Years ago I switched to brushing with baking soda and salt, and my teeth have basically stopped degenerating. Bar soap is good too, for removing acid-producing bacteria, but I don't like the aftertaste of some soaps.
[1] http://www.fixyourteeth.org/
Just yesterday my brother & his wife were commenting on how good my 8-year old dog's teeth are. They've never been professionally cleaned. When she was a puppy, we fed her raw chicken with bones. When she got to be full sized this was too expensive, so she now she eats dog food. I think the main reason she has such good teeth now is because she had adequate calcium and other nutrients when her teeth were forming.
Humans who have perfectly healthy and well taken care of teeth still go to the dentist, and for dogs it is no different. You should still be getting her once a year!
There are more issues than not which could be happening that are not visible to the untrained eye.
http://www.vetblog.net/2013/07/dog.swallowed.chicken.bone.pr...
http://keepthetailwagging.com/dont-panic-when-a-dog-eats-a-c...
As I said elsewhere, she now eats regular dog food. When I'm visiting, I'll cut the cartilage off the end of a cooked chicken bone and give that to her. Sometimes she still helps herself to whatever bones she finds, and she hasn't had any problems.
Size might be a factor - she is about 75 pounds.
My dad's previous dog ate corn cobs. After years of this, a corn cob got stuck in his throat, leading to a big vet bill, so our dogs don't get corn cobs anymore.
Interestingly the growth rate of modern meat chickens is limited to bone mineralisation rate. If you breed a chicken with faster growth rates (which you can do) they end up with broken legs as the bone can’t support the weight of the bird [1].
Most dogs do have calculus in their mouth even if there is not active decay. There is also subgingival calculus (below the gum line, not visible to the human eye). Taking your dog to annual vet visits is important because they can help diagnose dental issues.
Lots of dog foods contains sugars, and even more contain a ton of more complex carbs, which the bacteria do still feed on. This is why species appropriate raw fed dogs don't have calculus, they don't eat carbs.
The link provided argues otherwise:
"Bacteria cannot damage the enamel (calcium hydroxy phosphate). There is no such thing as decay of the enamel since bacteria require carbon and hydrogen to live. Billions of human and animal remains show teeth and bones are resistant to earth-bound organisms."
and
"acids alone eat the enamel..."
If you don't mind spending a few dollars, flavored tooth soaps are carried by most natural food stores.
If one is concerned about rubbing their teeth away, baking soda and salt will rapidly dissolve in the saliva.