I feed a raw diet and the dental benefits are huge. It's not for everyone, but if you are interested and open to it, it is a very healthy diet.
The first page of this post gives you the information you need to learn more about it.
Are you considering a raw diet?
If you aren't interested in doing a raw diet, you can still get some of the dental benefits by feeding raw meaty bone-in pieces, such as wings, drumsticks, thighs, ribs, etc. in place of a kibble meal. Bullysticks can also be helpful if your dog is a vigorous chewer.
Do not feed cooked bones ever. That includes the smoked bones you get at pet stores. Rawhide is also not advised. The raw soup or marrow bones from the butcher CAN be appropriate, but it depends on your dog. I hesitate to recommend them as they are known to be tooth breakers for some dogs. The best way to clean teeth is with a natural, species appropriate diet.
Expecting kibble to clean teeth is like chewing crackers and then expecting your teeth to be clean. There is NO scrubbing action that is going to clean teeth, this is a myth.
There are also products you can use, such as petzlife oral gel which is supposed to be good at dissolving tartar. I haven't used these products but have heard good reviews.
I would also advise you to stay away from 'greenies' and other dental treats. There have been cases of impactions and blockages from these products. They are just hardened corn starch.
A natural diet is best, in my opinion.
Here's a picture of Brody's teeth. He is almost 2. He's never had a dental and has never had a speck of build up on his teeth.