A report on Tooth and Hydroxyapatite

A chimpanzee displaying its teeth
Hydroxyapatite crystals on matrix
Section through the ivory tusk of a mammoth
Buccal view of top incisor from Rattus rattus. Top incisor outlined in yellow. Molars circled in blue.
Needle-like hydroxyapatite crystals on stainless steel. Scanning electron microscope picture from University of Tartu.
Buccal view of the lower incisor from the right dentary of a Rattus rattus
Nanoscale coating of Ca-HAp, image taken with scanning probe microscope
Lingual view of the lower incisor from the right dentary of a Rattus rattus
A 3D visualization of half of a hydroxyapatite unit cell, from x-ray crystallography
Midsagittal view of top incisor from Rattus rattus. Top incisor outlined in yellow. Molars circled in blue.
Lingual view of top incisor from Rattus rattus. Top incisor outlined in yellow. Molars circled in blue.
Teeth of great white shark
The European medicinal leech has three jaws with numerous sharp teeth which function like little saws for incising a host.
The limpet rasps algae from rocks using teeth with the strongest known tensile strength of any biological material

Hydroxyapatite is present in bone and teeth; bone is made primarily of HA crystals interspersed in a collagen matrix—65 to 70% of the mass of bone is HA.

- Hydroxyapatite

Dentine can be as hard as the rest of teeth and is composed of collagen fibres, reinforced with hydroxyapatite.

- Tooth
A chimpanzee displaying its teeth

3 related topics with Alpha


Labeled molar

Tooth enamel

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Labeled molar
Parts of a tooth, including the enamel (cross section).
Histologic slide showing a developing tooth. The mouth would be in the area of space at the top of the picture.
Histologic slide showing enamel formation
The effects of bruxism on an anterior tooth, revealing the dentin and pulp which are normally hidden by enamel
Common dentistry trays filled with fluoride foam
An X-ray showing enamel and dentin replaced by an amalgam restoration
Irreversible enamel defects caused by an untreated celiac disease. They may be the only clue to its diagnosis, even in absence of gastrointestinal symptoms, but are often confused with fluorosis, tetracycline discoloration, or other causes. The National Institutes of Health include a dental exam in the diagnostic protocol of celiac disease.
Teeth of a rottweiler

Tooth enamel is one of the four major tissues that make up the tooth in humans and many other animals, including some species of fish.

The primary mineral is hydroxyapatite, which is a crystalline calcium phosphate.

Parts of a tooth, including dentin


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Parts of a tooth, including dentin
Dentinal sclerosis

Dentin (American English) or dentine ( or ) (British English) (substantia eburnea) is a calcified tissue of the body and, along with enamel, cementum, and pulp, is one of the four major components of teeth.

By volume, 45% of dentin consists of the mineral hydroxyapatite, 33% is organic material, and 22% is water.

Destruction of a tooth by dental caries and disease.

Tooth decay

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Destruction of a tooth by dental caries and disease.
(A) A small spot of decay visible on the surface of a tooth. (B) The radiograph reveals an extensive region of demineralization within the dentin (arrows). (C) A hole is discovered on the side of the tooth at the beginning of decay removal. (D) All decay removed; ready for a filling.
Diagrammatic representation of acidogenic theory of causation of dental caries. Four factors, namely, a suitable carbohydrate substrate (1), micro-organisms in dental plaque (2), a susceptible tooth surface (3) and time (4); must be present together for dental caries to occur (5). Saliva (6) and fluoride (7) are modifying factors.
A Gram stain image of Streptococcus mutans.
"Stephan curve", showing sudden decrease in plaque pH following glucose rinse, which returns to normal after 30–60 min. Net demineralization of dental hard tissues occurs below the critical pH (5.5), shown in yellow.
Tooth decay
Microbe communities attach to tooth surface and create a biofilm. As the biofilm grows an anaerobic environment forms from the oxygen being used up. Microbes use sucrose and other dietary sugars as a food source. The dietary sugars go through anaerobic fermentation pathways producing lactate. The lactate is excreted from the cell onto the tooth enamel then ionizes. The lactate ions demineralize the hydroxyapatite crystals causing the tooth to be degraded.
The progression of pit and fissure caries resembles two triangles with their bases meeting along the junction of enamel and dentin.
The faster spread of caries through dentin creates this triangular appearance in smooth surface caries.
The tip of a dental explorer, which is used for caries diagnosis
A dental infection resulting in an abscess and inflammation of the maxillary sinus
Tooth samples imaged with a non-coherent continuous light source (row 1), LSI (row 2) and pseudo-color visualization of LSI (row 3).
G. V. Black Classification of Restorations
Rampant caries caused by methamphetamine abuse.
Toothbrushes are commonly used to clean teeth.
Annual caries incidence increases exponentially with annual per capita sugar consumption. Data based on 10,553 Japanese children whose individual lower first molar teeth were monitored yearly from the age of 6 to 11 years of age. Caries plotted on a logarithmic scale, so line is straight.
Common dentistry trays used to deliver fluoride.
Fluoride is sold in tablets for cavity prevention.
An amalgam used as a restorative material in a tooth.
A tooth with extensive caries eventually requiring extraction.
An image from Omne Bonum (14th century) depicting a dentist extracting a tooth with forceps.

Tooth decay, also known as cavities or caries, is the breakdown of teeth due to acids produced by bacteria.

These minerals, especially hydroxyapatite, will become soluble when exposed to acidic environments.