## 4 Discussion
The hydrophilic surface is regarded to osteointegrate faster than other commonly used types of surfaces, including sand blasted and acid etched. [PERSON] et al. reported that hydrophilic surface implants gain a stability of 70 ISQ in less than five weeks which means that it is 2.24 times faster than implants treated with sand blasting and acid etching [20]. The hydrophilic surface implants modified with hydroxyl ion have been assessed for primary and secondary stability only in two other studies to date. Primary stability in the mentioned studies' plants amounted to 57.3 (\(\pm\)7.4) ISQ and raised to 71.3 (\(\pm\)8.2) ISQ while loading [28]. The above-mentioned studies mostly focused on measuring the stability of conventionally loaded implants. An evaluation of the obtained results of MBL shows that they do not deviate from the established norm, according to which MBL should not be greater than 1.5 mm in the first year and then 0.1 mm in each following year. It is important to note that some researchers claim that original remodeling of the alveolar process occurs after implant loading with the aim of restoring biological width [29; 30; 31; 32; 33]. However, the condition of the surrounding implant soft tissues seems to play a role in this process. [PERSON] et al. reported significantly lower MBL in a one-year observation when the implant surrounding soft tissue was thicker than 2 mm. The average MBL level in those cases was 0.21 mm and is comparable to our results [29]. The lowest (0.22 \(\pm\) 0.49 mm) MBL level of early loaded hydrophilic implants with the same, as presented in the following manuscript, observation period (12 months), to date, has been reported by [PERSON] et al. [30]. This finding of a low MBL was accompanied by high stability values at all time points (above 71 ISQ) and, similar to the presented study findings, (Figure 4) wide implants showed statistically higher stability values than narrow implants. On the contrary, much higher MBL levels than those found in our study for hydrophilic implants were reported by [PERSON] et al. (0.98 \(\pm\) 0.61 mm) in 13 months of follow-up, and by [PERSON] et al. (0.99 \(\pm\) 0.29) in 12 months of follow-up [31; 32]. In the literature, there are relatively few studies concerning the effects of early loading and changes in stability in connection with MBL. [PERSON] et al. were among the first who reported the results of studies concerning 68 early-loaded maxillary implants. The value of the average baseline ISQ parameters was 60.1, whereas the implant survival rate was 93.4% and the MBL level was 1.3 \(\pm\) 0.6 mm at a 12-month follow-up observation [33]. [PERSON] et al. assessed oxidized-surface implants that were loaded for the period ranging from a few days to 16 days. They achieved an overall success rate of 98.1% and the averaged MBL index was 1.1 mm at a 12-month follow-up observation. In contrast, the ISQ index increased from 63.3 (\(\pm\)6.1) to 66.8 (\(\pm\)5.6) after 12 months [24]. The effect of early loading relative to conventional loading on bone tissue levels (without linking with primary stability levels) was also previously studied in other papers. [PERSON] et al. assessed immediately loaded implants with a diameter of 3 mm, obtaining the MBL level of 0.85 \(\pm\) 0.71 mm at a 36-month follow-up observation [34]. In studies concerning early-loaded implants (three weeks), [PERSON] proved efficacy comparable to immediate loading (with a loss of one implant in both groups) at a 12-month follow-up observation. However, a higher average MBL was found in the group of implants loaded after three weeks (0.390 \(\pm\) 0.840 mm) when compared to immediately-loaded implants (0.120 \(\pm\) 0.230 mm), with no statistically significant differences between those groups [35]. Other authors report that there is no effect of implant loading time on marginal bone loss. MBL levels in the mentioned studies ranged from 0 to 1.32 mm in longtime observation [36; 37; 38; 39].