## 4 Discussion  
Several fundamental studies have identified the advantages of ultraviolet irradiation as follows: superhydrophilicity of titanium surfaces, removal of surface hydrocarbons, increased protein binding force, promoted osteoblastic activity, and promoted cell attachment and proliferation [25, 26]. These phenomena are complementary to each other and occur with a close relationship [27]. Ultraviolet treatment can overcome degradation of the bioactivity of titanium implants through increasing surface wettability and initial fibroblast attachment, which has been proven through many studies [18, 26]. However, we did not find any differences in osseointegration at 12 weeks. In addition, a 5% positive difference in BIC between the experimental and the control groups at 4 weeks of healing and a 5% negative difference at 12 weeks suggested that the UV treatment may not clinically help with osseointegration. We also found an average 70% BIC after 12 weeks of observation, which is the typical BIC value according to many other studies [28] and significantly lower than in other studies that reported an average of 98% BIC, superosseointegration, after a four-week period of UV irradiation [29]. This may be because other studies that reported higher percentage of BIC included the highest part of BIC, which is in the cortical compartment, and excluded the bone marrow area in which new bone formation could not be observed. However, in this study, to use the same baseline between the experimental group and the control group, the same consequent five implant threads were measured [24]. This result is reliable and can be strongly supported by other recent studies [30, 31]. [PERSON] et al. noted that low BIC values were observed in both the UV-irradiated and non-irradiated groups, and the results showed no statistically significant differences [30]. [PERSON] et al. also found that osteoblast activity in UV-treated titanium samples is not significantly different from that of untreated samples, which contradicts the recently known effects of photofunctionalization [31]. Many studies were conducted to measure initial stability after implantation [10, 20, 21]. Typically, a Periotest(r) is conducted using PTV, which requires at least 16 strikes with a hitting-type device to verify if the implant can adversely affect the initial stage of stability after implant placement [20]. This can also cause discomfort to patients as they sometimes fail to achieve stable values even after 16 strikes. Figure 5: Comparative Results of weekly measured Implant Stability Test (IST) values. The following is an Oostell(r) that uses ISQ, a device that measures stability using magnetic resonance and requires a magnetized smart peg for measurement [20,21]. This means that the healing abutment must be separated for smart peg adaptation and, in the case of poor implant stability, the implant and healing abutment may simultaneously come out, causing failure [27]. For this reason, more frequent stability measurements may be required in implants with poor initial stability, but the implant failure potential may strain the user [32]. In addition, multiple smart pegs cannot be applied at once by each other's magnetism, which means that multiple implants cannot be measured simultaneously [32]. Lastly, Anycheck(r), which uses the IST value, was used in this study for several reasons, including that multiple implants can be measured at the same time, and the healing abutment does not need to be removed for each measurement [22]. According to the results, the average IST value in all groups showed a moderate decrease after one week of implantation, a rapid increase at two weeks, a peak value at four weeks, and a tendency to maintain peak value from four weeks.