Journal of Hard Tissue Biology
Online ISSN : 1880-828X
Print ISSN : 1341-7649
ISSN-L : 1341-7649
Volume 15, Issue 2
Displaying 1-6 of 6 articles from this issue
Review
  • Michel Goldberg, Sally Lacerda-Pinheiro, Nadege Jegat, Ngampis Six, Do ...
    2006 Volume 15 Issue 2 Pages 36-45
    Published: 2006
    Released on J-STAGE: November 22, 2006
    JOURNAL FREE ACCESS
    Dentin extracellular matrix proteins display multifunctional properties. Firstly, they participate to the mineralization processes either as promotors or as inhibitors of crystal nucleation or crystal growth. Secondly, they act as signaling molecules implicated in the differentiation of odontoblast progenitors. These molecules may be used to promote the recruitment of odontoblast progenitors, the proliferation and the final differentiation into functional odontoblast-like or osteoblast-like cells implicated in pulp repair. This has been evaluated through a series of experiments carried out in vivo on the rat first maxillary molar and in vitro on odonto/osteo progenitors. Along this line, BMP7 (OP1) induced in the crown a fibrous osteodentin-like structure where unmineralized pulp remnants were seen. In addition, the mesial root canal was totally filled with a homogeneous dentin-like structure. The bone sialoprotein (BSP) stimulated within one month the formation of a reparative dentinal bridge and the complete closure of the coronal pulp with an atubular homogeneous reparative dentin. Dentonin, a peptide from MEPE, implantated into the exposed pulp produced more rapidly than the two previous molecules reparative mineralization in the coronal pulp and also occlusion of the lumen of the root canal. Implanted in the exposed pulp, A+4 and A-4, two spliced amelogenin gene products, induce either the formation of a reparative dentinal bridge (A+4) or a more diffuse mineralization (A-4). The mechanisms of proliferation and differentiation were studied in parallel in an in vivo situation after implantation in the first maxillary molar of the rat, and in vitro on odontoblast progenitor cell lines. These molecules may contribute to pulp repair and promote new strategies in dental therapies.
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Original
  • Phuu Pwint Han, Ryo Tamamura, Naoki Katase, Eiki Fujii, Mika Okauchi, ...
    2006 Volume 15 Issue 2 Pages 46-53
    Published: 2006
    Released on J-STAGE: November 22, 2006
    JOURNAL FREE ACCESS
    Type IV collagen is the principal constituent component of the basement membrane(BM). It have been reported that the alpha chains of type IV collagen [α(IV)] showed temporal and spatial localization pattern in different stages of the developing tooth germ except α3(IV) chain. In this study, we investigated the localization of α(IV) chains in benign odontogenic tumor in comparison with their localization in the cap stage human tooth germ by immunohistochemistry. All the tumor samples studied as well as the tooth germ were negative to α3(IV). In ameloblastoma that resembles the enamel organ of the tooth germ, all types of tumor (follicular, plexiform and desmoplastic) were not reactive to α4(IV) chains similar to the α(IV) chains composition in the BM of outer enamel epithelium and dental lamina. All α(IV) chains except α3(IV) were localized in the tumors in which the odontogenic epithelium is accompanied by odontogenic ectomesenchyme like adenomatoid odontogenic tumor (pseudoglandular spaces), odontoma and ameloblastic fibroma and this is similar to the α(IV) chains composition in the BM of inner enamel epithelium of the tooth germ. From the results, the presence of α4(IV) chains is thought to be important for the differentiation and induction of the dental papilla like tissue formation in odontogenic tumors.
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  • Qu Hong, Tan Jun, Jin Lei, Jing Xiling, Ryo Tamamura
    2006 Volume 15 Issue 2 Pages 54-60
    Published: 2006
    Released on J-STAGE: November 22, 2006
    JOURNAL FREE ACCESS
    Oral squamous cell carcinoma is the most common malignant tumour in the head and neck area, and is considered as the top oral carcinoma. A large number of studies have determined that many matrix matalloprpteinases (MMPS), especially MMP-2 and MMP-9 are eminent, correlative with Oral squamous cell carcinoma (OSCC)'s invasion and metastasis. However, the research on the expression of MMP-2 and its inhibitor (TIMP-2) in oral squamous cell carcinoma is very rare. Here we examine the expression pattern of MMP-2 and TIMP-2 in 10 normal oral mucosa, 10 dysplastic oral mucosa and 30 oral squamous cell cancer tissues, using immunohistochemical method in order to investigate the correlativity and the effect to the biological behaviour of Oral Squamous Cell Cancer. We found that the difference of MMP-2 expression in oral squamous cell cancer tissues, and dysplastic oral tissues versus normal oral tissues was statistically significant. There is a close correlation between the MMP-2 expression level and the carcinoma differentiation, depth of invasion, lymph node metastasis, and distant metastasis. The expression of TIMP-2 in oral squamous cancer was higher than in normal oral mucosa but lower than in dysplastic mucosa. The difference of the expression of TIMP-2 in positive and negative lymphnode metastasis was significant. There is an inverse correlation between the MMP-2 expression and the TIMP-2 expression in oral squamous cell carcinoma tissues (r=3.89 p<0.01). In the process of invasion and metastasis of OSCC, imbalance between MMP-2 and TIMP-2 expression plays an important role. Detecting MMP-2 and TIMP-2 protein expression may be considered as markers for estimating the biological behavior of carcinoma and evaluating the prognosis of patients.
