Cementum: Difference between revisions

Cementum
Cementum
	Basic tooth anatomy, showing cementum
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Latin	caementum
MeSH	D003739
TA98	A05.1.03.057; A03.1.03.007
TA2	1612
FMA	55630
	Anatomical terminology [edit on Wikidata]

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Cementum^[1] is a specialized calcified substance covering the root of a tooth. The cementum is the part of the periodontium that attaches the teeth to the alveolar bone by anchoring the periodontal ligament.^[2]^[3]

Structure

The **cementum** is the surface layer of the tooth root, covering the dentin (which is labeled B). Rather than being a passive entity like paint on a wall, cementum is a dynamic entity within the periodontium. It is attached to the alveolar bone *(C)* by the fibers of the periodontal ligament and to the soft tissue of the gingiva by the gingival fibers *(H)*.

The cells of cementum are the entrapped cementoblasts, the cementocytes. Each cementocyte lies in its lacuna, similar to the pattern noted in bone. These lacunae also have canaliculi or canals. Unlike those in bone, however, these canals in cementum do not contain nerves, nor do they radiate outward. Instead, the canals are oriented toward the periodontal ligament and contain cementocytic processes that exist to diffuse nutrients from the ligament because it is vascularized.

After the apposition of cementum in layers, the cementoblasts that do not become entrapped in cementum line up along the cemental surface along the length of the outer covering of the periodontal ligament. These cementoblasts can form subsequent layers of cementum if the tooth is injured.

Sharpey fibers are part of the principal collagenous fibers of the periodontal ligament embedded in the cementum and alveolar bone to attach the tooth to the alveolus.^[3]

If cementum can be observed on teeth, it can imply that the roots are exposed, showing that the clinical crown (the exposed part of the tooth) is bigger than the anatomical crown (the surface of the tooth covered by enamel).^[4] This is often due to gingival recession and may be an indication of periodontal disease.^[5]

Cementoenamel junction

The cementum joins the enamel to form the cementoenamel junction (CEJ), which is referred to as the cervical line.

Three possible types of transitional interfaces may be present at the CEJ. The traditional view was that certain interfaces dominated in certain oral cavities. The CEJ may exhibit all of these interfaces in an individual's oral cavity, and there is even considerable variation when one tooth is traced circumferentially.^[3]

Dentinocemental junction

When the cementoid reaches the full thickness needed, the cementoid surrounding the cementocytes becomes mineralized, or matured, and is then considered cementum. The dentinocemental junction (DCJ) is formed because of the apposition of cementum over the dentin.^[6]^[7] This interface is not as defined, either clinically or histologically, as that of the dentinoenamel junction (DEJ), given that cementum and dentin are of common embryological background, unlike that of enamel and dentin.^[3]

The dentinocemental junction (DCJ) is a relatively smooth area in the permanent tooth, and attachment of cementum to the dentin is firm but not understood completely.^[8]

Types

The different categories of cementum are based on the presence or absence of cementocytes, as well as whether the collagen fibres are extrinsic or intrinsic. It is thought that fibroblasts, and some cementoblasts, secrete extrinsic fibres, but only cementoblasts secrete intrinsic fibres.^[9] The extrinsic fibres within acellular extrinsic fibre cementum, travel perpendicular to the surface of the root and allow the tooth to attach to the alveolar bone by the periodontal ligament (PDL), continuous with the cementodentinal junction (CDJ).^[10] Acellular cementum only contains extrinsic collagen fibres. Whereas, cellular cementum is quite thick and contains both extrinsic and intrinsic collagen fibres.^[10] The first cementum to be formed during tooth development is acellular extrinsic fibre cementum.^[11]^[12] The acellular layer of cementum is living tissue that does not incorporate cells into its structure and usually predominates on the coronal half of the root; cellular cementum occurs more frequently on the apical half.^[8] In summary, the main types of cementum are as follows: acellular afibrillar cementum (AAC), acellular extrinsic fibres cementum (AEFC), cellular intrinsic fibres cementum (CIFC) and mixed stratified cementum (MSC) which displays both cellular and acellular cementum.^[10]^[13]

