Excerpt from A Work on Operative Dentistry, Vol. 1 of 2 HE injuries which occur to the hard tissues of the teeth dur ing their development, and which occur to them by accident or disease after they have grown, are peculiar to the enamel and dentin. They have no apparent relation or natural kinship with similar developmental or acquired injuries or diseases of other tissues of the body, except some atrophic injuries to the hair and nails. This is made so by the histological structure of these tissues, in that they have no power of repair and recovery from injuries. The hair, nails, and the continuous growing teeth of a few animals, while having no means of repair of developmental or acquired injuries, dispose of the injured parts by the pro vision for the wearing away Of the substance, and with this the defects. Growth continues to supply new material, and in this negative way may effect a repair. The soft tissue appendages of the teeth, however, as the pulps, peridental membranes, alveolar processes, gums, etc., are developed under Similar histological, physiological and patho logical laws as other soft tissues and bones; and possess similar powers of repair. The developmental injuries are confined to failure in develop ment Of parts of the enamel and dentin because of general sys temic conditions which interfere with nutrition at a time when some particular part of the tooth is being formed, or is growing, and the injury is confined to that part. Other tissues have the power of repair of such injuries later. Since the enamel and dentin do not have this power of self-repair, such injuries in them are permanent. There is a similar failure of self-repair in these tissues when injured by accident or disease after they have been formed, or have grown and completed their develop ment, such as accidental breakage of parts or injuries by erosion or by caries. AS these tissues are not subject to inflammation. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.