Human tooth

Page semi-protected
Source: Wikipedia, the free encyclopedia.
This article is about the structure found in humans. For the teeth of other animals, see Tooth. For other uses, see Tooth (disambiguation).

Human tooth
canine teeth, situated in gums above and below.
Diagram of a human molar showing its major constituents
Details
Identifiers
Latindens
TA2914
Anatomical terminology]

Human teeth function to

mandible (lower jaw) and are covered by gums
. Teeth are made of multiple tissues of varying density and hardness.

Humans, like most other

mammals, are diphyodont, meaning that they develop two sets of teeth. The first set, deciduous teeth, also called "primary teeth", "baby teeth", or "milk teeth", normally eventually contains 20 teeth. Primary teeth typically start to appear ("erupt") around six months of age and this may be distracting and/or painful for the infant. However, some babies are born with one or more visible teeth, known as neonatal teeth
or "natal teeth".

Structure

Main article: Dental anatomy
There are four main types of teeth in humans, shown labelled here.

taxonomic
science as it is concerned with the naming of teeth and their structures. This information serves a practical purpose for dentists, enabling them to easily identify and describe teeth and structures during treatment.

The anatomic

supernumerary roots
.

Humans usually have 20 primary (deciduous, "baby" or "milk") teeth and 32 permanent (adult) teeth. Teeth are classified as incisors, canines, premolars (also called bicuspids), and molars. Incisors are primarily used for cutting, canines are for tearing, and molars serve for grinding.

Most teeth have identifiable features that distinguish them from others. There are several different notation systems to refer to a specific tooth. The three most common systems are the FDI World Dental Federation notation (ISO 3950), the Universal Numbering System, and the Palmer notation. The FDI system is used worldwide, the Universal only in the United States, while the older Palmer notation still has some adherents only in the United Kingdom.

Primary teeth

Among deciduous (primary) teeth, ten are found in the maxilla (upper jaw) and ten in the mandible (lower jaw), for a total of 20. The dental formula for primary teeth in humans is 2.1.0.22.1.0.2.

In the primary set of teeth, in addition to the canines there are two types of incisors—centrals and laterals—and two types of molars—first and second. All primary teeth are normally later replaced with their permanent counterparts.

The Universal Numbering System for adult human teeth. The view is from a dental practitioner's perspective, meaning tooth 1 is the upper right rear (third) molar.

Permanent teeth

Among permanent teeth, 16 are found in the maxilla and 16 in the mandible, for a total of 32. The dental formula is 2.1.2.32.1.2.3. Permanent human teeth are numbered in a boustrophedonic sequence.

The maxillary teeth are the

wisdom teeth" and usually emerge at ages 17 to 25.[6] These molars may never erupt into the mouth or form at all.[citation needed] When they do form, they often must be removed. If any additional teeth form—for example, fourth and fifth molars, which are rare—they are referred to as supernumerary teeth (hyperdontia). Development of fewer than the usual number of teeth is called hypodontia
.

There are small differences between the teeth of males and females, with male teeth along with the male jaw tending to be larger on average than female teeth and jaw. There are also differences in the internal dental tissue proportions, with male teeth consisting of proportionately more dentine while female teeth have proportionately more enamel.[7]

Parts

Enamel

Main article: Tooth enamel

Enamel is the hardest and most highly

cusp, up to 2.5mm, and thinnest at its border, which is seen clinically as the CEJ.[10] The wear rate of enamel, called attrition, is 8 micrometers a year from normal factors.[11]

Enamel's primary mineral is hydroxyapatite, which is a crystalline calcium phosphate.[12] The large amount of minerals in enamel accounts not only for its strength but also for its brittleness.[10] Dentin, which is less mineralized and less brittle, compensates for enamel and is necessary as a support.[12] Unlike dentin and bone, enamel does not contain collagen. Proteins of note in the development of enamel are ameloblastins, amelogenins, enamelins and tuftelins. It is believed that they aid in the development of enamel by serving as framework support, among other functions.[13] In rare circumstances enamel can fail to form, leaving the underlying dentine exposed on the surface.[14]

Dentin

Main article: Dentin

Dentin is the substance between enamel or cementum and the pulp chamber. It is secreted by the odontoblasts of the dental pulp.[15] The formation of dentin is known as dentinogenesis. The porous, yellow-hued material is made up of 70% inorganic materials, 20% organic materials, and 10% water by weight.[16] Because it is softer than enamel, it decays more rapidly and is subject to severe cavities if not properly treated, but dentin still acts as a protective layer and supports the crown of the tooth.

