There are other options you may like to try before going down the descaling route via GA which are not as intrusive.
If you do not want to give bones (and not all owners can provide them for various reasons just as some dogs cannot cope with them) then you could try fragaria which is a homeopathic pilule (wild strawberry) which can help with tartar. It does not work on all dogs, but you can get it from Dorwest or Hilton Herbs.
Another route is Plaque Off which is a seaweed based supplement which also works on dogs (and humans); something that you have to avoid if your dog has thyroid issues though.
Neither of the above is expensive and should not cause any digestive issues.