tooth
(tooth 
)
(tēth )
Plural: teeth
Any of the hard, bony structures of the upper and lower jaws used for cutting, tearing, and chewing. A tooth consists of a crown portion above the gum, a root portion embedded in a socket (alveolus) of the jaw bone, and a neck or cervical constricted region between the crown and root. The soft-tissue gingiva covers the neck and root to a variable extent, depending on age and oral hygiene. The major portion of a tooth consists of dentin, which is harder than bone; enamel; and cementum, which is similar to bone. The pulp cavity contains the dental pulp. Each tooth has five surfaces: occlusal, mesial, distal, lingual, and facial or buccal.
Every human has two complete sets of teeth during his or her life. The 20 primary teeth are the first set of teeth to develop. They exfoliate by age 14 and are replaced by the 32 permanent teeth. The permanent teeth include the incisors, canines (cuspids), premolars (bicuspids), and molars. On average, a child should have 6 teeth at 1 year, 12 teeth at 18 months, 16 teeth at 2 years, and 20 teeth at 12 years. Some children are born with a few erupted teeth; in other children the teeth may not appear until 16 months.
Patient Care: Health care professionals should assess patients’ teeth and gums during physical examinations, educate patients about routine dental hygiene (brushing, flossing, gum stimulation, use of oral rinses), and refer them to a dental professional for dental caries, eruption anomalies, or periodontal problems.
SEE: dental plaque ; periodontal disease.
accessional t.A permanent molar tooth that arises without deciduous predecessors in the dental arch.
anterior t.Any of the central and lateral incisors and /or the canines, located adjacent to the midline of the maxilla or mand ible.
SEE: posterior tooth .
bicuspid t.A permanent premolar tooth. There are eight premolars, two in each quadrant (four in each jaw) between the canines and molars. Premolars have two or three cusps on the occlusal surface.
SEE: premolar.
SEE: canine (2).
cracked t.A tooth whose enamel and dentin are fractured.
dead t.A tooth from which the pulp has been removed by endodontic treatment and is therefore considered nonvital according to clinical stand ards. The term is imprecise because, if the periodontal tissues are healthy, the tooth will continue to function without symptoms.
deciduous t.Any of the 20 teeth that make up the primary dentition, which are shed and replaced by the permanent teeth. SYN: baby tooth; milk tooth; primary tooth.
SEE: primary dentition ; illus..
hypersensitive t.A tooth sensitive to temperature changes, sweets, or percussion. It may exhibit gingival recession, exposed root dentin, caries, or periodontal disease.
Common treatments for hypersensitivity include topical varnishes, sealants, and topical fluoride applications. Other treatments include application of silver nitrate, formalin, glycerin, strontium chloride, potassium nitrate, calcium compounds, sodium citrate, and potassium oxalate.
The patient can reduce sensitivity by a regimen of plaque control, dentifrice with fluoride, self-applied fluoride, and control of diet.
impacted t.A tooth unable to erupt due to crowding by adjacent teeth, malposition of the tooth, or developmental disturbances.
SEE: incisor.
SEE: 2molar.
peg t.An abnormally shaped tooth of genetic origin. It is usually noted as a maxillary lateral incisor with a smaller conical crown.
permanent t.Any of the 32 teeth that develop as the second dentition and replace the deciduous teeth. SYN: secondary tooth.
SEE: permanent dentition ; succedaneous tooth ; deciduous tooth for illus.
posterior t.Any of the bicuspid and molar teeth.
SEE: anterior tooth .
SEE: premolar.
stained t.Deep or superficial discoloration of a tooth. Several conditions may cause this, e.g., exposure of the fetus to tetracycline that the mother took during pregnancy or exposure to high levels of fluoride in drinking water. The stains may be covered by bonding.
SEE: bonding (1).
submerged t.A tooth that is below the plane of occlusion. Usually it is a deciduous tooth retained as a result of ankylosis.
succedaneous t.In dentistry, a permanent tooth that replaces a normally erupted deciduous tooth. It includes the premanent incisors, cuspids, and premolars. The deciduous molars are replaced by the permanent premolars, which are not succedaneous teeth.
SEE: permanent tooth .
supernumerary t.An extra tooth that exceeds the usual number of teeth. Extra teeth develop in approx. 2% of the population, with almost all of them being maxillary incisors or mesiodens. A cleft palate or other developmental disturbances disrupt the dental lamina and often result in palatal supernumerary teeth.
tricuspid t.A tooth with a crown that has three cusps.
wisdom t.Any of the third most-distal molars on each side of both jaws. These four molars may appear as late as the 25th year or may never erupt.