Osteoblastic Differentiation Potency of C2C12 Cells Cultured on Zirconia Disc

Zirconia is a ceramic which has a superior biocompatibility and high mechanical strength, and is used as the abutment of dental implants. Objective: To examine the adaptability of zirconia as a fixture by comparing the proliferation and osteoblastic differentiation potency of mouse C2C12 myoblast (C2C12) cells on zirconia discs with those on titanium discs or slide glass. Methods: The C2C12 cells were seeded on the cerium-stabilized tetragonal zirconia polycrystals/aluminum oxide nanocomposite (NANOZR) discs (10 mm in diameter, 0.5 mm in thickness) made of 10 mol CeO₂-ZrO₂/30% vol of AlO_3, titanium disc (10 mm in diameter, 0.7 mm in thickness) and poly-L-lysine coated slide glass (10 mm in diameter, 0.12-0.17 mm in thickness). The cells were maintained in αMEM containing 10% FBS and 1% antibiotics at 37°C in a humidified 5% CO₂ atmosphere and the proliferation potency of cells were determined by counting cells. In the study of mineral induction, the C2C12 cells on each disc were incubated for 5 days in growth medium containing L-ascorbic acid, β-glycerophosphate, all-trans retinoic acid and recombinant bone morphogenetic protein 2. The osteoblastic differentiation potency was determined by both alkaline phosphatase (ALP) and alizarin red (ARS) staining. Furthermore, the ALP activity and quantitative analysis of calcium were assayed and determined in C2C12 cells on each disc. Results: The number of cells on each of three discs was almost equal, which suggested no significant differences among three discs as for cell proliferation. Both ALP and ARS staining for C2C12 cells after the mineral induction showed densely-stained images, which induced C2C12 cells to express the phenotype of osteoblasts. With regard to ALP activity and calcium concentration of C2C12 cells, no significant difference was observed between Zirconia and titanium discs. Conclusions: These results suggest that the zirconia has a great potential as the fixture of dental implants.