. Cunningham's Text-book of anatomy. Anatomy. THE TEETH. 1113 Permanent canine 1st permanent premolar 2nd permanent premolar 1st permanent molar riN 2nd permanent molar DENTES. Each tooth is a calcified papilla of the raucous membrane of the mouth, and consists like that membrane of two chief portions—namely, the substantia eburnea or ivory ( dentine) derived from the connective tissue, and the substantia adaman- tina or adamant ( enamel) from the epithelial layer of the mucous membrane. The substantia eburnea constitutes the chief mass of the tooth, whilst the sub- stantia adamantina
. Cunningham's Text-book of anatomy. Anatomy. THE TEETH. 1113 Permanent canine 1st permanent premolar 2nd permanent premolar 1st permanent molar riN 2nd permanent molar DENTES. Each tooth is a calcified papilla of the raucous membrane of the mouth, and consists like that membrane of two chief portions—namely, the substantia eburnea or ivory ( dentine) derived from the connective tissue, and the substantia adaman- tina or adamant ( enamel) from the epithelial layer of the mucous membrane. The substantia eburnea constitutes the chief mass of the tooth, whilst the sub- stantia adamantina forms a cap for the portion which projects above the gum. There is also found in the teeth another special tissue—the substantia ossea ( cement), a form of modified bone—encasing the roots, which are formed chiefly of substantia eburnea. Both ivory and adamant, but parti- cularly the latter, are the hardest and most resistant struc- tures in the body, and are thus specially fitted for the func- tions which they have to perform. Dentes Decidui and Dentes Per- manentes (Decidu- ous and permanent teeth).—The mouth of the infant at birth contains no teeth, although a number, partly de- veloped, lie em- bedded in the jaws beneath the gum. Some six months later, teeth begin to appear, and by the end of the second year a set, known as the deciduous teeth ( milk teeth), twenty in number, has been "; Then follows a pause of about four years, during which no visible change takes place in the mouth, although in reality an active preparation for further develop- ment is going on beneath the gum. At the end of this period, namely, about the sixth year, the next stage in the production of the adult condition begins. It consists in the eruption of four new teeth—the first permanent molars—one on each side, above and below, behind those of the deciduous set. This is followed by the gradual falling out of the twenty teeth which have occupied the mouth since the
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1914
