*2.3. In Vivo Test*

A beagle dog mandible model was used. All procedures were conducted with the approval of the Ethics Committee of Animal Experimentation of the Institutional Animal Care and Use Committee (CRONEX-IACUC 20191002; Cronex, Hwasung, Korea) according to the guidelines of Animal Research: Reporting in Vivo Experiments (ARRIVE).

Four female beagles 18 months of age were subjected to bilateral extraction of their mandibular premolars and the first molar under general anesthesia. The anesthetic protocol for all surgical procedures included a 1 mL intramuscular injection with a 15 mg/kg dose of tiletamine/zolazepam (Zoletil 50, Virbac, Seoul, Korea) and 5 mg/kg xylazine (Rompun, Bayer Korea, Seoul, Korea). After local anesthesia, a full-thickness mucoperiosteal flap was raised adjacent to the mandibular premolars and molars (Figure 3). Teeth were hemisected under copious irrigation with a small fissure bur. Extractions were performed with elevators and forceps. Flaps were closed with single interrupted sutures. Postoperative care protocol included antibiotics and pain control. During this interval, all dogs were maintained on a soft diet and water ad libitum.

**Figure 3.** In vivo test of blood clotting: (**a**) incision and flap reflection; (**b**) alveolar ridge flattening; (**c**) preparation of implant holes; (**d**) implant fixture placement; (**e**) cotton pellet application for bleeding absorption; (**f**) pattern of cotton pellets according to time. SA, a conventional SA surface; SA + VUV, an SA surface with vacuum-UV treatment; SA + VUV + BS, an SA surface coated with a pH-buffering agent after vacuum-UV treatment.

Three months after the extractions, surgical placement of dental implants was performed in the healed extraction sites under sterile conditions. After local anesthesia, a full-thickness flap was elevated to expose the alveolar ridge, and the irregular alveolar crestal was flattened. Sequential drillings were performed for consecutive implant sites, which were larger than the implant fixture, using a guide drill, 2.2 mm twist drill, 3.0 mm taper drill, 4.0 mm taper drill, and 6.0 mm ultra-taper drill. A total of 12 implant fixtures of SA, SA + VUV, and SA + VUV + BS, 8.5 mm long with a 3.5 mm diameter, were placed bilaterally with 35 N cm of pre-set insertion torque. Whole bleeding from the gap between the hole and implant fixture was socked in a cotton pellet until 10 min after implant placement, and the weight (g) of the cotton pellet was measured every minute to evaluate the potential of the blood clotting of the implant fixtures. All experimental animals were sacrificed after the surgery by an intravenous overdose of potassium chloride.