Dentin is a mineralized connective tissue with an organic matrix of collagenous proteins. Dentin has microscopic channels, called dentinal tubules, which radiate outward through the dentin from the pulp cavity to the exterior cementum or enamel border.[17] The diameter of these tubules range from 2.5 μm near the pulp, to 1.2 μm in the midportion, and 900 nm near the dentino-enamel junction.[18] Although they may have tiny side-branches, the tubules do not intersect with each other. Their length is dictated by the radius of the tooth. The three dimensional configuration of the dentinal tubules is genetically determined.

There are three types of dentin, primary, secondary and tertiary.[19] Secondary dentin is a layer of dentin produced after root formation and continues to form with age. Tertiary dentin is created in response to stimulus, such as cavities and tooth wear.[20]

Cementum

Main article: Cementum

Cementum is a specialized bone like substance covering the root of a tooth.

periodontal ligaments can attach to the tooth for stability. At the cement to enamel junction, the cementum is acellular due to its lack of cellular components, and this acellular type covers at least ⅔ of the root.[21] The more permeable form of cementum, cellular cementum, covers about ⅓ of the root apex.[22]

Dental pulp

Main article: Pulp (tooth)

The dental pulp is the central part of the tooth filled with soft connective tissue.

T lymphocytes.[24]
The pulp is commonly called "the nerve" of the tooth.

Development

Main article: Human tooth development
Radiograph of lower right third, second, and first molars in different stages of development

Tooth development is the complex process by which teeth form from

the development of the embryo between the sixth and eighth weeks, and permanent teeth begin to form in the twentieth week.[25]
If teeth do not start to develop at or near these times, they will not develop at all.

A significant amount of research has focused on determining the processes that initiate tooth development. It is widely accepted that there is a factor within the tissues of the first pharyngeal arch that is necessary for the development of teeth.[26]

Tooth development is commonly divided into the following stages: the bud stage, the cap, the bell, and finally maturation. The staging of tooth development is an attempt to categorize changes that take place along a continuum; frequently it is difficult to decide what stage should be assigned to a particular developing tooth.[26] This determination is further complicated by the varying appearance of different histologic sections of the same developing tooth, which can appear to be different stages.

The

periodontal ligaments which connect teeth to the alveolar bone through cementum.[29]

Eruption

Main article: Tooth eruption
Bottom teeth of a seven-year-old, showing primary teeth (left), a lost primary tooth (middle), and a permanent tooth (right)

Tooth eruption in humans is a process in tooth development in which the teeth enter the mouth and become visible. Current research indicates that the periodontal ligaments play an important role in tooth eruption. Primary teeth erupt into the mouth from around six months until two years of age. These teeth are the only ones in the mouth until a person is about six years old. At that time, the first permanent tooth erupts. This stage, during which a person has a combination of primary and permanent teeth, is known as the mixed stage. The mixed stage lasts until the last primary tooth is lost and the remaining permanent teeth erupt into the mouth.

There have been many theories about the cause of tooth eruption. One theory proposes that the developing root of a tooth pushes it into the mouth. Another, known as the cushioned hammock theory, resulted from microscopic study of teeth, which was thought to show a

artifact
created in the process of preparing the slide. Currently, the most widely held belief is that the periodontal ligaments provide the main impetus for the process.

The onset of primary tooth loss has been found to correlate strongly with somatic and psychological criteria of school readiness.[30][31][clarification needed]

Supporting structures

Histologic slide of tooth erupting into the mouth
A: tooth
B: gingiva
C: bone
D: periodontal ligaments

The

gingiva
or gum, which is readily visible in the mouth.

Periodontal ligaments

The

periodontal ligament is a specialized connective tissue that attaches the cementum of a tooth to the alveolar bone. This tissue covers the root of the tooth within the bone. Each ligament has a width of 0.15–0.38mm, but this size decreases over time.[33] The functions of the periodontal ligaments include attachment of the tooth to the bone, support for the tooth, formation and resorption of bone during tooth movement, sensation, and eruption.[29] The cells of the periodontal ligaments include osteoblasts, osteoclasts, fibroblasts, macrophages, cementoblasts, and epithelial cell rests of Malassez.[34] Consisting of mostly Type I and III collagen, the fibers are grouped in bundles and named according to their location. The groups of fibers are named alveolar crest, horizontal, oblique, periapical, and interradicular fibers.[35] The nerve supply generally enters from the bone apical to the tooth and forms a network around the tooth toward the crest of the gingiva.[36]
When pressure is exerted on a tooth, such as during chewing or biting, the tooth moves slightly in its socket and puts tension on the periodontal ligaments. The nerve fibers can then send the information to the central nervous system for interpretation.

