. Kirkes' handbook of physiology . LOWER CENTRALINCISORS. UPPERINCISORS. FIRST MOLAR AND LOWER LATERAL INCISORS. CANINES. SECOND MOLARS. 6 to 9 8 to 12 12 tO 15 18 to 24 24 to 30 THE TEETH 51 Permanent Teeth. Middle Line of Jaw. jfiars. SPoidaSrs°r Canine. Incisors. T • „ n ? „ Bicuspids or True Incisors. Canine. Prei£olars. Molars. The age at which each permantnt tooth is cut is indicated in this table in years: FIRST INCISORS. BICUSPIDS OR PRE-MOLARS. CANINES. SECONDMOLARS. THIRD MOLARS. Centrals. Laterals. First. Second. WISDOMS. 6 7 8 9 IO 12 tO 14 12 tO 15 17 to 25 Structure. A tooth is g
. Kirkes' handbook of physiology . LOWER CENTRALINCISORS. UPPERINCISORS. FIRST MOLAR AND LOWER LATERAL INCISORS. CANINES. SECOND MOLARS. 6 to 9 8 to 12 12 tO 15 18 to 24 24 to 30 THE TEETH 51 Permanent Teeth. Middle Line of Jaw. jfiars. SPoidaSrs°r Canine. Incisors. T • „ n ? „ Bicuspids or True Incisors. Canine. Prei£olars. Molars. The age at which each permantnt tooth is cut is indicated in this table in years: FIRST INCISORS. BICUSPIDS OR PRE-MOLARS. CANINES. SECONDMOLARS. THIRD MOLARS. Centrals. Laterals. First. Second. WISDOMS. 6 7 8 9 IO 12 tO 14 12 tO 15 17 to 25 Structure. A tooth is generally described as possessing a crown,neck, and root or roots. The crown is the portion which projects beyondthe level of the gum. The neck is that constricted portion just below the crownwhich is embraced by the free edges of the gum, and the root includes allbelow this. On making longitudinal and transverse sections through its center, figure61, A, B, a tooth is found to be principally composed of a hard superficial. Fig. 60.—Normal Well-formed Jaws, from which the Alveolar Plate has been in great partRemoved, so as to expose the Developing Permanent Teeth in their Crypts in the Jaws. (Tomes.) material, dentine or ivory, which is hollowed out into a central cavity whichresembles in general shape the outline of the tooth, and is called the pulp-cavity. The tooth pulp is composed of fibrous connective tissue, blood-vessels,nerves, and large numbers of cells of varying shapes, and on the surface in 52 CELL DIFFERENTIATION AND THE ELEMENTARY TISSUES close connection with the dentine a specialized layer of cells called odonto-blasts, which are elongated columnar cells with a large nucleus at the taper-ing ends farthest from the dentine. The cells are all embedded in a mucoidgelatinous matrix. The blood-vessels and nerves enter the pulp through a small openingat the apical extremity of each root. A layer of very hard calcareous matter, the enamel, caps the dentine ofth
Size: 1610px × 1553px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectphysiology, bookyear1
