Analysis of the Attachment and Differentiation of Three-Dimensional Rotary Wall Vessel Cultured Human Preosteoblasts on Dental Implant Surfaces

Purpose: The purpose of this study was to determine whether osseous tissues engineered in three-dimensional (3D) environments preserved their mineralizing capacity and retained biologic characteristics when cultured on dental implant surfaces. Materials and Methods: Human preosteoblast cells were cultured in both 3D rotary wall vessels and on 2D tissue culture plastic plates for 3 days. Aggregates from the 3D chambers and cells from the 2D plates were collected and transferred to commercially pure titanium disks with either 600-grit polished or sandblasted surfaces. These were cultured for an additional 7 days. The aggregates and cells from the disks were collected and prepared for scanning electron microscopy for microscopic evaluation and atomic adsorption assays for mineral content analysis. Additionally, staining with Alizarin red S was performed to compare the mineralization amount and pattern in each group. Polymerase chain reaction analysis was performed to evaluate expression of osteogenic genes, including Runx2, FAK, bone morphogenetic protein 2, and osteocalcin. Results: Cells from 3D rotary wall vessel cultures attached to implant surfaces and presented cell attachment and growth patterns similar to those of standard 2D cultured cells, showing evidence of radial and random growth, yet they formed multiple focal niches on implant surfaces out of which cells proliferated. The 3D cultured cells and osseous tissues retained higher amounts of mineral formed during the initial culture and showed a higher tendency toward mineralization on implant surfaces compared to standard cultured cells. The 3D cultured cells and osseous tissues on implant surfaces at 1 week showed higher key gene protein expression. RNA expression at 1 week was equivalent to that of standard cultured cells. Conclusion: Culture of human osteogenic cells and tissues in 3D rotary wall vessels may expedite the osseointegration process on dental implant surfaces, thus reducing the overall treatment time. Keywords: dental implant, osseointegration, osteoblast, tissue engineering