[Fundamental study on hybrid-type dental implant--effects of glass-ceramics on growth and differentiation of human periodontal ligament-derived cells].

The hybrid-type dental implants which are composed of substrates and periodontal ligament-derived cells are expected to form the periodontal ligament-like tissue around the dental implant. The purpose of this study was to investigate the possibility of the application of glass-ceramics (GC) as the substrate using the human periodontal ligament-derived cells (PL cells). The growth and differentiation of the PL cells on the GC were investigated, as compared to the hydroxyapatite plates and the conventional plastic dishes. The Ca concentration of the media was also measured. The results were as follows: 1) The PL cells were fibroblastic of spindle shape. The population doubling time was approximately 26 hours. 2) The PL cells exhibited an alkaline phosphatase (ALPase) activity, collagen productivity and responsiveness to 1 alpha,25-dihydroxyvitamin D3. 3) The PL cells proliferated favorably both on the mirror-polished and #2000-polished GC plates as well as on the hydroxyapatite plates. 4) The ALPase activity of the PL cells on the GC increased in a time-dependent manner. 5) The GC released Ca into the media. The PL cells possessed some characteristics of periodontal ligaments, and the growth and differentiation of the PL cells were not impaired significantly on the GC. The GC also provided the dental implant with enough biocompatibility and strength. These results promised the usefulness of the GC as the possible substrate for the hybrid-type dental implants.