When it Starts
Between 4 and 6 months of age, teeth begin pushing through sensitive gum tissue. As a result, your baby will likely drool more and want to chew on anything near his mouth. The first tooth, often a front bottom one, typically erupts at about 7 months, though getting a first tooth as late as 15 months is still normal, says Bill Stratbucker, M.D., a pediatrician at Helen DeVos Children's Hospital in Grand Rapids, Mich., and an assistant professor of pediatrics at Michigan State University. A full set of 20 baby teeth is generally in by 2 1/2 years.