A few statistics:

• Kittens have their first 26 "milk" or deciduous teeth at 2 to 3 weeks of age. Their 30 permanent teeth begin erupting around 3 months. 
• Cats have the fewest teeth of any common domestic mammal.
• Puppies develop their deciduous teeth at 2 weeks of age, with their 42 permanent teeth starting to appear at 3 months.