Cellular cementum contains cells and is the medium of attachment of collagen fibres to the alveolar bone. It is also responsible for minor repair of any resorption by continued deposition to keep the attachment apparatus intact.^[14] Acellular cementum does not contain cells and has a main purpose of adaptive function.^[15]

Composition

Cementum is slightly softer than dentin and consists of about 45% to 50% inorganic material (hydroxylapatite) by weight and 50% to 55% organic matter and water by weight.^[16] The organic portion is composed primarily of collagen and proteoglycans.^[17] Cementum is avascular, receiving its nutrition through its own imbedded cells from the surrounding vascular periodontal ligament.^[3]

The cementum is light yellow and slightly lighter in color than dentin. It has the highest fluoride content of all mineralized tissue. Cementum also is permeable to a variety of materials. It is formed continuously throughout life because a new layer of cementum is deposited to keep the attachment intact as the superficial layer of cementum ages. Cementum on the root ends surrounds the apical foramen and may extend slightly onto the inner wall of the pulp canal.

Development

Cementum is secreted by cells called cementoblasts within the root of the tooth and is thickest at the root apex (the end of the root where the nerves and blood vessels enter the tooth). These cementoblasts develop from undifferentiated mesenchymal cells in the connective tissue of the dental follicle or sac. Cementoblasts produces cementum in a rhythmic manner on intervals indicating periods of activity and periods of rest, producing so-called incremental lines of Salter. Incremental lines of Salter are the only incremental lines in the tooth that are hypercalcified, due to the fact that there is a much smaller organic portion (collagen fibers) than inorganic portion (hydroxyapatite crystals) of cementum, so when the cementoblasts rest they leave a space for the inorganic portion. Conversely, in enamel ameloblasts (incremental lines of Retzius) and dentin odontoblasts (incremental lines of von Ebner), the inorganic portion is much greater than the organic portion, so when ameloblasts and odontoblasts rest, they leave a space for the organic portion and become hypocalcified.^[8]

Unlike ameloblasts and odontoblasts, which leave no cellular bodies in their secreted products, during the later steps within the stage of apposition, many of the cementoblasts become entrapped by the cementum they produce, becoming cementocytes. Thus again, cementum is more similar to alveolar bone, with its osteoblasts becoming entrapped osteocytes.^[3]

Cementum is capable of repairing itself to a limited degree, but cannot regenerate. It is not resorbed under normal conditions.^[11]

Clinical significance

Some root resorption of the apical portion of the root may occur if orthodontic pressures are excessive and movement is too fast. Some experts also agree on a third type of cementum, afibrillar cementum, which sometimes extends onto the enamel of the tooth.
The excessive buildup of cementum on the roots of a tooth is a pathological condition known as hypercementosis. Cementum thickness can increase on the root end to compensate for attritional wear of the occlusal/incisal surface and passive eruption of the tooth.^[18]
When cementum is exposed through gingival recession, it quickly undergoes abrasion by mechanical friction because of its low mineral content and thinness. The exposure of the deeper dentin can lead to problems such as extrinsic staining and dentinal hypersensitivity.^[3]
The incidence of cemental caries increases in older adults as gingival decline occurs from either trauma or periodontal illness. It is a chronic condition that forms a large, shallow lesion and slowly invades first the root's cementum and then dentin to cause a chronic infection of the pulp. Because dental pain is a late finding, many lesions are not detected early, resulting in restorative obstacles and increased tooth loss.^[3]
Cementicles are small, spherical or ovoid calcified masses embedded within or attached to the cementum layer on the root surface of a tooth, or lying free within the periodontal ligament.^[19]^[20]
Cemental spurs can be found at or near the CEJ. These are symmetrical spheres of cementum attached to the cemental root surface, similar to enamel pearls. Cemental spurs result from irregular deposition of cementum on the root. They can present some clinical problems in differentiation from calculus and may be noted on radiographs; yet, because they are hard dental tissue, they are not easily removed, and thus may also interfere with periodontal treatment.^[3]

