## 4 Discussion
### Periodontal Health  
Numerous systematic reviews and meta-analyses indicate a better level of hygiene and periodontal condition in patients treated with CAs [6; 11; 13; 35; 36; 37]. However, each of these publications clearly emphasize that the results should be interpreted with caution due to heterogeneity, different quality, lack of proper blinding procedures or the risk of bias, and that further well-constructed research in this area is needed. The interpreted studies concerned young individuals with healthy periodontitis at the time of the initiation of orthodontic treatment and covered various observation periods; hence, on this basis, it is not possible to draw conclusions about the impact of CA treatment on periodontal health. Similar observations result from the aforementioned literature review, where most studies reveal better periodontal conditions in patients treated with CAs [2; 7; 15; 23; 24; 27; 29; 30]; however, they were measured with different indicators in different observation periods, which does not allow for direct comparison. However, the following meta-analyses demonstrated better periodontal health in people treated with Cas: [PERSON] et al. [13], in a systematic review, analyzed five publications [7; 15; 22; 23; 38], showing that in CA groups, there were greater reductions in PI [7; 15; 22; 23]. GI, PBI, BOP, and PD values were also better in the CA groups [7; 15; 22; 23]. [PERSON] [PERSON] et al. [35], in a meta-analysis involving four studies [7; 15; 25; 26], showed that in a short observation period of 6-12 weeks, patients treated with CAs without additional attachments or adjuncts had better oral health conditions than patients treated with FAs: PI-OR \(-0.58\) 95% CI (\(-0.82\)--\(-0.34\)) \(p\) < 0.001, PD-OR \(-0.42\) 95% CI (\(-0.71\)--\(-0.12\)) \(p\) = 0.006 [28]. However, BOP (OR \(-0.26\) 95% CI (\(-0.77\)-\(0.26\)) \(p\) = 0.33 \(\Gamma^{2}\) = 85.8) and GI (OR \(-0.10\), 95% CI (\(-0.35\)-\(0.15\)) \(p\) = 0.43) values did not differ between the two groups. Similar results were observed in a meta-analysis by [PERSON] and [PERSON] [PERSON] [6] based on eight studies [2; 28; 25; 22; 24; 25; 28; 29; 30]. They showed a slight advantage of CAs over FAs in terms of PI and PD values [6]. The PI values were better in the CA group compared to the FA group during the observation period of 6-9 months (M: \(-0.99\) 95% CI (\(-1.94\)--\(0.03\)) \(p\) = 0.04, \(\Gamma^{2}\) = 99%). During an observation period shorter than 3 months and longer than 12 months, the level of oral hygiene in both groups was comparable. GI values in both groups were comparable, with a slight tendency towards a better gingival condition in the CA group during the observation period \(>12\) months (M: \(-0.46\), 95% CI (\(-1.03\)-\(0.11\)) \(p\) = 0.11, \(\Gamma^{2}\) = 96%). As for the probing depth, both groups were comparable in a period of less than 12 months. In the case of the observation period exceeding one year, one study showed that the pockets in the CA group were shallower (M: \(-0.93\) mm 95% CI (\(-1.16\)--\(0.7\)) \(p\) < 0.0001) [29]. [PERSON] et al. [36] summarized the periodontal status in 29 patients treated with CAs and FAs in an integrative review of eight studies [27; 28; 29; 24; 27; 22; 23; 24]. The analysis of selected studies led to the conclusion that the periodontal condition in people treated with CAs is better, while PI was better in the CA group in most studies. In studies in which there were no major differences between both groups, a greater emphasis was placed on frequent follow-up visits (even every 2 weeks), with the aim to control the level of hygiene as well as to instruct and renovtivate the patients [22; 28; 14]. [PERSON] et al. [39], in an umbrella review including information from four systematic reviews with meta-analyses [6; 11; 40; 41], showed a statistically significant difference between CA and FA treatment groups in terms of PI, GI, SBI and PD in the included papers [36]. However, an analysis of these results led to the conclusion that most had no clinical significance.