"Next up, comfrey root helps with tooth decay because of its ability to amp up bone, tissue, and tooth growth. Blend 1 square inch of comfrey root with 2 tablespoons of water and swish the liquid in your mouth.
Fat soluble vitamins like vitamins A, D, E, and K are good for regrowth. Curtis Aiken of Co-Inside says that the following foods are good for regrowing your teeth: Celtic or Pink Himalayan salt, fermented foods, sea vegetables, soaked and sprouted nuts, coconut oil, greens,
See entire article @ Naturally Savvy
Comfrey Root - Read because Comfrey is dangerous when swallowed.
"Comfrey is a plant. Even though this plant contains poisonous chemicals called pyrrolizidine alkaloids (PAs), the leaf, root, and root-like stem (rhizome) are used to make medicine. The amount of PAs found in comfrey changes according to the time of harvesting and the age of the plant. The roots have 10 times higher amounts of PAs than the leaves. Some products labeled “common comfrey” or Symphytum officinale actually contain the more poisonous “prickly comfrey” (Symphytum asperum) or “Russian comfrey” (Symphytum x uplandicum) species.
Comfrey is used as a tea for upset stomach, ulcers, heavy menstrual periods, diarrhea, bloody urine, persistent cough, painful breathing (pleuritis), bronchitis, cancer, and chest pain (angina). It is also used as a gargle for gum disease and sore throat.
Comfrey is applied to the skin for ulcers, wounds, joint inflammation, bruises, rheumatoid arthritis, swollen veins (phlebitis), gout, and fractures.
How does it work?
The chemicals in comfrey might have a healing effect and reduce inflammation when applied to the skin. However, comfrey contains toxic chemicals that can be absorbed through the skin...
Comfrey is POSSIBLY SAFE for most people when applied to unbroken skin in small amounts for less than 10 days. It’s important to remember that the poisonous chemicals in comfrey can pass through the skin. Absorption of these chemicals increases if the skin is broken or if large amounts are applied.
Comfrey is LIKELY UNSAFE for anyone when taken by mouth. It contains chemicals (pyrrolizidine alkaloids, PAs) that can cause liver damage, lung damage, and cancer. The FDA has recommended removal of oral comfrey products from the market."
See more info @ WebMD