DNA studies

A 2010 archeological study has found that cementum has five times the amount of mitochondrial DNA compared to dentin, which is commonly sampled.^[21] Teeth are increasingly utilized as a source of nuclear DNA to aid identification of human remains. DNA extraction and the results of genetic analysis from the tissue are extremely variable and to some extent unpredictable. However, the quantity of DNA available in dentin is affected by age and dental disease, whereas that in cementum is not.^[22]

References

^ "Cementum". DentalFind. 2007-01-01.
^ Bath-Balogh M, Fehrenbach MJ (10 December 2010). Illustrated Dental Embryology, Histology, and Anatomy. Elsevier Health Sciences. p. 170. ISBN 978-1-4377-2934-4.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Illustrated Dental Embryology, Histology, and Anatomy, Bath-Balogh and Fehrenbach, Elsevier, 2011, page 170.
^ Hand AR (2015). Fundamentals of Oral Histology and Physiology. John Wiley & Sons Incorporated. ISBN 978-1-118-34291-6.
^ "Gum Disease Symptoms | Perio.org". www.perio.org. Retrieved 2019-12-11.
^ Jang, Andrew T.; Lin, Jeremy D.; Choi, Ryan M.; Choi, Erin M.; Seto, Melanie L.; Ryder, Mark I.; Gansky, Stuart A.; Curtis, Donald A.; Ho, Sunita P. (2014). "Adaptive properties of human cementum and cementum dentin junction with age". Journal of the Mechanical Behavior of Biomedical Materials. 39: 184–196. doi:10.1016/j.jmbbm.2014.07.015. ISSN 1751-6161. PMC 4265544. PMID 25133753.
^ "nixon dental". Retrieved 2023-06-23.
^ ^a ^b ^c Bosshardt DD, Selvig KA (February 1997). "Dental cementum: the dynamic tissue covering of the root" (PDF). Periodontology 2000. 13: 41–75. doi:10.1111/j.1600-0757.1997.tb00095.x. PMID 9567923.
^ Yamamoto T, Hasegawa T, Yamamoto T, Hongo H, Amizuka N (August 2016). "Histology of human cementum: Its structure, function, and development". The Japanese Dental Science Review. 52 (3): 63–74. doi:10.1016/j.jdsr.2016.04.002. PMC 5390338. PMID 28408958.
^ ^a ^b ^c Colard T, Falgayrac G, Bertrand B, Naji S, Devos O, Balsack C, et al. (2016). "Correction: New Insights on the Composition and the Structure of the Acellular Extrinsic Fiber Cementum by Raman Analysis". PLOS ONE. 12 (3): e0174080. doi:10.1371/journal.pone.0174080. PMC 5345870. PMID 28282444.
^ ^a ^b Nanci A (2013). Ten Cate's Oral Histology (8 ed.). Elsevier. pp. 205–207. ISBN 978-0-323-07846-7.
^ AAP 2010 In-Service Examination, question A-9
^ Gonçalves, Patricia Furtado; Sallum, Enilson Antonio; Sallum, Antonio Wilson; Casati, Márcio Zaffalon; Toledo, Sérgio de; Junior, Francisco Humberto Nociti (2005-12-31). "Dental cementum reviewed: development, structure, composition, regeneration and potential functions". {{cite journal}}: Cite journal requires |journal= (help)
^ Ghosh S (2019). Cementum. Germany: SPS. ISBN 978-6202317184.
^ Ehtisham M (2016). Cementum. LAP Lambert Academic Publishing Mai. ISBN 978-3659879753.
^ American Academy of Periodontology 2010 In-Service Exam, question A-38
^ Kumar G (15 Jul 2011). Orban's Oral Histology & Embryology (13th ed.). Elsevier India. p. 152. ISBN 9788131228197. Retrieved 1 December 2014.
^ Listgarten MA. "Histology of the Periodontium - Cementum". University of Pennsylvania and Temple University. Archived from the original on 9 July 2013.
^ Chiego Jr. DJ (14 April 2014). Essentials of Oral Histology and Embryology: A Clinical Approach. Elsevier Health Sciences. p. 133. ISBN 978-0-323-29100-2.
^ Bath-Balogh M, Fehrenbach MJ (10 December 2010). Illustrated Dental Embryology, Histology, and Anatomy. Elsevier Health Sciences. p. 174. ISBN 978-1-4377-2934-4.
^ Adler CJ, Haak W, Donlon D, Cooper A (May 2011). "Genographic Consortium. Survival and recovery of DNA from ancient teeth and bones". Journal of Archaeological Science. 38 (5): 956–64. doi:10.1016/j.jas.2010.11.010.
^ Higgins D, Kaidonis J, Townsend G, Hughes T, Austin JJ (October 2013). "Targeted sampling of cementum for recovery of nuclear DNA from human teeth and the impact of common decontamination measures". Investigative Genetics. 4 (1): 18. doi:10.1080/00450618.2011.583278. PMC 3853689. PMID 24139166. S2CID 85182819.

