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OBJECTIVE: Periodontal ligament has been reported to have adult stem cells (PDLSCs) which are responsible to regenerate the alveolar bone tissue after tooth is removed from its socket. Also PDLSCs may be the stem cells responsible for the osseointegration of titanium implants after installing the implant immediately in the fresh extracted socket. Here we tested cellular responses of PDLSCs on the various titanium surfaces to verify this notion. MATERIALS AND METHODS: Titanium disc were prepared for the different surface textures; smooth machined, blasted with 75 and 125 μm Al2 O3 particles, and anodized. PDLSCs were cultured on these titanium discs and tested their proliferation and gene expressions of osteocalcin, osteopontin, type I collagen, and GAPDH. RESULTS: Proliferation of PDLSCs was higher on the rough surface blasted with 75 μm Al2 O3 particles. Osteocalcin expression was increased on the Al2O3 particle treated-surface regardless of its particle size. Type I collagen expression was generally decreased with time in 6 days culture. CONCLUSIONS: In this experiment, it was shown that cultured PDLSCs proliferate in higher rate on the rough surface especially at the 75 μm Al2O3 particle treated surface than other surfaces. Also, osteocalcin was highly expressed on the rough surfaces treated with 75 μm and 125 μm Al2O3 particles. ; This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (No. M10646010003-06N4601-00310). ; 2

Liquid metal dealloying (LMD) has recently attracted significant attention. Because the LMD process enables the production of three-dimensional (3D) interconnected non-noble metallic materials. In addition, the metallic melt medium is useful for the development of heterostructure (HS) metal–metal composites. However, the solidified liquid metal phase (low melting point metals such as Mg, Bi, Sn, or Cu) has a much lower strength than the developed ligament phase (e.g., Fe, FeCr, Ti, etc.). In this study, the soft Mg phase was strengthened by adding alloying element of Ni. A eutectic composition of Mg–10 at.% Ni melt leads to the formation of fine eutectic structure of (Mg–Mg2Ni) within 3D interconnected morphology. This hierarchical heterostructured composite consisted of FeCr ligament and Mg–Mg2Ni lamellar, and a high yield strength of 280 MPa and a noticeable elongation (1.5%) were achieved. The complex 3D morphology of ligament and lamellar geometrically constraint each other, and it prevents the early fracture of brittle Mg–Mg2Ni lamellar phase. The alloy design for the LMD melt gives insights for hierarchical HS materials with outstanding mechanical properties for structural applications. © 2021 The Authors. ; This work was supported by JSPS KAKENHI (Grant Number JP20J14001 ). Yeonbeom Jeong acknowledges the support from the GP-MS at Tohoku University . This work has supported by the National Research Foundation of Korea grant funded by the Korea government(MSIT) (No. NRF-2021R1C1C1007645 ). This work was primarily supported by a Grant-in-Aid for Scientific Research on Innovative Areas "Science of New-Class of Materials Based on Elemental Multiplicity and Heterogeneity (Grant No. 18H05452)" from the Ministry of Education, Culture, Sports, Science, and Technology (MEXT, Japan) (H.K and T.W). This work was performed under the ICC-IMR Program of the Institute for Materials Research, Tohoku University.