What does it mean when you dream about teeth?
Something that one can “get one’s teeth into” relates to a power or control issue. Losing the teeth may reflect a loss of power as well as a loss of one’s grasp of life circumstances. Biting or being bitten suggests struggling for control in an aggressive manner. (See also Bite, Dentures).
Teeth
(dreams)Teeth
the bonelike structures found in the mouth in man and most gnathostomatous vertebrates (in some fish, also in the pharynx) that are used for grasping and holding food and for its mechanical processing, or mastication. Three anatomical parts of teeth may be distinguished: the crown, neck, and root, or roots. The main bulk of the tooth is composed of dentin, covered by enamel on the crown area and, in mammals, by cementum on the neck and root. Inside the tooth is a cavity, the root canal, which is filled with pulp. The canal opens at the end of the root, forming the apical foramen, through which blood vessels and nerve fibers enter the tooth cavity.
In the process of animal evolution teeth originally derived from the dermal teeth, or placoid scales, offish. Teeth appear during embryonic development as epithelial folds— the “dental lamina” with the rudiments of certain teeth. Mesenchymal cells of the dermis form a thickening (dental papillae) under each rudiment, over which epithelial cells of the dental lamina are suspended in the form of a cap, the so-called enamel organ. The internal layer of cells of the dental lamina participates in the formation of enamel; the external cells of the dental papilla, or odontoblasts, form dentin, and the mesenchymal cells surrounding it form cementum. The developing teeth emerge by cutting through the mucous membrane of the gum.
In most vertebrates teeth are replaced by new ones as they wear out. Teeth may be replaced continuously throughout life (polyphyodont dentition; most vertebrates, excluding mammals), only once at a young age (diphyodont dentition; the majority of mammals), or not at all (monophyodont dentition; certain mammals such as the edentates and cetaceans). In most fish and reptiles and in amphibians all the teeth are identical (isodont, or homodont, dentition); some fish and reptiles and, as a rule, mammals have teeth of various forms (heterodont dentition). In cyclostomes special horny teeth develop, which are not homologous to the teeth of gnathostomatous vertebrates. In fish the teeth occur in the soft tissues and on the bones of the mouth and on the branchial arches (pharyngeal teeth). Some fish, for example, loach and carp, have only pharyngeal teeth, while others, such as adult sturgeon, have no teeth at all. In amphibians the teeth occur on the bones of the mouth. In reptiles the teeth are usually ankylosed to the jaws (to their rim or to the inside) and are seldom found on the other bones of the mouth. In crocodiles the teeth are set in sockets (alveoli) in the jaws. In venomous snakes, poison teeth develop in the upper jaw that have a canal connecting with the poison gland. Turtles have no teeth; their function is performed by the cutting edges of the horny jaw cases. The modern birds have no teeth, although fossil birds, such as the archaeopteryx and ichthyornis, had teeth in the alveoli of the jaws. In mammals the teeth are implanted in the alveoli of the jaws. There are no teeth in the adults of some edentates, in monotremes, and in whalebone whales.
The front teeth, or incisors, are scalpriform and are used for grasping and cutting food; there may be from one to five pairs in each half of the upper and lower jaws. Next to the incisors are the conelike canines (one pair), which have the function of grasping and tearing food (in predators) and are weapons of defense (in artiodactyl and perissodactyl omnivores and in some pinnipeds and cetaceans). The back teeth, or molars (up to eight pairs), are complex in shape and are used to grind food; molars are divided into premolars (three-four pairs), and true molars (three-four pairs), which have two or more roots. The shape and number of teeth in various species of mammals are more or less constant and are an important taxonomic characteristic. The composition and number of teeth in mammals are conventionally expressed by a dental formula, in which the number of teeth in one-half of the upper (numerator) and lower (denominator) jaw are indicated. Thus the dental formula of a dog is:
where i is incisors (incisivi), c canines (canini), pm premolars (praemolares), m molars (molares), and the total number of teeth 44. The initial letters of the Latin names are usually omitted:
In predators the number of teeth does not exceed 44; in artiodactyls and perissodactyls and in rodents the number of teeth varies greatly; some edentates have 18–20 teeth and some marsupials as many as 58; dentate cetaceans of the dolphin family may have up to 250 teeth. Different teeth develop unequally, for example, tusks, depending on their function. In predators the canines are well developed and in rodents, the incisors and molars; in rodents the canines are lost and in their place is a toothless space, the diastema. In some mammals the teeth are continuously growing, for example, the incisors of rodents. In lemurs and monkeys the number of teeth is reduced to 32 (Old World monkeys), which coincides with the number of teeth in man.
