Will not eat dog food

We bought our westie 8 weeks ago. She is approximately 3.5 years old. She had not been looked after too well and we had to have her teeth cleaned because of tartar. We believe that she had been fed human food before we got her as it is a real trial to get her to eat dog food. We have tried her with dried food and with tinned meat and dried food. We have never bought her the cheap food but unless I mix it with gravy or some other human food, she would rather starve than eat it. What can I do.

This is a game of chicken and she is winning.
   
Put her food down. Leave it for one hour. After that hour up it comes, whether she has eaten or not.
   
NO TREATS. NO SNACKS. She does not get one morsel until her next scheduled meal.
   
Eventually she will become hungry enough to eat the food she is given.
   
If she whines or cries, TOO BAD. She missed her chance to eat.
   
You have to take control or you will spend the rest of this dog's life catering to its every whim and cooking special meals for it.
   
It's a dog, not a queen, and you are the owner. You call the tune and the tune is, 'dogs eat dog food and humans eat human food.'
   
The sooner you get off this highway, the better.
   
If you really, really, REALLY think you have to give this dog people food or she'll kill herself, then continue to mix it with the dog food but decrease the amount a little bit every day until she is just eating the dog food.
   
But go cold turkey first and see if you can get her to get over herself before trying to wean her slowly.
   
Good luck, I know it's hard to not give in to them but it's for their own good.
   
Human food can give dogs digestive troubles and if you give your dog a good quality dog food, in addition to the better digestion, your dog's poops will be smaller and firmer (which makes for easier scooping) and her farts won't be as frequent or smell as bad (which is for the general good of all).
   
Human food-fed dogs often have a lot of gas and diarrhea and really, who wants those?