Rottin dog teeth

Question
My dogs teeth are starting to rot (green), shes only seven and suppose to live for 20 years. I'm not quite sure what makes her teeth rot considering I've been feeding her things to clean her teeth, I use to brush them regularly but I started slacking after the vet said there was nt much n eed to, and dont feed her junk food. I started noticing my parents and friends have been feeding her whatever they are eating, and I'vfe been telling them not too. Now I'm worried about her teeth and if they can be saved. What can I do to save her teeth and what food would your recommend?

Answer
For dogs that chew their food, a dry kibble helps with the teeth.  There is a product, Science Diet T/D that comes in large pieces even a lab would have to chew.  Ask your vet about it.  

Getting the rest of the family to knock off the snacks is a tough people problem.  How is her breath?  Point out they are making it worse.