My dog is 15 year old dalmatian she is quite fit though takes tablets for arthritis and several months ago had an inner brain infection which caused her head to tilt she seems to have recovered from this and her head is not tilting but more recently her teeth have started chaatering and this is not just in the cold weather. It lasts for seconds but happens regularly throughout the day. Can you tell me what might be the cause I am wondering if it is something to do with her nervous system as with the brain infection she had.

My male dog's teeth chattered when he caught a scent. My current female's teeth have started to chatter for reasons unknown, and she is about 11 or 12 (age is a guess). That's all I know. It doesn't worry me. Think of how long your dog's snout is and how far back the 'hinge' is. Lots of room to chatter. In an old dog it might just be the equivalent of a tic that many of us get around our eyes - a muscle that is contracting many times a minute, from fatigue.