A report on Hydroxyapatite and Dental fluorosis

Hydroxyapatite crystals on matrix
Mild fluorosis: in its usual mildest form, fluorosis appears as opaque white patches on the enamel
Hydroxyapatite
Amelogenesis imperfecta: this condition can be mistaken for fluorosis
Needle-like hydroxyapatite crystals on stainless steel. Scanning electron microscope picture from University of Tartu.
Enamel hypoplasia caused by untreated celiac disease: this condition is often confused with fluorosis
Nanoscale coating of Ca-HAp, image taken with scanning probe microscope
Severe fluorosis: brown discolored and mottled enamel of an individual from a region with high levels of naturally occurring fluoride
A 3D visualization of half of a hydroxyapatite unit cell, from x-ray crystallography
Severe fluorosis: the enamel is pitted and discolored

Naturally occurring apatites can, however, also have brown, yellow, or green colorations, comparable to the discolorations of dental fluorosis.

- Hydroxyapatite

Hydroxyapatite is converted to fluoroapatite in a three step process.

- Dental fluorosis
Hydroxyapatite crystals on matrix

4 related topics with Alpha

Overall

Labeled molar

Tooth enamel

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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.

Some groups have spoken out against fluoridated drinking water, for reasons such as the neurotoxicity of fluoride or the damage fluoride can do as fluorosis.

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

Water fluoridation

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Controlled adjustment of fluoride to a public water supply solely to reduce tooth decay.

Controlled adjustment of fluoride to a public water supply solely to reduce tooth decay.

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

Although fluoridation can cause dental fluorosis, which can alter the appearance of developing teeth or enamel fluorosis, the differences are mild and usually not an aesthetic or public health concern.

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.

Destruction of a tooth by dental caries and disease.

Tooth decay

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Breakdown of teeth due to acids produced by bacteria.

Breakdown of teeth due to acids produced by bacteria.

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.

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

The differential diagnosis for dental caries includes dental fluorosis and developmental defects of the tooth including hypomineralization of the tooth and hypoplasia of the tooth.

Defluoridation

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Downward adjustment of the level of fluoride in drinking water.

Downward adjustment of the level of fluoride in drinking water.

An excess of fluoride in drinking water causes dental fluorosis and skeletal fluorosis.

Calcium amended-hydroxyapatite is the most recent defluoridation technique in which aqueous calcium is amended to the fluoride contaminated water prior to contact with uncalcined synthetic hydroxyapatite adsorbent.