https://www.bing.com/videos/search?q=periodontal+disease+video&qpvt=periodontal+disease+video&view=detail&mid=6309824462C735AE4E8F6309824462C735AE4E8F&&FORM=VDRVRV
https://www.mayoclinic.org/healthy-lifestyle/adult-health/in-depth/dental/art-20047475
http://www.deardoctor.com/dental-videos/