Teeth (latin. Dentes; the toothed Dens; dentis = the tooth; dental = concerning the tooth; griech. Odous; Plural Odontes) are hard things in the oral cavity, which form the dentures as modified parts of the Hautskeletts in their whole. They developed from the simple skin teeth of premature fish. In the process of the evolution the shed teeth merged into hard things with basal bone mass, Dentinkrone and internal

With the teeth food is seized, cut up and to grind. They developed with the vertebrate animals and with humans after the form operational principle. With humans come as functions still the sound formation (in particular the S-sound) and social functions in addition, with animals function them also as weapons.

Genuine and false teeth

With respect to the animal realm one differentiates genuine and false teeth.

1. The genuine teeth consist of bloom Dentin and cement as well as a Pulpa. They are called also because the Dentin forms the main part (see heterodontes dentures).
2. With the false teeth the hard substances bloom, Dentin and cement are missing. It concerns usually horn teeth, as they are to be found e.g. in the throat and in the esophagus of the leather turtles. Primitive rootless teeth occur with fish, amphibians and reptiles and represent the Grundtyp of the teeth. They can have the form by easily course-sharpened, conical cone teeth, be reshuffled those with sharks sharp-edged or more-jaggedly, with fish to plaster teeth, with queues to poison teeth can (see homodontes dentures).

Kinds of tooth

With humans and most other mammals one differentiates (Incisivi), (Canini, catch teeth) and molars. The molars become into the and meal teeth (molecular) partitions.

The adult humans possesses 32 teeth with the wisdom teeth as a rule: in the upper and lower jaw on the right of and on the left of ever 2 meal teeth and 2 and wisdom tooth (together thus 20), ever one Eckzahn (together 4) and ever 2 (together 8). The milk dentures (temporary dentures of the children) possess however only 20 teeth; the teeth 6.7.8 both sides (thus the rear molars) are missing, because the Kiefer does not have yet the final size.

See also: Tooth formula

Numeric code of the teeth - the F.D.I pattern

For the avoidance of misunderstandings the teeth of humans in the dentistry are clearly designated by the dentures formula. The dentures are divided in addition into 4 quadrants, i.e. per Kiefer the division between the middle takes place. These quadrants serve the tooth designation as the first number:

• right above = 1 (with milk teeth: 5)
• left above = 2 (with milk teeth: 6)
• at the bottom left hand corner = 3 (with milk teeth: 7)
• down right = 4 (with milk teeth: 8)

The individual teeth are then durchnummeriert from the front in each case beginning. The left lower wisdom tooth carries thus the designation 38 (speak: three eight), during which first upper left Schneidezahn as 21 (speak: two one are designated).

The F.D.I. - Pattern of which since 1970 of the Dentaire international is recommended, is thus computerized and at present world-wide most frequently used.

In particular it is to be made certain that in the dental medicine - as also in the general medicine - which is described system in principle from the view of the patient. That is, while for example tooth 38, which links lower wisdom tooth, with the patient in the left mouth half lies, the left one of the opposite-sitting Behandler noticed as right.

Structure of the tooth

Each tooth consists of the tooth crown (Corona dentis), the tooth neck (Collum dentis) and the tooth root (Radix dentis) and is composed of several layers. What outward in the healthy dentures one sees by the tooth, is only the Zahnschmelz, which covers like a crown the Zahnbein (Dentin), lying inside. The Dentin again encloses that Zahnmark (Pulpa).

Zahnschmelz (Enamelum)

The Zahnschmelz is the hardest substance of the human body. It consists to 95 per cent of hydroxyl apatite (Ca5 (PO4) 3 (OH)), a crystalline material, whose principal part is calcium and phosphate. The Zahnschmelz is for water-soluble materials slightly permeable, for example for its components calcium and phosphate, as well as for fluorides. By fluorides that becomes hydroxyl apatite in harder fluorine apatite (Ca5 (PO4) 3 (F)) converted. Therefore these are used for the hardening of the Zahnschmelzes in Zahnpasten. However acids can harm the tooth, because they extract the calcium and phosphate from the Zahnschmelz and it thereby up-soft (see Karies).

