Can a root canal stop gum bleeding on all my gums? for quite a few years, even when flossing daily, my gums, all over my mouth, bled quite easily. it only took 1 or 2 days of missed flossing for bleeding to become worse?

Bleeding gums: Sign of periodontal (gum/bone) disease that has gone untreated for what sounds like many years. Periodontal disease is an infection that can severely damage other organ system. You need to see a specialist Periodontist now. Please don't ignore the red flag signals your body is sending you.

Root Canal Therapy: A necrotic nerve may cause a localized endo-perio problem around that specific tooth. If all of your gingiva bleed, then you at a minimum have gingivitis, possibly periodontitis. Are currently under the care of a dentist for regular cleanings and maintenance? If not, time to make an appointment. If so, have yourself evaluated for periodontal care. Flossing/brushing alone doesn't prevent disease.