ADA: Gum Disease (Periodontal Disease) -
Detection, treatment and, prevention of periodontal diseases, from the American Dental Association.
http://www.ada.org/public/faq/gums.html

eMedicine Health - Gingivitis -
Consumer health resource center providing information on the causes, symptoms, and treatment.
http://www.emedicinehealth.com/articles/20577-1.asp

Gum Disease Information -
 The American Academy of Periodontology's description of periodontal (gum) diseases, including gingivitis and periodontitis.
http://www.perio.org/consumer/2a.html

Gum Disease Information Bureau -
 Advice on diagnosis and treatment of gum disease, gingivitis, periodontitis and mouth ulcers.
http://www.gumdiseaseinfo.co.uk/

MayoClinic.com: Gingivitis -
Symptoms, causes, treatment, and prevention.
http://www.mayoclinic.com/invoke.cfm?id=DS00363

MEDLINEplus Medical Encyclopedia: Gingivitis -
 Illustrations, causes, prevention, and treatment, from the National Library of Medicine.
http://www.nlm.nih.gov/medlineplus/ency/article/001056.htm

NIDCR: Periodontal (Gum) Diseases -
 The National Institute of Dental and Craniofacial Research describes gum disease and presents an overview of risks and treatments.
http://www.nidr.nih.gov/health/newsandhealth/gumDiseasesPub.asp

Periodontal Health - OHSU -
 Overview, symptom and treatment information from Oregon Health and Sciences University.
http://www.ohsuhealth.com/htaz/oralhlth/