K.W.
Do your own research and your own experimenting. If you can, find a holistic dentist who is willing to work with you. Most dentists are pretty useless as far as prevention goes, though they're handy for fixing teeth.
The fermented cod liver oil tastes utterly disgusting, in all flavors. I have not met a single person who managed to start taking it regularly. The flavored Nordic Naturals cod liver capsules are chewable and reasonably tasty. I know one person who actually uses them as bribes to get her children to do things! The lemon flavored cod-liver oils can also be used in salads, on popcorn, etc.
I'm doing a combined approach of high quality nutrition and moderately good hygiene and I am finally getting a handle on my tooth decay.
Check out these books:
Kiss Your Dentist Goodbye! (by Ellie Phillips)
Cure Tooth Decay (by Ramiel Nagel)
research "oil pulling"
research the use of ozone in dentistry
Good luck! This is all very individual.