Medical Diseases of Infancy and Childhood (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1900 Excerpt: ...of the alveolar process of each upper jaw. In sucking, the tongue perhaps presses back on these two pairs of points, but they are more probably injured during the process of cleaning the mouth, when the lower jaw is depressed and the mucous membrane put on the stretch. Symmetrical shallow ulcere may thus be produced over these parts, and such ulcers are known by the name of Bednar's aphthae. Dentition.--As has been well said,1 "Dentition is a continuous physiological process commencing in early foetal life and terminating with the appearance of the wisdom teeth at the age of from eighteen to twenty-two, or even twenty-five years; but, whilst dentition may be said to be continuous, the eruption of the teeth is an intermittent process, the teeth appearing in groups and at certain intervals of time." The eruption of the milk, or temporary, teeth begins at the sixth or seventh month and ends about the third year. The eruption of the permanent teeth begins in the sixth year and ends with the cutting of the third molar, at some period between eighteen and twentyfour years as a ride. The first dentition is divisible into five periods: --(1) Sixth to Eighth month Two lower central incisors. (2) Ninth to Tenth month Two upper central incisors. Two upper lateral incisors. (3) Twelfth to Fourteenth month Two upper anterior molars. Two lower lateral incisors. Two lower anterior molars. (4) Sixteenth to Twenty-second month Four canines. (5) Eighteenth to Thirty-sixth month Four posterior molars. This is the normal sequence, but variations are common. The upper central incisors may appear before the lower; the canines may appear earlier or later than usual, and similar irregularities may be observed in other teeth. Occasionally dentition begins very early, and c...