Why does my dog’s breath smell?

Bad breath (halitosis) in a dog or cat is usually because of poor dental health.  Occasionally a dog or cat may have good teeth and still have bad breath in which case the diet is usually the cause. This is relatively rare, however, compared to the likelihood of a dental issue.

The process of dental decay in a mouth is a constant and ongoing process that occurs throughout our pets’ lives.  The mouth has excellent defences both in the structure, blood supply and the characteristics of the saliva.  Working against that are bacteria that have evolved to thrive in the mouth.  These bacteria benefit from regular access to food and a consistent environment.  The enamel and gums are resilient, but the bacteria will coat the mouth in a biological film (plaque) that over time calcifies to form tartar.

Tartar is the yellowish substance that adheres to the teeth (colour could also vary from brown, green and grey).  In and of itself it is inactive, but it is a stable source of bacteria that are more resistant to the mouth’s defences.  The most important area for dental disease on a tooth is the pocket between the gums and the tooth known as the sulcus.  Bacteria that grow in this area create inflammation or redness and swelling of the gums known as gingivitis.  Given enough time and inflammation, the gum will recede from the base of the tooth.

Once there has been significant gum recession, the underlying bone into which the tooth is attached will also recede. This exposes the root of the tooth which is not covered in enamel and to which plaque and tartar adhere more easily, accelerating the process.  By this time, most owners will be aware of their dog’s (or cat’s) bad breath. Occasionally the tooth may fall out, but more often the dog will avoid using it and it will continue to decay and become a persistent source of infection and pain.

Ideally, a pet’s teeth should be brushed with an enzymatic toothpaste once daily and the teeth scaled and polished under general anesthetic once every 2-3 years (depending on the speed the tartar returns: different for different breeds and for different individuals).  If no brushing is done, teeth will need to be scaled more frequently.  In the absence of any care, dental disease will progress more rapidly through the course of a pet’s life.  The ongoing dental disease will result in worsening bad breath, a painful mouth and serious impacts on systemic health.

Perhaps just as important however is our tendency to shun an animal with bad dental odour. Dogs are extremely intelligent and have evolved to live with us very closely.  They are much more aware of our moods and how we interact with them than we might expect.  If there is a breakdown in affection and avoidance due to an unpleasant odour, the dog suffers in other aspects.

There is some good news, however.  Even the most severe dental disease and halitosis can be corrected with dental scaling and judicious extraction of diseased teeth.  If a dog has a diseased tooth it is a constant source of pain and infection that the dog avoids using.  By extracting the tooth, the problem is instantly corrected and gums heal incredibly quickly.  Most commercial dog foods (including kibble) do not require extensive chewing to be ingested, so even a dog who has had all teeth extracted rarely has further issues going forward.


Written by Dr. Thompson