Alveolar bone

The

tension
from periodontal ligaments attached to a tooth moving away from it has a high number of osteoblasts, resulting in bone formation.

Gingiva

The

stratified squamous tissue on the gingiva which touches but is not attached to the tooth.[39]

Tooth decay

See also: Tooth pathology

Plaque

Main article: Dental plaque

Plaque is a

periodontal problems such as gingivitis. Given time, plaque can mineralize along the gingiva, forming tartar. The microorganisms that form the biofilm are almost entirely bacteria (mainly streptococcus and anaerobes), with the composition varying by location in the mouth.[41] Streptococcus mutans
is the most important bacterium associated with dental caries.

Certain bacteria in the mouth live off the remains of foods, especially sugars and starches. In the absence of oxygen they produce lactic acid, which dissolves the calcium and phosphorus in the enamel.[15][42] This process, known as "demineralisation", leads to tooth destruction. Saliva gradually neutralises the acids, which causes the pH of the tooth surface to rise above the critical pH, typically considered to be 5.5. This causes remineralisation, the return of the dissolved minerals to the enamel. If there is sufficient time between the intake of foods then the impact is limited and the teeth can repair themselves. Saliva is unable to penetrate through plaque, however, to neutralize the acid produced by the bacteria.

Caries (cavities)

Advanced tooth decay on a premolar
Main article:
Dental caries

Dental caries (cavities), described as "tooth decay", is an infectious disease which damages the structures of teeth.

chronic childhood disease, being at least five times more common than asthma.[46] Countries that have experienced an overall decrease in cases of tooth decay continue to have a disparity in the distribution of the disease.[47] Among children in the United States and Europe, 60–80% of cases of dental caries occur in 20% of the population.[48]

Tooth decay is caused by certain types of acid-producing bacteria which cause the most damage in the presence of

fermentable carbohydrates such as sucrose, fructose, and glucose.[49][50] The resulting acidic levels in the mouth affect teeth because a tooth's special mineral content causes it to be sensitive to low pH. Depending on the extent of tooth destruction, various treatments can be used to restore teeth to proper form, function, and aesthetics, but there is no known method to regenerate large amounts of tooth structure. Instead, dental health organizations advocate preventive and prophylactic measures, such as regular oral hygiene and dietary modifications, to avoid dental caries.[51]

Tooth care

Oral hygiene

Toothbrushes are commonly used to help clean teeth.
Main article: Oral hygiene

Oral hygiene is the practice of keeping the mouth clean and is a means of preventing dental caries,

tooth scaling
, using various instruments or devices to loosen and remove deposits from teeth.

The purpose of cleaning teeth is to remove plaque, which consists mostly of bacteria.

gum line, where periodontal disease
often begins and could develop caries.

Electric toothbrushes are a popular aid to oral hygiene. A user without disabilities, with proper training in manual brushing, and with good motivation, can achieve standards of oral hygiene at least as satisfactory as the best electric brushes, but untrained users rarely achieve anything of the kind. Not all electric toothbrushes are equally effective and even a good design needs to be used properly for best effect, but: "Electric toothbrushes tend to help people who are not as good at cleaning teeth and as a result have had oral hygiene problems."[53] The most important advantage of electric toothbrushes is their ability to aid people with dexterity difficulties, such as those associated with rheumatoid arthritis.

Protective treatments

Fluoride therapy is often recommended to protect against dental caries. Water fluoridation and fluoride supplements decrease the incidence of dental caries. Fluoride helps prevent dental decay by binding to the hydroxyapatite crystals in enamel.[54] The incorporated fluoride makes enamel more resistant to demineralization and thus more resistant to decay.[29] Topical fluoride, such as a fluoride toothpaste or mouthwash, is also recommended to protect teeth surfaces. Many dentists include application of topical fluoride solutions as part of routine cleanings.

