A text-book of dental histology and embryology, including laboratory directions . A transverse section of a root extracted from a young person. The cementum isthin, but is thicker in the grooves on the proximal sides. by the formation of a new layer of cementum, to reattachconnective-tissue fibers in new positions or adjust them tonew directions of strain. The first layer of cementum is formed while the tooth is still in its crypt, but apparently no connective-tissue fibers are calcified into it. This forms the first apparently clear and structureless layer which lies next to the granular 13 1
A text-book of dental histology and embryology, including laboratory directions . A transverse section of a root extracted from a young person. The cementum isthin, but is thicker in the grooves on the proximal sides. by the formation of a new layer of cementum, to reattachconnective-tissue fibers in new positions or adjust them tonew directions of strain. The first layer of cementum is formed while the tooth is still in its crypt, but apparently no connective-tissue fibers are calcified into it. This forms the first apparently clear and structureless layer which lies next to the granular 13 194 THE CEMENTUM layer of Tomes (Fig. 138). Even in the teeth the entirelength of whose roots are formed before they begin to erupt,there is no attachment until some stress comes upon thecrown. The tooth is lying loose in its crypt and can bepicked out with very little force. Bicuspids are often acci-dentally extracted in the extraction of temporary soon as the tooth comes through the gum a new layer Fig. 151. A transverse section of a root from an old person. This root had carried a crownfor many years. The section was cracked and one edge broken. of cementum is formed over the entire root, attaching thefibers to its surface, and as the tooth moves occlusally, layerafter layer is formed. This will be considered again inconnection with the peridental membrane. The Lacunae and Canaliculi.—The lacunae of the cementumcorrespond with the lacunas of bone. They differ from thoseof bone, however, in that they are more irregular in shape,size, position, and relation to the lamellae, and in the number THE CEMENT CORPUSCLES 195 and direction of the canaliculi radiating from them. Inbone the lacunae are fairly regular in shape, the long diameterexceeding the short diameter by about one-third. Sectionscut through their long axis give an oval outline, the length ofwhich is about three times as great as the width. Sectionscut through their short axis give an oval outline, the long
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectteeth, bookyear1912