Zahnbein (Dentin)

Under the Zahnschmelz is the Zahnbein or Dentin. It represents the bulk of the tooth. The hard substance of the Dentins exists as with the Zahnschmelz made of calcium and phosphate, however only to two thirds, the remainder is protein and water, why Dentin is softer and more susceptible to Karies than the Zahnschmelz. The Dentin is pain sensitive. Heat, cooling and contact attractions lead to liquid movements into the (within the range of the tooth neck to to the surface are enough can). This provokes the Tomes' fibers, cell extensions of the Odontoblasten (Dentin screen end cells). The Odontoblasten stands with free nerve ending in connection, which pass the attraction on as pain sensation to the central nervous system.

Zahnmark (Pulpa)

The Dentin encloses again the internal part of the tooth, Pulpa or Zahnmark mentioned, which pulled through from blood vessels and nerve fibers become.

Tooth cement (Cementum)

Within the root range the Dentin is covered by the tooth cement, the third tooth hard substance beside the Zahnschmelz and the Dentin. The tooth cement encloses the Wurzeldentin as thin layer, is the outside covering of the tooth and "immures "the tooth root in the Kiefer. But the connection to the Kieferknochen, in which each tooth is hung up in its tooth subject (alveole), has a certain elasticity (see tooth retaining apparatus).

Tooth characteristics

In order to determine an extracted tooth clearly, there are certain tooth characteristics:

• Angle characteristic: from vestibular view the angle between cut edge and the is pointed than the angle between the cut edge and the
• Curvature characteristic: regarded of okklusal, the mesiale portion of the vestibular surface is more strongly curved than the distal portion.
• Root characteristic: The root point bends mostly after distal, exceptions forms repeatedly the lower middle
• Crown escape: The crown of the lower jaw side teeth leans after lingual.

Root lots of teeth

With some mammals rootless teeth are trained. They possess no root channel and grow time life, contrary to the root teeth. Permanent growth is within limits held by the tooth abrasion. Regenerating teeth are also with fish, Amphibians and reptiles. Root lots of teeth with mammals are:

• all teeth of the hare-well-behaved (rabbit, hare.), the Chinchillas and the guinea pigs
• the Canini of the male pigs (here also called Hauer or rifles) as well as the with elephant, walrus and river horse
• the gnawing teeth of the different rodents.

Tooth change

With most mammals there is a unique tooth change (Diphyodontie). First milk teeth are put on (lacteale Dentition), which are replaced later by "second" or lasting teeth (permanent Dentition). The molecular ones (rear molars) have generally no milk tooth predecessors, it develop only in the lasting dentures.

With fish, amphibians and reptiles the teeth of time life can be replaced again and again by new (Polyphyodontie). Admit for this e.g. are Zebrafi and the "gun dentures" of the sharks.

Illnesses and important treatment forms

The most frequent illness of the teeth and humans at all is the Zahnkaries Also illnesses of the tooth retaining apparatus (see gums, Parodontitis and Parodontose) are frequent.

Already in the Steinzeit ignited teeth were expert pulled, and for thousands of years belong fillings (vulgo "Plomben"), isolated tooth crowns and Kiefer operations to the health care of culture peoples.

If today from necessary extractions become larger tooth spacings result, frequently an artificial denture ("third dentures") or a bridge is used. For approximately 20 years exists also the possibility of metallic tooth implants, which in-grow later in the Kiefer and are Increasing meaning has also the mouth hygiene, which is offered from dentists to the healthy attitude of the gums.

Cave: in rare cases acutely arising toothache can be only symptom of a cardiac infarct.

See also

• Dental medicine
• Dentures - milk dentures - Parodontologie - dentist
• Dental care - tooth clarification - tooth lead - tooth clip

Related links

• www.zahnwissen.de
• Inclined teeth are a consequence of cooking
• www.wissenschaft.de: Researchers can determine on the basis fossil teeth, how Vormen nourished themselves

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