Primary teeth, also known as baby teeth or deciduous teeth, are the first set of teeth that develop in children. They typically begin to emerge around six months of age and are usually fully formed by age three. There are 20 primary teeth in total, which include incisors, canines, and molars. These teeth play a crucial role in a child's development, aiding in chewing food and helping with speech. Primary teeth also serve as placeholders for the permanent teeth that will replace them later, usually starting around age six and continuing until the early teenage years.