Volume 1

A work on operative dentistry ... / by G.V. Black ; with revision by Arthur D. Black.

  • Greene Vardiman Black
Date:
1924
Catalogue details

Licence: Public Domain Mark

Credit: A work on operative dentistry ... / by G.V. Black ; with revision by Arthur D. Black. Source: Wellcome Collection.

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    rendering them useless for this purpose. Figures 27, 28 and 29, with their descriptions, serve, however, to illustrate the condi¬ tion of the tissue injuries fairly well, though neither of them are of the severer forms of atrophy. Figure 27 particularly shows the line of interglobular spaces in the dentin extending across the occlusal surface and dipping down gingivally along the axial portions of the dento-enamel junction. This figure also shows well the shortening of the crown between the pulp of the tooth and the occlusal surface. From the position of these zones of injury, it will be realized, from a careful study of the lines of the injury to the dentin, that the total shortening of the crown of the tooth is between the pulp and the occlusal surface in the molars. It is also between the pulp and the incisal edge, where it occurs in the incisors and cuspids. This is the reason that pulps are so frequently exposed in the preparation of cavities in these teeth. Dentists generally have not understood that the pulps were so close to the surface. When it is realized that these sheets of interglobular spaces, of which the zone of injury in the dentin showing in Figure 27 and in Figure 29 is a section spread through the entire area of the crown of the tooth, form¬ ing openings through which microorganisms may readily grow, it will be understood why it is so difficult to prevent the destruc¬ tion of these teeth by caries. It will also be understood how decay may quickly undermine the entire enamel cap, allowing it to fall away, exposing a blackened stump of dentin in all of the central portion with jagged enamel upon its margins, with decay persisting around the circumference where the line, or sheet, of interglobular spaces dips to the gingival near the dento- enamel junction. In the child, one is prohibited from forming a cavity of such depth as required to hold such a broad filling because of the nearness of the pulp of the tooth. The grave significance of this lies in the fact that caries beginning in the imperfections of the occlusal surface quickly reaches this zone of interglobular spaces and spreads rapidly through it, undermining and destroying the whole occlusal por¬ tion of the tooth. It often happens that the whole of this has been swept away so quickly that the area is uncovered before decay has proceeded further toward the pulp. The decaying area is then fully exposed to the fluids of the mouth, and the progress of the caries is arrested. In this case, the tooth remains as a blackened stump that soon rises in its alveolus and occludes with its fellow, which is generally in a similar condition, and both do good service. More often, however, decay continues in that portion of the zone of injury referred to, that dips under the strong enamel around the margins of the crown. Being thus
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