An article in DVM Newsmagazine cites research showing that cats that
develop painful «neck lesions» (dental
cavities at the gum line; also called Feline Odontoclastic Resorptive Lesions, or FORLs) have significantly higher blood levels of Vitamin D than cats who don't.
As a general rule, teeth that have fractured through to the dentine or pulp
cavity (affecting the nerve and blood supply) are likely to need extraction as the tooth will be
painful and it will be at risk of
developing an infection and tooth root abscess.