A report on Tooth decay and Hydroxyapatite

Destruction of a tooth by dental caries and disease.
Hydroxyapatite crystals on matrix
(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.
Hydroxyapatite
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.
Needle-like hydroxyapatite crystals on stainless steel. Scanning electron microscope picture from University of Tartu.
A Gram stain image of Streptococcus mutans.
Nanoscale coating of Ca-HAp, image taken with scanning probe microscope
"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.
A 3D visualization of half of a hydroxyapatite unit cell, from x-ray crystallography
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 enamel can become demineralised due to various factors, including acidic erosion and dental caries.

- Hydroxyapatite

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

- Tooth decay
Destruction of a tooth by dental caries and disease.

7 related topics with Alpha

Overall
Labeled molar

Tooth enamel

6 links

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

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

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

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

The high mineral content of enamel, which makes this tissue the hardest in the human body, also makes it demineralize in a process that often occurs as dental caries, otherwise known as cavities.

Fluoridation does not affect the appearance, taste or smell of drinking water.

Water fluoridation

3 links

Fluoridation does not affect the appearance, taste or smell of drinking water.
A cavity starts in a tooth's outer enamel and spreads to the dentin and pulp inside.
Fluoride monitor (at left) in a community water tower pumphouse, Minnesota, 1987
Geographical areas associated with groundwater having over 1.5 mg/L of naturally occurring fluoride, which is above recommended levels.
Detail of southern Arizona. Areas in darker blues have groundwater with over 2 mg/L of naturally occurring fluoride.
A mild case of dental fluorosis, visible as white streaks on the subject's upper right central incisor.
Demineralization and remineralization of dental enamel in the presence of acid and fluoride in saliva and plaque fluid.
Fluoride toothpaste is effective against cavities. It is widely used, but less so among the poor.
Fluoridated iodized salt sold in Germany
1909 photograph by Frederick McKay of G.V. Black (left), Isaac Burton and F.Y. Wilson, studying the Colorado brown stain.
H. Trendley Dean set out in 1931 to study fluoride's harm, but by 1950 had demonstrated the cavity-prevention effects of small amounts.
Percentage of population receiving fluoridated water, including both artificial and natural fluoridation, as of 2012. 80–100% 60–80% 40–60% 20–40% 1–20% < 1% unknown

Water fluoridation is the controlled adjustment of fluoride to a public water supply solely to reduce tooth decay.

When enough acid is produced to lower the pH below 5.5, the acid dissolves carbonated hydroxyapatite, the main component of tooth enamel, in a process known as demineralization.

Parts of a tooth, including dentin

Dentin

2 links

Calcified tissue of the body and, along with enamel, cementum, and pulp, is one of the four major components of teeth.

Calcified tissue of the body and, along with enamel, cementum, and pulp, is one of the four major components of teeth.

Parts of a tooth, including dentin
Dentinal sclerosis

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

Events such as tooth decay and tooth wear can also initiate dentine formation.

Remineralisation of teeth

2 links

Demineralised by acid in plaque and becomes partly dissolved crystal. This in turn is remineralised by fluoride in plaque to become a fluorapatite-like coating on remineralised crystal.|Example: Demineralization and remineralization of dental enamel in the presence of acid and fluoride in saliva and plaque fluid.

Demineralised by acid in plaque and becomes partly dissolved crystal. This in turn is remineralised by fluoride in plaque to become a fluorapatite-like coating on remineralised crystal.|Example: Demineralization and remineralization of dental enamel in the presence of acid and fluoride in saliva and plaque fluid.

Tooth remineralization is the natural repair process for non-cavitated tooth lesions, in which calcium, phosphate and sometimes fluoride ions are deposited into crystal voids in demineralised enamel.

When enough acid is produced so that the pH goes below 5.5, the acid dissolves carbonated hydroxyapatite, the main component of tooth enamel.

Mild fluorosis: in its usual mildest form, fluorosis appears as opaque white patches on the enamel

Dental fluorosis

2 links

Common disorder, characterized by hypomineralization of tooth enamel caused by ingestion of excessive fluoride during enamel formation.

Common disorder, characterized by hypomineralization of tooth enamel caused by ingestion of excessive fluoride during enamel formation.

Mild fluorosis: in its usual mildest form, fluorosis appears as opaque white patches on the enamel
Amelogenesis imperfecta: this condition can be mistaken for fluorosis
Enamel hypoplasia caused by untreated celiac disease: this condition is often confused with fluorosis
Severe fluorosis: brown discolored and mottled enamel of an individual from a region with high levels of naturally occurring fluoride
Severe fluorosis: the enamel is pitted and discolored

People with fluorosis are relatively resistant to dental caries (tooth decay caused by bacteria), although there may be cosmetic concern.

Hydroxyapatite is converted to fluoroapatite in a three step process.

Toothpaste from a tube being applied to a toothbrush

Toothpaste

1 links

Paste or gel dentifrice used with a toothbrush to clean and maintain the aesthetics and health of teeth.

Paste or gel dentifrice used with a toothbrush to clean and maintain the aesthetics and health of teeth.

Toothpaste from a tube being applied to a toothbrush
Toothpaste is sold in many brands.
Icelandic postage stamp encouraging use of fluoridated toothpaste
A brand of red, blue and white striped toothpaste
The red area represents the material used for stripes, and the rest is the main toothpaste material. The two materials are not in separate compartments; they are sufficiently viscous that they will not mix. Applying pressure to the tube causes the main material to issue out through the pipe. Simultaneously, some of the pressure is forwarded to the stripe-material, which is thereby pressed onto the main material through holes in the pipe.
Promotional poster for the Kolynos toothpaste from the 1940s
Modern toothpaste gel, in a tube

Toothpaste is used to promote oral hygiene: it is an abrasive that aids in removing dental plaque and food from the teeth, assists in suppressing halitosis, and delivers active ingredients (most commonly fluoride) to help prevent tooth decay (dental caries) and gum disease (gingivitis).

Representative abrasives include particles of aluminum hydroxide (Al(OH)3), calcium carbonate (CaCO3), magnesium carbonate(MgCo3), sodium bicarbonate, various calcium hydrogen phosphates, various silicas and zeolites, and hydroxyapatite (Ca5(PO4)3OH).

A chimpanzee displaying its teeth

Tooth

2 links

Hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food.

Hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food.

A chimpanzee displaying its teeth
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.
Buccal view of the lower incisor from the right dentary of a Rattus rattus
Lingual view of the lower incisor from the right dentary of a Rattus rattus
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

In dogs, the teeth are less likely than humans to form dental cavities because of the very high pH of dog saliva, which prevents enamel from demineralizing.

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