Pets often injure their teeth. Frequently they break their teeth and expose the pulp (nerve). These teeth are painful and always become infected. A discolored tooth is also an injured tooth due to bruising inside the tooth. These teeth are often non-vital. Broken and discolored teeth can frequently be salvaged by an endodontic (root canal) procedure. The only other option is extraction. The larger and more important the tooth, the greater the need for root canal therapy.