Effect of Amelotin on Bone Growth in the Murine Calvarial Defect Model.

Amelotin (AMTN) is a protein that is expressed during the maturation of dental enamel and has important role in enamel hydroxyapatite mineralization. However, it is not well understood whether AMTN has a strong mineral-promoting ability in bone. In this study, the effect of AMTN on bone healing was investigated using mice calvarial defect model in vivo, and the expression of bone marker genes and cell proliferation were investigated to clarify the role of AMTN in bone mineralization using mouse osteogenic cells (MC3T3-E1) in vitro. Collagen membranes, with or without recombinant human (rh) AMTN, were applied to calvarial defects created on the parietal bones of C57BL/6N mice. Microcomputed tomography and histological observation revealed that the defect largely filled with mineralized tissue by the rhAMTN-containing membrane in eight weeks. Moreover, CD31 positive cells were observed in the newly formed mineralized tissue and around the rhAMTN-containing membrane. In the presence of rhAMTN, the expression of the Spp1 gene in MC3T3-E1 cells significantly increased within ten days in an osteoinductive medium. Moreover, rhAMTN significantly enhanced MC3T3-E1 cell proliferation. These findings indicate that AMTN positively influences bone repair by promoting hydroxyapatite mineralization.

Application of Glass Fiber and Carbon Fiber-Reinforced Thermoplastics in Face Guards.

Face guards (FGs) are protectors that allow for the rapid and safe return of athletes who are to play after sustaining traumatic facial injuries and orbital fractures. Current FGs require significant thickness to achieve sufficient shock absorption abilities. However, their weight and thickness render the FGs uncomfortable and reduce the field of vision of the athlete, thus hindering their performance. Therefore, thin and lightweight FGs are required. We fabricated FGs using commercial glass fiber-reinforced thermoplastic (GFRTP) and carbon fiber-reinforced thermoplastic (CFRTP) resins to achieve these requirements and investigated their shock absorption abilities through impact testing. The results showed that an FG composed of CFRTP is thinner and lighter than a conventional FG and has sufficient shock absorption ability. The fabrication method of an FG comprising CFRTP is similar to the conventional method. FGs composed of commercial FRTPs exhibit adequate shock absorption abilities and are thinner and lower in weight as compared to conventional FGs.