Medically it was proven that in 3 years of eating foods that are digestable the teeth will scar over and start healing and show signs of this by the first year and easily seen by the 3rd year.
Medically it was proven that within 9 years all dental decay would be 100% healed and the person have perfect teeth "IF" they ate properly.
This is why a few see their dental metals and plastics pop out, their teeth are tring to heal after they have cleaned up their act.
Medical proven FACT: No tooth brush has ever stopped tooth decay All decay starts from dirty blood stream and comes from the inside out. I have to believe this because I have seen familys that never use a tooth brush and have perfect super white teeth. I do think brushing is good, as long as no chemicals are used.
The Problem
No one will change their habits that lead to the loss of teethe in the first place.