Vitamin C builds collagen and elastin. Subclinical scurvy and weak/spongy gums and gum bleeding can be caused by lack of vitamin C. My gums and upper palette are stronger and don't get torn up as much when I eat chips since I've been using this swish n spit:
1/4 teaspoon ascorbic acid (vitamin C)
1/4 teaspoon sodium bicarbonate (baking soda)
2 tablespoons water
I tested this formula a dozen times to be alkaline with equal amounts of baking soda and ascorbic acid, so the acids are 100% neutralized and won't dissolve teeth. pH is around 8. Swish for as long as you can, or whenever. Right before bed is good too.