A text-book of dental histology and embryology, including laboratory directions . The preparation of the gingival wall of the cavity shown in Fig. 65 Fig. 62 is a similar section from a molar. After choppingaway the occlusal wall until the cavity has been extendedto the point of greatest convexity of the surface, the wall isseen to be in the condition shown in Fig. 63. Near the sur-face some rods have broken across, and near the dento-enameljunction the same thing has happened, but in the rest of thedistance the cleavage has followed the enamel rod inclination of the wall is incr
A text-book of dental histology and embryology, including laboratory directions . The preparation of the gingival wall of the cavity shown in Fig. 65 Fig. 62 is a similar section from a molar. After choppingaway the occlusal wall until the cavity has been extendedto the point of greatest convexity of the surface, the wall isseen to be in the condition shown in Fig. 63. Near the sur-face some rods have broken across, and near the dento-enameljunction the same thing has happened, but in the rest of thedistance the cleavage has followed the enamel rod inclination of the wall is increased by planing untilthis roughness has been removed, and then the cavosurfaceangle is bevelled to support the marginal rods, and prepara-tion is complete, as shown in Fig. 64. GINGIVAL THIRD CAVITIES 105 Fig. 65 shows a cavity in the lingual pit of a superiorlateral incisor. Caries has undermined the enamel to a Fig. 67. The preparation of the cavity shown in Fig. 65. 106 PREPARATION OF TYPICAL ENAMEL WALLS considerable extent, and the cavity will have to be largerthan would otherwise have been necessary. Placing thechisel close to the occlusal margin, as indicated, the enamelis chipped away in that direction and around the circum-ference. On the lingual wall the chisel may be reversedand used with a pulling motion, like a hoe. In this waythe undermined enamel is chipped away and the tip ofthe marginal ridge removed. The wall is then planed intothe horizontal plane and the cavosurface angle 66 shows the structure of the gingival wall, and Fig. 67the relation to the crown. CHAPTER X STRUCTURAL DEFECTS IN THE ENAMEL The formation of enamel begins at the dento-enameljunction, and the tissue is laid down from within outward,so that the enamel in contact with the dentine is formedfirst and the surface of the crown last. Enamel formationbegins at several points, for each crown, the exact numbe
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectteeth, bookyear1912
