Investigation of Effective Modification Treatments for Titanium Membranes

Titanium membranes are used for guided bone regeneration in implant therapy. However, as a bioinert material, titanium does not have the ability to accelerate bone formation. Various titanium surface treatments to confer bioactivity have been demonstrated; however, there are concerns about the influence of chemical treatments for thin titanium membranes. This study investigated the influence of surface modifications on the structure of titanium membranes. Titanium membranes of 20 μm thickness were treated with acid or alkali solutions, and we evaluated their surface structure, wettability, thickness, and mechanical strength compared to non-treated membranes. Alkali-treated titanium membranes displayed the formation of nanoscale pore structures on their surfaces, enhanced hydrophilicity, and almost same thickness compared with acid-treated membranes. Furthermore, the tensile strength of alkali-treated membranes was comparable to non-treated membranes. These results suggest that alkali treatment is an appropriate surface modification method for titanium membranes

Ameloblastin induces tumor suppressive phenotype and enhances chemosensitivity to doxorubicin via Src-Stat3 inactivation in osteosarcoma

Ameloblastin (AMBN), the most abundant non-amelogenin enamel matrix protein, plays a role in ameloblast differentiation. Previously, we found that AMBN promoted osteogenic differentiation via the interaction between CD63 and integrin β1, leading to the inactivation of Src; however, how AMBN affects the malignant behavior of osteosarcoma is still unclear. Osteosarcoma affects the bone and is associated with poor prognosis because of the high rate of pulmonary metastases and drug resistance. Here we demonstrated that stable overexpression of AMBN induced apoptosis and suppressed colony formation and cell migration via the inactivation of Src-Stat3 pathway in human osteosarcoma cells. Moreover, AMBN induced chemosensitivity to doxorubicin. Thus, AMBN induced a tumor suppressive phenotype and chemosensitivity to doxorubicin via the AMBN-Src-Stat3 axis in osteosarcoma. Indeed, immunohistochemical expression of AMBN was significantly correlated with better outcome of osteosarcoma patients. Our findings suggest that AMBN can be a new prognostic marker and therapeutic target for osteosarcoma combined with conventional doxorubicin treatment

骨新生を目的としたアルカリ処理生体活性チタン薄膜の新規開発に関する研究

広島大学(Hiroshima University)博士(歯学)Doctor of Philosophy in Dental Sciencedoctora

Histological and Bone Morphometric Evaluation of Osseointegration Aspects by Alkali Hydrothermally-Treated Implants

The purpose of this study was to investigate the osseointegration aspects of alkali-treated implants by histological and bone morphometric evaluations. Titanium implants (control) and alkali hydrothermally-treated titanium implants were used. Samples were evaluated by surface structure observation and wettability tests. Both implants were placed into the femurs of five rabbits, and osseointegration was assessed by measurement of removal torque (RT), bone–implant contact ratio (BIC), and bone tissue area ratio (BTA). Measurements were performed at the whole portion around the implant, the cortical bone portion, and the bone marrow portion. The surface structure of alkali-group showed nanoscale pores and super hydrophilicity. RT, BIC, and BTA values of alkali-group were significantly higher than those of control-group at the whole portion. In the cortical bone portion, the BIC value was higher in the alkali-group than in the control-group, and BTA showed no significant difference between groups. In the bone marrow portion, even though no significant difference between control and alkali groups, the latter had higher ratio of BIC than the former. These results indicate that alkali treated implants enhance bone integration in areas where the implant is in contact with bone, and may promote osteoinduction in the non-bone marrow portion

Investigation of Effective Modification Treatments for Titanium Membranes

Titanium membranes are used for guided bone regeneration in implant therapy. However, as a bioinert material, titanium does not have the ability to accelerate bone formation. Various titanium surface treatments to confer bioactivity have been demonstrated; however, there are concerns about the influence of chemical treatments for thin titanium membranes. This study investigated the influence of surface modifications on the structure of titanium membranes. Titanium membranes of 20 μm thickness were treated with acid or alkali solutions, and we evaluated their surface structure, wettability, thickness, and mechanical strength compared to non-treated membranes. Alkali-treated titanium membranes displayed the formation of nanoscale pore structures on their surfaces, enhanced hydrophilicity, and almost same thickness compared with acid-treated membranes. Furthermore, the tensile strength of alkali-treated membranes was comparable to non-treated membranes. These results suggest that alkali treatment is an appropriate surface modification method for titanium membranes