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  • Masahisa Inoue, Racquel Z. LeGeros, Miho Inoue, Rsario Santos Rivera, ...
    2006 Volume 15 Issue 2 Pages 61-64
    Published: 2006
    Released on J-STAGE: November 22, 2006
    JOURNAL FREE ACCESS
    Fluoride as a supplement can affect the structural integrity of bone. Fluoride that is incorporated in the mineral, substitutes for the hydroxyl group producing hydroxyfluorapatite crystals and presumed to increase bone strength by preventing resorption. Because of this, fluoride therapy has been carried out in clinical trials for the treatment of osteoporosis. Although fluoride renders the mineralized tissues resistant to resorption, the effects of fluoride on bone strength and cortical bone mass specially that of the developing bone has not yet been characterized. The purpose of the study was to analyze the effect of fluoride on developing teeth and bone in young rats through histomorphometry. Sixteen wistar rats were used and divided into two groups; non-fluoride supplemented (control) and fluoride-supplemented groups. Four weeks after, the rats were sacrificed and the mandible and femur were subjected to histological and histomorphometric analyses. No clinical difference was observed between the two groups. The amount of mineralized cartilage was higher in fluoride-supplemented group compared to the control group. However, the amount of new bone was lesser in fluoride-supplemented group compared to the control group. This histomorphometric analysis showed that during endochondral ossification, 10 ppm fluoride administration caused some changes in calcified cartilage and bone mineralization in young rats.
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  • Baohong Zhao, Zhe Yi, Zhenfu Lu, Weiming Tian, Fuzhai Cui, Hailan Feng ...
    2006 Volume 15 Issue 2 Pages 65-68
    Published: 2006
    Released on J-STAGE: November 22, 2006
    JOURNAL FREE ACCESS
    Objective: Arg-Gly-Asp(RGD)-containing peptide was coupled on titanium surface of dental implants. It is confirmed that this peptide promotes human gingival fibroblasts (HGFs) adhesion during the early stage after implantation was tested. Methods: RGD peptides were attached covalently to the titanium surface by 1,1'-carbonyldiimidazole (CDI). Primary HGFs were inoculated on commercially pure titanium and RGD-grafted titanium respectively. Cell attachment and proliferation was assessed by acridine orange staining technology. Cell spreading were checked by immunofluorescence staining and confocal laser scanning microscope. Results: The number of attached and proliferated HGFs and their average spreading area were higher on RGD modified titanium than on unmodified titanium. The actin cytoskeleton reorganization existed earlier on RGD coated samples than on uncoated ones. Conclusions: This research may develop a new potential method to enhance the integration between human gingival soft tissue and titanium implant surfaces.
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  • Yang Zhang, Dan Zhang, Cuijuan Feng, Peng Peng, Hailong Hu, Toshiyuki ...
    2006 Volume 15 Issue 2 Pages 69-72
    Published: 2006
    Released on J-STAGE: November 22, 2006
    JOURNAL FREE ACCESS
    Objective: To establish a three-dimension finite element model for orthodontic anchorage micro-implant and analyze the influence of different titled angle on the biomechanical characteristics of orthodontic anchorage implant-bone interface. Methods: Use ANSYS (Analysis System) finite element analysis software to perform the finite element modeling of the micro-implant with 7 different tilted angle, including 30°, 40°, 50°, 60°, 70°, 80° and 90°. A simulated orthodontic force, which was 200 grams, was loaded mesiodistally to the mathematical models, the stress and displacement distribution on the implant-bone interface was analyzed. Results: As the titled angle increased , the Von-Mises stress at the cervix of the implants were 1.0792Mpa, 1.0104Mpa, 0.8848Mpa, 0.8181Mpa, 0.7583Mpa, 0.6339Mpa and 0.5608Mpa while the displacement were 5.5513μm, 4.9900μm, 3.7419μm, 3.1264μm, 2.5874μm, 1.3624μm and 0.8027μm. Conclusion: The micro-implant can be safely loaded with 200 grams mesiodistal orthodontic force. The increase of the titled angle can efficaciously enhance the implant's ability of bearing mesiodistal orthodontic force. Thus we should choose the vertical angle when the micro-implant is embedded.
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