Dental sealants are another preventive therapy often used to provide a barrier to bacteria and decay on the surface of teeth. Sealants can last up to ten years and are primarily used on the biting surfaces of molars of children and young adults, especially those who may have difficulty brushing and flossing effectively. Sealants are applied in a dentist's office, sometimes by a dental hygienist, in a procedure similar in technique and cost to a fluoride application.

Flossing with twin line floss picks eliminates all future cavities after use for a few weeks.

Restorations

A restored premolar

After a tooth has been damaged or destroyed,

artificial crown or a veneer
, to restore the involved tooth.

When a tooth is lost, dentures, bridges, or implants may be used as replacements.[56] Dentures are usually the least costly whereas implants are usually the most expensive. Dentures may replace complete arches of the mouth or only a partial number of teeth. Bridges replace smaller spaces of missing teeth and use adjacent teeth to support the restoration. Dental implants may be used to replace a single tooth or a series of teeth. Though implants are the most expensive treatment option, they are often the most desirable restoration because of their aesthetics and function. To improve the function of dentures, implants may be used as support.[57]

Abnormalities

A broken upper front tooth showing the pink of the pulp

Tooth abnormalities may be categorized according to whether they have environmental or developmental causes.[58] While environmental abnormalities may appear to have an obvious cause, there may not appear to be any known cause for some developmental abnormalities. Environmental forces may affect teeth during development, destroy tooth structure after development, discolor teeth at any stage of development, or alter the course of tooth eruption. Developmental abnormalities most commonly affect the number, size, shape, and structure of teeth.

Environmental

Alteration during tooth development

Tooth abnormalities caused by environmental factors during tooth development have long-lasting effects. Enamel and dentin do not regenerate after they mineralize initially.

antineoplastic
therapy.

Destruction after development

Tooth destruction from processes other than

external resorption
, when caused by cells in the periodontal ligament.

Discoloration

Main article: Tooth discoloration
Discolored teeth

Discoloration of teeth may result from bacteria stains, tobacco, tea, coffee, foods with an abundance of

Erythroblastosis fetalis and biliary atresia are diseases which may cause teeth to appear green from the deposition of biliverdin. Also, trauma may change a tooth to a pink, yellow, or dark gray color. Pink and red discolorations are also associated in patients with lepromatous leprosy. Some medications, such as tetracycline
antibiotics, may become incorporated into the structure of a tooth, causing intrinsic staining of the teeth.

Alteration of eruption

Tooth eruption may be altered by some environmental factors. When eruption is prematurely stopped, the tooth is said to be

tumors, cysts, trauma, and thickened bone or soft tissue. Tooth ankylosis
occurs when the tooth has already erupted into the mouth but the cementum or dentin has fused with the alveolar bone. This may cause a person to retain their primary tooth instead of having it replaced by a permanent one.

A technique for altering the natural progression of eruption is employed by

orthodontists
who wish to delay or speed up the eruption of certain teeth for reasons of space maintenance or otherwise preventing crowding and/or spacing. If a primary tooth is extracted before its succeeding permanent tooth's root reaches ⅓ of its total growth, the eruption of the permanent tooth will be delayed. Conversely, if the roots of the permanent tooth are more than ⅔ complete, the eruption of the permanent tooth will be accelerated. Between ⅓ and ⅔, it is unknown exactly what will occur to the speed of eruption.

Developmental

Abnormality in number

  • Anodontia is the total lack of tooth development.
  • Hyperdontia is the presence of a higher-than-normal number of teeth.
  • Hypodontia is the lack of development of one or more teeth.
    • Oligodontia may be used to describe the absence of 6 or more teeth.

Some systemic disorders which may result in hyperdontia include

Gorlin syndrome.[72]

Abnormality in size

  • Microdontia is a condition where teeth are smaller than the usual size.
  • Macrodontia is where teeth are larger than the usual size.

Microdontia of a single tooth is more likely to occur in a

hemifacial hyperplasia
.

