Tibbe's breath only gets bad right before it's time for his annual dental cleaning as I brush his teeth regularly besides the annual professional cleanings. Look at your dogs gums and compare them with any of the pictured site's gum/teeth pictures and examine the teeth for brown coloration or coating, dark spots, holes, cracks and the gums for swelling, redness, ulcers, etc. and see the vet if you spot anything that looks bad or suspicious for trouble brewing.
https://www.google.com/search?q=cani...61%3B500%3B416