A text-book of dental histology and embryology, including laboratory directions . gt; | . --. • * ? ? AWl-U-M lllllllill • //? . - ^*j /^M^fcf A section showing compound curves near the dento-enamel junction. (About 80 X ) The Dentinal Tubules in the Root Portion.—In the rootportion of the dentine the tubules ordinarily show only thesecondary curves, their general direction being at right anglesto the axis of the pulp canal. Throughout their course theygive off an enormous number of very fine branches extendingfrom tubule to tubule. These are so numerous that insuitably prepared sections
A text-book of dental histology and embryology, including laboratory directions . gt; | . --. • * ? ? AWl-U-M lllllllill • //? . - ^*j /^M^fcf A section showing compound curves near the dento-enamel junction. (About 80 X ) The Dentinal Tubules in the Root Portion.—In the rootportion of the dentine the tubules ordinarily show only thesecondary curves, their general direction being at right anglesto the axis of the pulp canal. Throughout their course theygive off an enormous number of very fine branches extendingfrom tubule to tubule. These are so numerous that insuitably prepared sections they may be said to look like theinterlacing twigs of a thicket or the rootlets of plants in thesoil. Fig. 137 gives a very good idea of the appearance. At the dentocemental junction the tubules end in irregular DENTINAL TUBULES IN THE ROOT PORTION 175 anastomosing spaces, which cause the appearance of thegranular layer of Tomes (Fig. 138). From a consideration of the preceding it will be seen thatit is usually not difficult to determine whether a field of Fig. 136. Dentine at dento-enamel junction, showing tubules cut longitudinally: Dt, dentinaltubules; D, dentine matrix. (About 760 X) dentine seen under the microscope was taken from the crownor the root of a tooth. The structural characteristics of thetwo regions may be summarized as follows: In the crown,the tubules show both the primary and the secondary curves. 176 THE DENTINE In the root, the tubules show only the secondary the crown, the lateral branches are few and inconspicuousand the tubules branch in a characteristic way at the dento-enamel junction. In the root, the lateral branches are very Fig. 137
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectteeth, bookyear1912
