A healthy dog's gums are either pink, black or spotted, according to the American Kennel Club. However, black spots that appear along the surface of the gum could be cavities, cautions the Massachusetts Society for the Prevention of Cruelty to Animals (MSPCA). The black color along the gum line is a tooth's root protruding that needs to be treated immediately to prevent further health problems. In most cases, veterinarians simply remove teeth with cavities.
While most dogs have pink gums resembling those of humans, black pigmentation is not uncommon in certain breeds. If the color of a dog's gums changes suddenly, however, this indicates the dog is possibly suffering from a dental trauma. Pawing at the face or increased salivation can also be signs of oral discomfort in your pet, according to the MSPA. In the event of such a situation, contact a veterinarian immediately for assessment of the problem and treatment.
The College of Veterinary Medicine at the University of Illinois recommends owners regularly check their dogs' gum color for health. It states that gums need to feel firm to the touch, and the color remain unchanged. If the dog reacts poorly to having pressure placed along the gums, this is indicative of a potentially serious dental issue.