I always add canned to kibble...when I feed kibble.
Canned food is very good for your dog, and as Mordy mentioned before, it's just a myth that it ruins teeth. Low quality foods of any sort with added sugar or poor ingredients are what ruin teeth (or dogs that pick up and carry huge rocks
- that ruins teeth as well. Canned is not as processed as kibble, it's easy to keep a food more natural through the canning process.
My dogs have fantastic teeth, and by adding canned I know they are getting extra water in thier diets. I never know if they are drinking enough from the water buckets...its less stress on the kidneys.
My oldest Newf is going to be 11 soon, her teeth are pearly white and have never been cleaned. She has been fed canned, canned mixed with kibble, raw, home prepared, scraps etc. I think it's the variety that has kept her in tip top health.