The effect of surface treatment of titanium with sand-blasting/acid-etching or hydroxyapatite-coating and application of bone morphogenetic protein-2 on attachment, proliferation, and differentiation of stem cells derived from buccal fat pad

This study was performed to evaluate the effect of surface treatment of titanium, including: machined (MA), sand-blasted and acid-etched (SA), and hydroxyapatite-coated (HA) surfaces, and application of bone morphogenetic protein-2 (BMP-2) on attachment, proliferation, and differentiation of stem derived from buccal fat pad. Stem cells were isolated from buccal fat pad. Stem cells were cultured on MA, SA, and HA titanium discs with and without BMP-2. Cellular attachment and alkaline phosphatase (ALP) activity were evaluated at day 3, 7, and 14. Osteocalcin expression was performed using immunofluorescent assay. The cells grown on MA surface demonstrated good attachment with spindle-like morphology, and cells grown on SA and HA surfaces demonstrated more stellate-like morphology. An increase of ALP activity was seen in the rough surface (SA and HA groups) and a statistically significant increase was seen in the HA group (p < 0.05). The addition of BMP-2 made an expression of osteocalcin, and the highest expression of osteocalcin was noted in the HA group. Within the limits of this study, surface modification of titanium surfaces by sand-blasting/acid-etching or hydroxyapatite-coating was not able to allow the stem cells to differentiate into osteoblasts without exogenous soluble factors. The addition of BMP-2 showed osteogenic differentiation of stem cells and HA-coated surfaces demonstrated the highest ALP and osteocalcin expression.