**7. Conclusions**

In this review, we introduced the pathological significance of periodontal diseases in patients with CKD. Specifically, we showed the increased risks of various pathological conditions, such as diabetes, hypertension, atherosclerosis, liver diseases, and gu<sup>t</sup> microbiota alternation in these patients. Furthermore, in addition to the pathological roles of periodontal diseases in KT patients, we focused on the influence of immunosuppressive drugs on oral health, such as periodontitis, periodontal inflammation, and gingival enlargement. Moreover, the pathological significance and levels of pathogens were compared between patients with CKD and those with KT. Finally, we emphasized the importance of care of oral and periodontal condition to maintain the QoL, prevent complications, and improve survival in patients with CKD and KT. Conversely, a discussion regarding comprehensive preventive strategies of oral health, information on genetic polymorphisms and DNA methylation of oral diseases-related molecules is essential [132]. Based on such information, we sugges<sup>t</sup> that further detailed prospective studies with larger populations and analyses at the molecular level should be performed to clarify the importance of oral health in these patients.

**Funding:** This research was supported by JSPS KAKENHI Grant Number 16K15690 (to Yasuyoshi Miyata).

**Acknowledgments:** We would like to thank Editage (www.editage.jp) for English language editing.

**Conflicts of Interest:** The authors declare no conflicts of interest.
