment; RFGD, radiofrequency plasma glow discharge pretreatment.