Biological Effects of Double-Layered Hydroxyapatite and Zirconium Oxide Depositions on Titanium Surfaces

Min-Kyung Ji,1,&ast; Yaerim Chun,2,&ast; Geonwoo Jeong,3 Hyun-Seung Kim,4 Won-Jae Kim,5 Je-Hwang Ryu,6 Hoonsung Cho,3 Hyun-Pil Lim1,2 1Dental 4D Research Center, Chonnam National University, Gwangju, Republic of Korea; 2Department of Prosthodontics, School of Dentistry, Chonnam National University, Gwangju, Republic of Korea; 3Department of Materials Science and Engineering, Chonnam National University, Gwangju, Republic of Korea; 4KJ Meditech Co., Ltd, Gwangju, Republic of Korea; 5Department of Oral Physiology, School of Dentistry, Stem Cell Secretome Research Center, Chonnam National University, Gwangju, Republic of Korea; 6Department of Pharmacology and Dental Therapeutics, School of Dentistry, Chonnam National University, Gwangju, Republic of Korea&ast;These authors contributed equally to this workCorrespondence: Hyun-Pil Lim, Department of Prosthodontics, School of Dentistry, Chonnam National University, Gwangju, 61186, Republic of Korea, Tel +82-10-2645-7528, Fax +82-62-530-5577, Email mcnihil@jnu.ac.kr Hoonsung Cho, Department of Materials Science and Engineering, Chonnam National University, Gwangju, 61186, Republic of Korea, Tel/Fax +82-62-530-1717, Email cho.hoonsung@jnu.ac.krPurpose: This study aimed to confirm the synergy effect of these two materials by evaluating osteoblast and antibacterial activity by applying a double-layered hydroxyapatite(HA) zirconium oxide(ZrO2) coating to titanium.Methods: The specimens used in this study were divided into four groups: a control group (polished titanium; group T) and three experimental groups: Group TH (RF magnetron sputtered HA deposited titanium), Group Z (ZrO2 ALD deposited titanium), and Group ZH (RF magnetron sputtered HA and ZrO2 ALD deposited titanium). The adhesion of Streptococcus mutans (S.mutans) to the surface was assessed using a crystal violet assay. The adhesion, proliferation, and differentiation of MC3T3-E1 cells, a mouse osteoblastic cell line, were assessed through a WST-8 assay and ALP assay.Results: Group Z showed a decrease in the adhesion of S. mutans (p < 0.05) and an improvement in osteoblastic viability (p < 0.0083). Group TH and ZH showed a decrease in adhesion of S. mutans (p < 0.05) and an increase in osteoblastic cell proliferation and cell differentiation (p < 0.0083). Group ZH exhibited the highest antibacterial and osteoblastic differentiation.Conclusion: In conclusion double-layered HA and ZrO2 deposited on titanium were shown to be more effective in inhibiting the adhesion of S. mutans, which induced biofilm formation, and increasing osteoblastic differentiation involved in osseointegration by the synergistic effect of the two materials.Keywords: zirconium oxide, hydroxyapatite, atomic layer deposition, radio frequency magnetron sputter, osteoblast activity, antibacterial effect