Teething describes the physiologic process of tooth eruption through the gums of the mouth.
Teething normally begins between the 6th and 8th month of life. Further tooth eruption occurs periodically until all 20 teeth of infancy and childhood, or deciduous teeth, are in place. All the deciduous teeth are normally in place by the 30th month of life. The 2 lower incisors usually erupt first followed by the 2 lower incisors, upper lateral incisors, lower molar, upper molar, lower canine, upper canine, lower lateral molar, and finally the upper lateral molar. The discomfort that results from teething is due to the pressure exerted on the tissue in the mouth, called the periodontal membrane, as the teeth erupt.