Effect of Macroscopic Grooves on Bone Formation and Osteoblastic Differentiation.

OBJECTIVES The aim of this study is to investigate the effect of macroscopic grooves on bone formation in vivo and differentiation of human mesenchymal stem cells (hMSCs) in vitro. MATERIALS AND METHODS The effects of macroscopic grooves on titanium alloy implants and disks were tested in rabbit tibiae and cultured hMSCs. The bone-to-implant contact (BIC) and bone area were evaluated in rabbit tibiae at 6 and 24 weeks after implant insertion. Osteoblastic differentiation was assessed by alkaline phosphatase (ALP) activity and real-time reverse-transcription polymerase chain reaction (RT-PCR) on days 7, 14, and 21. All values were statically analyzed. RESULTS BIC and bone area inside the grooves were significantly higher than those of control implants (P < 0.05). ALP activity was significantly higher for titanium disks with macroscopic grooves than without grooves on day 14 (P < 0.05). Real-time RT-PCR showed that the expression of osteogenic genes was significantly higher for disks with grooves on day 7 (P < 0.01). CONCLUSIONS Macroscopic grooves accelerate osteoblastic differentiation in vitro and stimulate direct bone growth and deposition within the grooves in vivo.