But it doesn't seem to bother my pet!

This is a common observation by pet owners when problems are found in their pet’s mouth.  Yes, the fractured tooth or inflamed gums hurt.  It’s just that animals evolved masking their discomfort.  If an animal displayed weakness from an illness a predator would consume them for lunch. Our companion animals evolved as pack animals which required them to mask any problems...

Red gums and bad breath
 

The number one problem companion animals experience in their mouths is periodontal disease.  This is a progressive disease and once diagnosed the goal is to control it while preserving the teeth with which they eat.  The usual presentation is a pet with halitosis. When the mouth is examined typically there is significant plaque and calculus (tartar) on the crowns.

Fractured teeth, the silent disease
 

Fractured teeth represent a silent disease.  Pets do not grab their cell phones and call their dentist when this happens – people do.  As discussed, pets mask their discomfort.  In the case of fractured teeth with pulp (nerve exposure) the tooth is painful for a few days then as the pulp dies the acute pain subsides.  This give the pet owner the false sense that everything is fine.