Gingivitis is a common and mild form of gum disease that causes irritation, redness, and swelling of the gums. It occurs when plaque, a sticky film of bacteria, builds up on the teeth and irritates the surrounding gum tissue. If not treated, gingivitis can progress to more serious gum diseases, leading to tooth loss. The primary symptoms of gingivitis include swollen gums, bleeding during brushing or flossing, and bad breath. Good oral hygiene practices, such as regular brushing, flossing, and dental check-ups, can help prevent and treat gingivitis effectively.