My poor dog's breath....?

She is 6 years old (Maltese) and when I got her I knew nothing about taking care of a dog. I didn't know that wet food and people food was bad for her teeth, and the first couple years I had her, that's all I fed her. Now of course, I know that wetfood and people food causes tarter build-up and decay in dogs, and I only give her all natural dry food now. But I'm afraid it's too late; her breath is terrible!! Poor thing, she's so cute but when she gets close, her breath is too funky and she isn't cute anymore:( I believe her diet, now, supports it from getting any worse. Unfortunetly it cannot reverse the damage though. Is there anything I can do, aside from having the vet sedate her and sc all that junk off, that can help my dog's breath?