Order and age of eruption for the deciduous dentition.

Presently available research literature includes no less than a score of North American studies pertaining to the time and sequence of eruption of the primary or "'milk" teeth. For only about one-sixth of these studies is the medium of original report a dental periodical, the remaining five-sixths are in anthropologi-cal, biological, child development, medical (mainly pediatric) and psychological publications. It is a major objective of this paper to bring together these widely scattered reports and make their contents more readily accessible to members of the dental profession. A second major objective of the paper is that of presenting an epitome of research knowledge concerning the age and order of eruption of deciduous teeth in North American children. This, of course, presupposes a systematic and comprehensive integration of the materials from different studies. The two objectives determine the two parts of the paper: The first-colliga-tion-is carried out under the caption "Presentation of Research Materials" and the second-synthesis-under the caption "Generalizations." There are incorporated in both parts the findings from two previously unpublished investigations. As a point of departure, reference may be made to a "Course of lectures on dentition and its derangements" published by Jacobi (9) in 1860. The materials in these lectures pertaining to eruption of the deciduous teeth were drawn entirely from European studies. Minot (13), in 1873, wrote a paper "On the primary dentition of children" which included statements relating to the order and age of eruption based upon his "own experience." On eruption of the first tooth, Minot stated: "Judging from my own observation, I should put six and a half months as the average date of the appearance of the first tooth" (13, p. 9). The usual sequence of eruption for the full complement of deciduous teeth was given as follows: The "two lower central incisors" at 61 to 7 months; "The four upper incisors, of which the two central ones are the first to appear," at 9 to 10' months; the "upper anterior molars," lower lateral incisors, and "lower anterior molars"-in this order-at 121 to 14 months; "the four canines" at 18 to 21 months; and "the four posterior molars" at 26 to 30 months. At the 1876 annual meeting of the American Dental Association, McQuillen "made a verbal report on the order of eruption of the deciduous teeth" (11, p. 483). After commenting that instances were on record of infants "having been born with …