Dogs may chatter their teeth when cold or to try to let you know they need to go outside, which you can address easily enough. A few hereditary diseases also cause teeth chattering. Observe your pet closely and consult your vet to ensure the behavior does not indicate a serious problem.
Cold, Excited -- or Just Tiny
The simplest explanation for your dog's chattering teeth is that he is cold. This is particularly common among small dogs, who lose body heat more rapidly than large dogs do. Alternatively, if your dog tends to chatter his teeth when you get home from work, during play or in anticipation of a delicious treat, he may simply be excited, which can manifest as teeth chattering. Stressful situations can also cause a dog's teeth to chatter. Additionally, some small breeds, such as Chihuahuas, Jack Russell terriers and miniature pinschers, have a tendency to chatter their chompers.
Advanced Periodontal Disease
Oral problems – particularly advanced periodontal disease – can cause a dog to chatter his teeth in pain. The chattering may occur anytime but is most common when the tooth is touched. Simply touching your dog's jaw -- especially if the affected tooth attaches to the bottom jaw -- may cause pain, which often leads to chattering teeth. Observe your dog's mouth for signs of problems, such as inflamed gums or broken teeth. Seek treatment for such issues as soon as possible to provide your pet with pain relief and to prevent the problem from worsening.
Multisystem Neuronal Degeneration
Some breeds, such as cocker spaniels, bichon frise and Maltese, can suffer from a condition called multisystem neuronal degeneration. Along with muscle tremors and balance problems, the hereditary disease can cause teeth chattering. The disease most often presents when the dog is around 1 year old; unfortunately, no treatment exists, and the disease is usually fatal. Another hereditary disease -- called shaker syndrome -- causes dogs to experience tremors, which may manifest as chattering teeth. Most common among breeds with white fur, this disorder is not fully understood, and veterinarians often diagnose it by excluding all other possible causes. Veterinarians often prescribe steroids, and sometimes sedatives, to alleviate the symptoms.
Focal Motor Seizures
Grand mal seizures often cause a dog's jaw muscles to tighten, which causes their teeth to chatter. While such seizures are obvious to dog owners, focal motor seizures can also cause chattering. These seizures are less severe than grand mal seizures; they are often brief and cause only minor symptoms. Because they are less severe than grand mal seizures, these partial seizures often go unnoticed. Contact your veterinarian immediately if your dog begins having a seizure or suddenly chattering his teeth.