Kimitoshi Yagami

Advanced alveolar bone resorption treated with implants, guided bone regeneration, and synthetic grafting: a case report.

Purpose:To present a vertical ridge augmentation with a composite synthetic bone graft by the mixed bone-filling materials and autogenous bone chips retrieved from the implant osteotomy site for a case for esthetic implant prosthesis on the atrophied alveolar bone. Materials:Nonresorbable and resorbable hydroxyapatite and demineralized freeze-dried bone allograft particles were used at ratio of 1:2:2 (volume ratio). Titanium micromesh was used for alveolar ridge configuration and retention. After 8 months, implant placement and interimplant bone augmentation were performed. Results:15-mm vertical and 10-mm horizontal bone augmentation has been achieved. Marginal bone heights and periimplant mucosa remained stable in cases of loading after >4 years of follow-up. Conclusion:These results suggest that this method has the potential for use in esthetic implant rehabilitation on the highly atrophied alveolar bone.

Nicotine in cigarettes promotes chromogranin A production by human periodontal ligament fibroblasts.

OBJECTIVE The body produces chromogranin A (ChgA) in response to stress as an adaptive reaction. While ChgA is used as an index of autonomic nervous system activity, it is also involved in the immunomodulation system, and an increase in its production in patients with periodontal disease and cigarette smokers has been reported. However, its production in periodontal tissue cells subjected to stress and its immunomodulatory action have not been clarified. To investigate the influence of nicotine on periodontal tissue, we measured ChgA production in nicotine-treated periodontal ligament fibroblasts. DESIGN Using normal human periodontal ligament-derived fibroblasts (HPdLF) as a periodontal tissue model, untreated cells (control) and cells treated with 10 and 100nM nicotine sulfate corresponding to passive and active cigarette smoking, respectively, were cultured for a specific time. The ChgA level in the culture fluid was measured as ChgA production in HPdLF employing ELISA. ChgA gene expression was quantified employing qPCR. In addition, intracellular localisation was confirmed by immunohistochemical staining. RESULTS In the control HPdLF group, a low level of ChgA was produced, and immunohistochemical ChgA-positive reactions were observed in the nucleus and cytoplasm. In the nicotine-treated HPdLF group, the ChgA mRNA expression level, protein production, and immunostaining-positive rate increased, and the levels were higher in the cells treated with 10nM nicotine corresponding to passive smoking than in the cells treated with 100nM nicotine corresponding to active smoking. CONCLUSION Human periodontal ligament-derived fibroblasts (HPdLF) produced ChgA, and nicotine increased ChgA production.

Atelocollagen Enhanced Osteogenesis in a Geometric Structured Beta-TCPScaffold by VEGF Induction

Abstract In order to establish the convertibility of a host for bone augmentation, we herein developed a new honeycombshaped β-tricalcium phosphate (37H) using atelocollagen as a scaffold, which exhibited unique geometric properties for in vitro and in vivo studies. Human mesenchymal stem cells (MSC) were cultured with 37H or atelocollagen-coated honeycomb-shaped β-tricalcium phosphate (Col37H), and their osteoblastic differentiation was then analyzed. Atelocollagen promoted cell adhesion and formation of vessel-like structures in the tunnels of scaffolds of cultured MSC. The mRNA expression levels of type I collagen, osteocalcin, and VEGF were greater in MSC cultured with Col37H than with 37H. Bone generation with Col37H in the rat calvaria was greater than with 37H, and this was attributed to early vessel construction. A large number of blood vessels invaded tunnels from the periosteum and existing bone surface. A strong VEGF signal was detected immediately before the new bone surface in the tunnels of Col37H. These results indicate that the addition of atelocollagen to Col37H has potential in the construction of functional artificial bone.

Honeycomb form β-tricalcium phosphate induces osteogenesis by geometrical property with BMSC

To establish an effective method for bone augmentation, we introduced a new honeycomb-like β-tricalcium phosphate (H-β-TCP) with BMP-2 as a scaffold, whose unique geometrical properties induce osteoblastic differentiation of autologous bone marrow mesenchymal stem cells (BMSCs). A total of six beagle dogs from 6 to 7 years old were used for this study. BMSCs were cultured with autologous serum and BMP-2 on H-β-TCP. Differentiation to osteoblasts was demonstrated in vitro and exo vivo. Scanning electron microscopy revealed formation and calcification of a matrix-like structure within the H-β-TCP tunnels in BMSC culture. Moreover, treatment of BMP-2 promoted osteoblastic differentiation of BMSCs in H-β-TCP in a diffusion chamber. These results indicated that H-β-TCP may be a useful tool for construction of functional artificial bone.