What is the difference between primary and permanent teeth?

Q: What are the differences between primary and permanent teeth?

A:Primary teeth are Milk teeth, which appear in the mouth at 6-7 months and shed by 11 years. These are 20 in number. Permanent teeth appear at 6-7 years and the last permanent tooth (Wisdom tooth) appears at the age of 17-23 years. Most permanent teeth erupt at the place of milk teeth except few.