The staining on your dogs teeth can be an early warning sign for things to come. I suggest you get them cleaned and (if suggested) have radiographs taken of your dog's teeth. Your dog has to be sedated because, unlike humans, you can't tell a dog, "ok and open wide and stay like that for 30 min." We once had a dog come into the clinic with staining, and the owner declined the cleaning. The next year the dog had some infections in its mouth and again they declined any dental work. In the 3rd year we had to euthanize the dog as its teeth had poisoned its kidneys and given it renal failure. That was an extreme case, but situations like that don't happen all that infrequently.
I brush both of my dogs teeth at home (i started when they were 6 months old to get them used to it) so i haven't had this treatment done myself. However in clinic we do up to 4 dog dentals a week so I can say that most people are satisfied with the cleaning. It is more that just having good looking teeth, it is about your dogs oral care. Pets have teeth too and it is important that people understand that many dogs have to go to the dentist at least once in their life. If you are happy with your vet, you should trust her reccomendations. The last thing she wants to do is bring your dog to harm. Hope this helps.
Kim