Dental formula is the arrangement of different types of teeth in an oral cavity. Four types of teeth in a human jaw are Incisors, Canines, Premolars and Molars.Dental formula of a human child is 212/212Incisors emerge when the baby is 6 months old. Canines grow when the baby is 20 months old. First molars emerge out between the age of 13 to 19 months. Second molars emerge out at the age of 24 months. Premolars are not at all the baby teeth. They are said to be permanent teeth.Human infant is the child whose age is below 12 months. So infants have only incisors in both the jaws.