Disclaimer: The information provided in this article is not a substitute for professional veterinary help. See your veterinarian for advice suited specifically to your dog.

If you’re like most pet parents, you probably think your dog’s stinky breath is normal, so you ignore it. But doggy breath is an indication of infection that can be deadly if left untreated.

Dental disease is one of the most widespread issues plaguing dogs today—in fact, roughly 90% of dogs will have some degree of dental disease by the time they are just three years old, and often it arises even earlier. PetMD says neglecting dental care is the #2 cause of earlier death in our dogs.

We talked to one of the world’s leading pet dentists, Dr. Brook Niemiec, who is shedding light on why dental disease is so prevalent and what you need to be asking your vet about your pet’s oral health.