Similarly to humans, kittens have a set of teeth that fall out and are replaced by permanent teeth. Kittens have temporary "primary" teeth that are replaced starting when the kitten is three or four months old.
Kittens' primary teeth are replaced by permanent teeth. While the permanent teeth grow, kittens feel discomfort and an increased urge to chew. Occasionally, a primary tooth does not fall out before the permanent tooth grows into place. A veterinarian extracts the primary tooth while the kitten is under anesthesia. If the primary tooth is not extracted early enough, the permanent tooth remains in the incorrect position.