Good oral hygiene and regular dental visits help prevent gingivitis.  Untreated gingivitis will most likely progress into periodontitis, a more significant and more damaging form of gum disease.  Periodontitis is a significant worsening of the supporting structure that helps support the root of a tooth and is more difficult to treat than gingivitis.  Untreated periodontitis can lead to painful infections, loose teeth, and eventual loss of teeth.