Eruption of human teeth

Abstract

HE process of eruption of human teeth has been of considerable interest to man since early times. The spectacular nature of the dentition, which is so different from any other phenomenon in human growth, and the regularity with which each tooth appears led even the ancient observers to consider the dates of eruption as landmarks for the chronology of man. A review of the literature revealed a number of investigations on the chronology of teeth. The data reported varied from simple age ranges during which a tooth might emerge to more definitive standards. In contrast to permanent dentition, the standards for the emergence of deciduous dentitions were relatively few and not sufficiently established. The relative lack of information concerning the deciduous dentition was probably due to difficulty in collecting data on children of young enough age that they seldom visit the dentist. Most of the statistics have been derived from cross-sectional material. There were a few exceptions, however, in which longitudinal material was used (the works of Doering and Allen1 and Robinow and associate9 on the deciduous dentition and of Stones and colleagues3 and Fulton and Price4 on the permanent dentition) . It was apparent from a study of these as well as several other reports that no general agreement existed concerning the norms for the ages of tooth eruption. All of the authors, however, unanimously agreed that a wide margin of variation existed in different tooth pairs, individuals, and population groups. One question which did not receive sufficient attention was the extent to which alterations in the range of variation with age might be expected. We know, for example, that at the age of 6 years a boy may have no permanent teeth, or as many as twelve may have erupted. The outstanding question, then, is : “Should one expect nearly the same range of variation at all ages, or would it be different ? ” If the range is more at some ages and less at others, then it may be easier to spot a child suspected of growth disturbance. A child with impairment in the developmental processes will stand out more prominently at an age when the range of variation in the eruption of teeth is minimal than at an age when it is maximal; thus, the chances of isolating pathologic cases is increased. Of course, it should be remembered that retardation or precocity of