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 play a crucial role in helping children chew food and speak properly. These teeth eventually fall out to make way for permanent teeth, which start to appear around age six. Primary teeth are important for maintaining space in the jaw for the permanent teeth and contribute to the overall health and development of a child's mouth.