Sucking is a normal reflex of a baby. Simply put, it relaxes and comforts them. The need for sucking usually comes to an end between the age of two or three. But for some, prolonged and vigorous sucking after the age of four can cause problems with normal dental development. If you are concerned your child’s sucking may cause dental problems, visit your dentist and discuss the matter. He or she can tell you the best method for weaning your child from the habit.