Abnormality in shape

The fusion of two deciduous teeth
  • Gemination
    occurs when a developing tooth incompletely splits into the formation of two teeth.
  • Fusion is the union of two adjacent teeth during development.
  • Concrescence is the fusion of two separate teeth only in their cementum.
  • Accessory
    cusps are additional cusps on a tooth and may manifest as a Talon cusp, Cusp of Carabelli, or Dens evaginatus
    .
  • Dens invaginatus, also called Dens in dente, is a deep invagination in a tooth causing the appearance of a tooth within a tooth.
  • Ectopic enamel is enamel found in an unusual location, such as the root of a tooth.
  • Triple X syndrome, and XYY syndrome.[73]
  • Hypercementosis is excessive formation of cementum, which may result from trauma, inflammation, acromegaly, rheumatic fever, and Paget's disease of bone.[73]
  • A dilaceration is a bend in the root which may have been caused by trauma to the tooth during formation.
  • Supernumerary roots
    is the presence of a greater number of roots on a tooth than expected

Cleft lip and palate and their association with dental anomalies

There are many types of dental anomalies seen in cleft lip and palate (CLP) patients. Both sets of dentition may be affected; however, they are commonly seen in the affected side. Most frequently, missing teeth, supernumerary or discoloured teeth can be seen; however, enamel dysplasia, discolouration and delayed root development are also common. In children with cleft lip and palate, the lateral incisor in the alveolar cleft region has the highest prevalence of dental developmental disorders;[74] this condition may be a cause of tooth crowding.[75] This is important to consider in order to correctly plan treatment keeping in mind considerations for function and aesthetics. By correctly coordinating management invasive treatment procedures can be prevented resulting in successful and conservative treatment.

There have been a plethora of research studies to calculate prevalence of certain dental anomalies in CLP populations however a variety of results have been obtained.

In a study evaluating dental anomalies in Brazilian cleft patients, male patients had a higher incidence of CLP, agenesis, and supernumerary teeth than did female patients. In cases of complete CLP, the left maxillary lateral incisor was the most commonly absent tooth. Supernumerary teeth were typically located distal to the cleft.[76] In a study of Jordanian subjects, the prevalence of dental anomaly was higher in CLP patients than in normal subjects. Missing teeth were observed in 66.7% of patients, with maxillary lateral incisor as the most frequently affected tooth. Supernumerary teeth were observed in 16.7% of patients; other findings included microdontia (37%), taurodontism (70.5%), transposition or ectopic teeth (30.8%), dilacerations (19.2%), and hypoplasia (30.8%). The incidence of microdontia, dilaceration, and hypoplasia was significantly higher in bilateral CLP patients than in unilateral CLP patients, and none of the anomalies showed any significant sexual dimorphism.[77]

It is therefore evident that patients with cleft lip and palate may present with a variety of dental anomalies. It is essential to assess the patient both clinically and radiographically in order to correctly treat and prevent progression of any dental problems. It is also useful to note that patients with a cleft lip and palate automatically score a 5 on the IOTN ( index for orthodontic need) and therefore are eligible for orthodontic treatment, liaising with an orthodontist is vital in order coordinate and plan treatment successfully.

