There is a product called Novamin that can help remineralize teeth, currently owned by GSK. They took the competition out of the marketplace, and AFAIK only pu

There is a product called Novamin that can help remineralize teeth, currently owned by GSK. They took the competition out of the marketplace, and AFAIK only put it in certain "Sensodyne Repair & Protect" toothpastes, which also contain fluoride; unfortunately it isn't available in USA, but is available in Canada, Thailand, and China (and probably other places also, that's just where I've purchased it). Another source is SHY-NM toothpaste which is sold only in India. One can brush with these toothpastes, or use a dental tray to soak the teeth in Novamin. Above age 35 or so, rather than direct dental caries, the bigger risk for many people is receding gums (gingival recession), which also leads to tooth decay, hot/cold sensitivity, tooth loss, infection, and so on. To try and prevent this, people go to their dentist for scaling and root planing ("conventional periodontal therapy"), which are fancy terms for what is, to me, medieval treatment -- scraping the teeth with metal instruments that readily damage the enamel and dentin. I believe Periogen is a far superior alternative, which is administered using a waterpik and is able to reach significantly below the gumline. Periogen dissolves dental calculus chemically, without the risk of damage that comes with the instruments used in conventional periodontal therapy. Another treatment that promotes healthy gums and discourages tooth decay are probiotic lozenges; the exact formulation differs from brand to brand, but in general the idea is to replenish the microbial colonies in the mouth with species that are helpful rather than harmful. As far as I can tell, the simplest and most effective preventative measure against cavities is to vigorously wash the mouth out with water after eating or drinking anything, every time, no exceptions.