B. S. MATVEEV
In man, besides grinding, biting, and holding food, teeth play a major role in the pronunciation of certain sounds and affect facial appearance (especially the front teeth). The teeth are arranged in the jaws in the form of an arch. The teeth of the upper and lower jaws interlock according to their anatomical structures, creating the bite, or occlusion. The formula of the milk (deciduous) teeth is:
The formula of the permanent teeth is:
In these formulas the numbers above the horizontal line indicate the upper teeth, those below the line the lower teeth; the numbers to the left of the vertical line represent the right side of a dentition, those to the right of the vertical line the left side. Individual teeth are designated accordingly, for example: 
is the deciduous third upper left tooth and 
is the permanent third lower right.
Depending on their shape and function, teeth are divided into incisors, with flat crowns and cutting edges (for biting off food); canines, with a conelike crown (for tearing food); premolars (with a cuboid crown and two cusps on the chewing surface); and molars (with four-five cusps on the chewing surface), used for grinding food. The incisors, canines, and premolars (except the first and second upper) have one root, the first and second upper premolars and the lower molars have two roots, and the upper molars have three roots. An individual’s teeth are unique, corresponding to the shape of the face; this is of great significance for prosthodontics and for forensic medicine.
The tooth root is connected to the alveolus of the jaw by fibers of the root covering (pericementum, periodontal membrane), which are attached to the cementum at one end and to the wall of the alveolus at the other. The neck of the tooth is firmly implanted in the gum, the edge of which loosely adjoins the tooth, forming a crevice-like space (the pocket) that extends around the periphery of the tooth to a depth of 1–2 mm.
Each jaw has ten milk teeth, consisting of four incisors, two canines, and four molars and 16 permanent teeth, including four incisors, two canines, four premolars, and six molars.
The formation of teeth in the fetus begins in the fifth week of the embryonic period. When the infant is born, all 20 milk teeth are lying in the alveoli of the jaws. Some permanent teeth—the first molars, incisors, and canines—are also formed intrauterinely. The rest of the permanent teeth begin to form after birth. Eruption of teeth occurs twice in a human life: the milk teeth in the infant erupt between the ages of six months and 24–30 months and the permanent teeth between 5–6 and 14 years (the third molars or wisdom teeth between 17 and 25 years).
Diseases of the teeth may develop through the influence of unfavorable factors on the teeth or as a result of diseases of internal organs and systems of the body, or they may be congenital. Diseased teeth may become a focus of infection and may lead to serious disturbances in the activity of the gastrointestinal tract, the cardiovascular system, the kidneys, and joints. The most common affections of teeth are tartar, dental caries, pulpitis, and periodontitis.
A. I. RYBAKOV
The form and structure of human teeth are also studied by anthropologists. Teeth are preserved better than other bony fossil remains of ancient people, so that the study of teeth has played a large role in solving problems of the origin of man. In the process of man’s evolution his teeth have undergone reduction, resulting in smaller teeth and more simplified crowns. The canines and incisors were already smaller in prehominids and early hominids. The premolars and molars changed during the entire process of anthropogenesis under the influence of various factors—changes in diet, general changes in the dimensions and form of the facial cranium, and genetic factors.
The tooth structure of modern man shows considerable variation. Long periods of past isolation in different regions of the world has caused certain small morphological details to appear frequently in some groups and rarely in others. These differences are studied in ethnic anthropology and are used, along with other anthropological data, to solve problems of the origin of races and peoples.
REFERENCE
Zubov, A. A. Odontologiia. Moscow, 1968.A. A. ZUBOV