Influence of Rat Dental Pulp-derived Cells on Bone-titanium Implant Integration

Objectives: In implant therapy it is necessary to acquire good osseointegration earlier and a number of various approaches using titanium and cells have been attempted. Mesenchymal cells exist in dental pulp and dental pulp-derived cells have been confirmed to form osseous hard tissues in vitro. However, to date there have been few studies of the application of dental pulp-derived stem cells to implant therapy. In this study, we incubated osteoblast-like cells that were derived from rat incisor pulp on titanium discs and evaluated their proliferation and differentiation potential. We further examined the possibility of the application of dental pulp-derived cultured cells when implanting a titanium implant.
Methods: In this study, dental pulp cells were collected from the incisors of 8-week old, male SD rats and then incubated on titanium discs. Two different kinds of titanium discs were prepared. Titanium discs treated with sulfuric acid, as the control group, and those treated with sulfuric acid after sandblasting with alumina, as the experimental group. Cell proliferation and differentiation potential were assessed by WST-1, alkaline phosphatase (ALP) activity, alkaline phosphatase (ALP) staining and alizarin red staining. Furthermore, dental pulp-derived cultured cells were used in the implant test to measure the mechanical strength of the bone-titanium integration.
Results: ALP activity and the area of ALP- positive staining increased significantly in cultured cells after 10 days compared with 5 days. The area of alizarin red-positive staining increased significantly in a time-dependent manner after incubation for 10, 20 and 30 days. The mechanical strength achieved 2 weeks after implanting in the experimental group was significantly greater than that in the control group.
Conclusions: The results of this study showed that osteoblast-like cells derived from rat dental pulp incubated on surface-treated titanium discs maintained cell differentiation potential. The results of the implant test indicated the potential application of dental pulp-derived cells to achieve good osseointegration of titanium implants earlier.