It is necessary to acquire osseointegration at an early stage in implant therapy, and a number of various approaches using titanium and cells have been evaluated. Mesenchymal cells exist in dental pulp and have been confirmed to form osseous hard tissues in vitro. However, there have been few studies on the application of dental pulp-derived stem cells in implant therapy. In this study, we cultured osteoblast-like cells derived from rat incisor pulp on titanium discs and evaluated their proliferation and differentiation potential. We further examined the possibility of applying dental pulp-derived cultured cells during titanium implant placement. Dental pulp cells were collected from the incisors of SD rats and then cultured on titanium discs. The titanium discs were treated with sulfuric acid after sandblasting with alumina. Cell proliferation and differentiation potential was evaluated by WST-1 assay, alkaline phosphatase (ALP) activity, and Alizarin red staining. Finally, the dental pulp-derived cultured cells were used in an implant test to measure the mechanical strength of the bone-titanium integration. ALP activity was significantly increased in cultured cells after 10 days compared with that after 5 days. The area of Alizarin red-positive staining increased significantly in a time-dependent manner upon incubation for 10, 20, and 30 days. The mechanical strength achieved at 2 weeks after implantation in the experimental group was significantly greater than that in the control group. These results demonstrate that osteoblast-like cells derived from rat dental pulp and cultured on surface-treated titanium discs maintained their cell differentiation potential. The results of the implant test cultured the potential application of dental pulp-derived cells to rapidly achieve osseointegration of titanium implants.

The purpose of this study was to investigate the relationship between the bone mineral density and the contents of osteocalcin calcium and phosphorus in serum with temporomandibular joint osteoarthrosis (TMJOA). The mineral densities of lumbar and neck of femur research groups, including the case group and the control group, were compared. The contents of osteocalcin calcium and phosphorus in serum were also measured and evaluated. The results showed that the mean bone mineral density of the case group (TMJOA group) was lower than that of the control group (healthy control). However, a statistical difference was not reflected. The mineral density of the neck of femur of the case group is lower than that of the controlled group obviously, suggesting that mineral density of the femur was related with TMJOA. It was presumed that the bone mineral density of the femur neck might have relationship with TMJOA. The level of osteocalcin in serum of the case group was significantly lower than that of the control group. Thus it is presumed that osteocalcin had a relationship with TMJOA. The results showed that the capability of bone transformation and formation in TMJOA were all decreased. No relationship was found between calcium phosphorus in serum and TMJOA.