Abnormality in structure

See also

Lists

  • List of basic dentistry topics
  • List of oral health and dental topics

References

Notes

  1. ^ Stay, Flora. "How Your Teeth Affect Your Digestive System". TotalHealth Magazine. Retrieved 27 August 2022.
  2. ISBN 978-0-8067-0323-7
    .
  3. ^ Ash 2003, p. 6
  4. ^ Cate 1998, p. 3
  5. ^ Ash 2003, p. 9
  6. ^ "Impacted wisdom teeth". Mayo Clinic. Retrieved 5 March 2022.
  7. S2CID 76662620
    .
  8. ^ Ross 2002, p. 441
  9. ^ Cate 1998, p. 1
  10. ^ a b Cate 1998, p. 219
  11. ^ "Tooth enamel | Drug Discrimination Database".
  12. ^ a b Johnson, Clarke (1998). "Biology of the Human Dentition Archived 2015-10-30 at the Wayback Machine". uic.edu.
  13. ^ Cate 1998, p. 198
  14. ^ "Severe Plane-Form Enamel Hypoplasia in a Dentition from Roman Britain". ResearchGate. Retrieved 2019-01-09.
  15. ^ a b c Ross 2002, p. 448
  16. ^ a b c Cate 1998, p. 150
  17. ^ Ross 2002, p. 450
  18. ^ Cate 1998, p. 152
  19. S2CID 4798656
    .
  20. ^ "Tertiary Dentine Frequencies in Extant Great Apes and Fossil Hominins". ResearchGate. Retrieved 2019-03-28.
  21. ^ Cate 1998, p. 236
  22. ^ Cate 1998, p. 241
  23. ^ Ross 2002, p. 451
  24. ISBN 0-7216-9160-9
    .
  25. ^ Cate 1998, p. 95
  26. ^ a b Cate 1998, p. 81
  27. ^ a b c Lab Exercises: Tooth development. University of Texas Medical Branch.
  28. ^ Cate 1998, pp. 86 and 102.
  29. ^ a b c d Ross 2002, p. 453
  30. ^ Kranich, Ernst-Michael (1990) "Anthropologie", in F. Bohnsack and E-M Kranich (eds.), Erziehungswissenschaft und Waldorfpädagogik, Reihe Pädagogik Beltz, Weinheim, p. 126, citing Frances Ilg and Louise Bates Ames (Gesell Institute), School Readiness, p. 236 ff
  31. PMID 264640
    . ...the loss of the first deciduous tooth can serve as a definite indicator of a male child's readiness for reading and schoolwork
  32. ^ a b Ross 2002, p. 452
  33. ^ Cate 1998, p. 256
  34. ^ Cate 1998, p. 260
  35. ^ Listgarten, Max A. "Histology of the Periodontium: Principal fibers of the periodontal ligament," University of Pennsylvania and Temple University. Created May 8, 1999, revised 16 January 2007.
  36. ^ Cate 1998, p. 270
  37. ^ Cate 1998, p. 274
  38. ^ Cate 1998, pp. 247 and 248
  39. ^ Cate 1998, p. 280
  40. ^ "Oral Health Topics: Plaque", American Dental Association.
  41. ^ Introduction to dental plaque Archived 2011-08-27 at the Wayback Machine, Leeds Dental Institute.
  42. ^ Ophardt, Charles E. "Sugar and tooth decay", Elmhurst College.
  43. ^ Dental Cavities, MedlinePlus Medical Encyclopedia.
  44. PMID 23659234
    .
  45. PMID 2129621
    .
  46. ^ Healthy People: 2010. Healthy People.gov.
  47. ^ "Dental caries", from the Disease Control Priorities Project.
  48. PMID 14522753
    .
  49. PMID 6959931
    .
  50. PMID 6358295
    .
  51. ^ a b Oral Health Topics: Cleaning your teeth and gums. American Dental Association.
  52. ^ Introduction to Dental Plaque Archived 2011-08-27 at the Wayback Machine. Leeds Dental Institute.
  53. ^ Thumbs down for electric toothbrush, BBC News, January 21, 2003.
  54. ^ Cate 1998, p. 223
  55. ^ "Oral Health Topics: Dental Filling Options". ada.org.
  56. ^ "Prosthodontic Procedures", The American College of Prosthodontists.
  57. ^ "Dental Implants", American Association of Oral and Maxillofacial Surgeons.
  58. ^ Neville 2002, p. 50.
  59. ^ Ash 2003, p. 31
  60. ^
    PMID 26097340
    .
  61. ^ Neville 2002, p. 51
  62. ^ a b Dental Enamel Defects and Celiac Disease Archived 2016-03-05 at the Wayback Machine National Institute of Health (NIH)
  63. PMID 23265166
    .
  64. PMID 20212408
    .
  65. ^ Syphilis: Complications, Mayo Clinic.
  66. ^ "Loss of Tooth Structure", American Dental Hygiene Association.
  67. ^ "Abnormalities of Teeth", University of Missouri-Kansas City School of Dentistry.
  68. PMID 15055615. Archived from the original
    (PDF) on September 7, 2006.
  69. ^ Neville 2002, p. 63
  70. ^ Neville 2002, p. 66
  71. ^ Neville 2002, p. 70
  72. ^ Neville 2002, p. 69
  73. ^ a b Neville 2002, p. 85
  74. S2CID 23991279
    .
  75. ^ "Dental Crowding: Causes and Treatment Options". Orthodontics Australia. 2020-06-29. Retrieved 2021-02-06.
  76. doi:10.1590/S1980-65232010000200006
    .
  77. S2CID 7220626
    .
  78. ^ Amelogenesis imperfecta, Genetics Home Reference, a service of the U.S. National Library of Medicine.
  79. ^ Dentinogenesis imperfecta, Genetics Home Reference, a service of the U.S. National Library of Medicine.
  80. PMID 17049109
    .
  81. ^ ASDC Journal of Dentistry for Children, Volume 48. American Society of Dentistry for Children, 1980. p. 266

Sources

External links

Look up tooth in Wiktionary, the free dictionary.
Wikimedia Commons has media related to Human teeth.
Retrieved from "https://en.wikipedia.org/w/index.php?title=Human_tooth&oldid=1215346715"