Principles and practice of operative dentistry . demonstration is more difficult and requires theconstruction of a somewhat delicate instrument. The record or odonto-gram made by this instrument shows the height and breadth of theridges and the depth and width of the furrows or depressions and theirnumber in a given space. The measurements are, however, greatly magni-fied by reason of the length of the recording arm or lever. Pickerill presents the following hypothesis to account for the presenceof these lines in the enamel surface. * All varieties of imbrications andstriations are to be regar
Principles and practice of operative dentistry . demonstration is more difficult and requires theconstruction of a somewhat delicate instrument. The record or odonto-gram made by this instrument shows the height and breadth of theridges and the depth and width of the furrows or depressions and theirnumber in a given space. The measurements are, however, greatly magni-fied by reason of the length of the recording arm or lever. Pickerill presents the following hypothesis to account for the presenceof these lines in the enamel surface. * All varieties of imbrications andstriations are to be regarded as checks in the secretive function of theameloblasts. As regards the nature of the check to the functions of the ameloblastshe believes it is due to the pressure of the long walls of the crypt inwhich the tooth is developing—i. e., the resultant of two forces ofevolution. 1. The hereditary tendency of the ameloblasts to continue functioningto a certain definite extent. * Prevention of Dental Caries and Oral Sepsis, pp. 50, 51, 52 (1912).. Showing varicosed enamel-rods. (After Dr. J. Leon Williams.)
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectdentist, bookyear1920
