tooth, pi. teeth

[A.S. toth.] One of the hard conical structures set in the alveoli of the upper and lower jaws, employed in mastication and a isting also in articulation. tooth is a dermal structure, not bone; it is composed of dentine (subs tanti a* ebumea [BNA]), encased in cement (subs tanti a* o ea [BNA]) on the covered portion, and enamel (subs tanti a* adamant in a [BNA]), on its -exposed portion. It consists of a root (radix) buried in the alveolus, a neck (collum) covered by the gum, and a crown (corona) the exposed portion. In the center is a hollow, the tooth-cavity or pulp-cavity (cavum dent is [BNA]), filled with a connective-ti ue reticulum containing a jelly-like substance (pulp a dent is) and blood-ve els and nerves which enter through a canal at the apex of the root. The 20 milk-teeth or deciduous teeth (see dens* deciduus) appear between the sixth or ninth and the twenty-fourth months of life. These fall out and are replaced by the 32 permanent teeth (see dens* permanens} appearing from the 5th or 7th to the i6th or 23d years. There are four kinds of teeth; incisor (densincisivus), canine (dens can in us), bicuspid or premolar (dens premolar is), and molar (dens molar is). See dens, denial, dentition, and teeth. axle t., molar t bicus'pid t., bicus'pidate t., dens premolar is. buck t., a tooth which has erupted outside of the dental arch, ca'nine t., dens can in us. cro -pin t., an artificial t. in which the pins are placed horizontally, cuspid t., cus'pidate t., dens can in us. decid'uous t., milk t. eye t., the canine tooth, on either side.