Baby teeth are very important to your child's health and development. They help him or her chew, speak and smile. They also hold space in the jaws for permanent teeth that are growing under the gums. What is the purpose of milk teeth? These "first teeth" are necessary for a child to chew and speak. But baby teeth serve another very important purpose--they save space for the child's future permanent teeth. A baby tooth usually remains in the child's mouth until a permanent tooth underneath it is ready to emerge through the gums.