Let’s talk about Cat Teeth: At 8 weeks of age, your kitten will have all their baby teeth; Incisors, Canines and Molars. At 3.5 to 4 months of age, the permanent adult teeth will start coming in over the baby teeth. By 6 months, your cat will have all of their shiny white adult teeth. Teeth may start to dull around the 2 year mark.