**Coating of a Sand-Blasted and Acid-Etched Implant Surface with a pH-Bu**ff**ering Agent after Vacuum-UV Photofunctionalization**

**Chang-Joo Park 1,**†**, Jae Hyung Lim 2,**†**, Marco Tallarico 3, Kyung-Gyun Hwang 1, Hyook Choi 1, Gyu-Jang Cho 1, Chang Kim 1, Il-Seok Jang 4, Ju-Dong Song 4, Amy M. Kwon 5, Sang Ho Jeon <sup>6</sup> and Hyun-Kyung Park 7,\***


Received: 24 September 2020; Accepted: 28 October 2020; Published: 28 October 2020

**Abstract:** Ultraviolet (UV) photofunctionalization can reset the biological aging of titanium after the preparation and storage of dental implants by transforming hydrophobic titanium surfaces into superhydrophilic surfaces. Blood clot formation around the implant can initialize and promote the healing process at the bone–implant interface. The aim of this study is to evaluate and compare the capabilities of surface wettability and blood clotting of implants with a conventional sand-blasted and acid-etched surface (SA), a sand-blasted and acid-etched surface with vacuum-UV treatment (SA + VUV), and a sand-blasted and acid-etched surface coated with a pH-buffering agent after vacuum-UV treatment (SA + VUV + BS). Static and dynamic tests for surface wettability and blood clotting were performed in vitro for SA + VUV and SA + VUV + BS (*n* = 5), while hemostasis resulting from blood clotting was evaluated in vivo for SA, SA +VUV, and SA + VUV + BS (*n* = 4). A Kruskal–Wallis test showed statistically significant differences (*p* < 0.05) in all tests, with the exception of in vitro test of static blood clotting. VUV treatment is therefore effective at making an SA surface superhydrophilic as an alternative to routine UV-C radiation. The addition of a pH-buffering agent to SA + VUV also improved surface wettability and blood clotting, which are crucial for successful osseointegration.

**Keywords:** blood clotting; dental implants; hydrophilicity; titanium; ultraviolet rays
