When I adopted Gracie some of her teeth were stained with yellowish-brown marks. After a few months of regular, home dental care they looked much better but Gracie's vet said some of the stains would never go away.
The above photo shows the tools I use to help keep my dog's teeth clean. Gracie's veterinarians always say her teeth look clean. None of them ever recommended a professional cleaning!
I try to brush Gracie's teeth at least once or twice a week. I use a Braun electric toothbrush but I don't turn it on. Soon after buying it I found out Gracie did not like the buzzing sound and movement of the brush! I just use it as a manual toothbrush. It's excellent. The head is small enough for me to reach all her teeth without causing her too much discomfort. Also, the heads can be cleaned easily and replaced.
I use CET Enzymatic Toothpaste for Dogs and Cats, in poultry flavor. A vet recommended it to me several years ago and Gracie seems to enjoy the taste.
Every once in a while, when needed, I use the metal dental instrument pictured above to scrape plaque build-up off Gracie's teeth. Some vets and animal care "experts" advise against anyone but a veterinary professional doing this. They claim most dog owners will not do it properly, scratch the tooth surface and cause more plaque build-up. If I see plaque build-up on Gracie's teeth I scrape and wipe it away as gently as I can. We haven't had any problems so far!