**Preface to "Prevention and Treatment of Periodontitis"**

When I received an invitation from *J Clin Med* to be the guest editor, I was wondering whether to accept it, but as a result of accepting the role of guest editor together with Professor Kenichi Imai, Nihon University School of Dentistry, 13 papers were included in this book. I am very happy to be able to do this. I would like to thank all the authors for their cooperation.

Yorimasa Ogata on behalf of:

> **Yorimasa Ogata, Kenichi Imai** *Editors*