@@ Line 1: / Line 1: @@
+{{Short description|Specialized calcified substance covering the root of a tooth}}
 {{Infobox anatomy
 | Name        = Cementum
 | Latin       = caementum
-| Image       = Periodontium.svg
+| Image       = Basic anatomy tooth.jpg
+| Caption     = Basic tooth anatomy, showing cementum
-| Caption     = The '''cementum''' is the surface layer of the tooth root, covering the [[dentine]] (which is labeled ''B''). Rather than being a passive entity like paint on a wall, cementum is a dynamic entity within the [[periodontium]].  It is attached to the [[alveolar bone]] ''(C)'' by the fibers of the [[periodontal ligament]] and to the soft tissue of the [[gingiva]] by the [[gingival fibers]] ''(H)''.
 | Image2      =
 | Caption2    =
@@ Line 12: / Line 13: @@
 | title = Cementum
 | publisher = DentalFind
-| date  = 2007-01-01}}</ref> is a specialized calcified substance covering the root of a [[tooth]]. The cementum is the part of the [[periodontium]] that attaches the teeth to the [[alveolar bone]] by anchoring the [[periodontal ligament]].<ref name=":0">Illustrated Dental Embryology, Histology, and Anatomy, Bath-Balogh and Fehrenbach, Elsevier, 2011, page 170.</ref>
+| date  = 2007-01-01}}</ref> is a specialized calcified substance covering the root of a [[tooth]]. The cementum is the part of the [[periodontium]] that attaches the teeth to the [[alveolar bone]] by anchoring the [[periodontal ligament]].<ref name="Bath-Balogh_2010">{{cite book| vauthors = Bath-Balogh M, Fehrenbach MJ|title=Illustrated Dental Embryology, Histology, and Anatomy|url=https://books.google.com/books?id=uPMLBAAAQBAJ&pg=PA170 |date=10 December 2010|publisher=Elsevier Health Sciences|isbn=978-1-4377-2934-4|page=170}}</ref><ref name=":0">Illustrated Dental Embryology, Histology, and Anatomy, Bath-Balogh and Fehrenbach, Elsevier, 2011, page 170.</ref>
-==Structure==
+== Structure ==
-[[File:Human tooth diagram-en.svg|thumb|Cementum situated around a human molar]]
+[[File:Human tooth diagram-en.svg|thumb|400px|Cementum situated around a human molar]]
+[[File:Periodontium.svg|thumb|The '''cementum''' is the surface layer of the tooth root, covering the [[dentin]] (which is labeled ''B''). Rather than being a passive entity like paint on a wall, cementum is a dynamic entity within the [[periodontium]].  It is attached to the [[alveolar bone]] ''(C)'' by the fibers of the [[periodontal ligament]] and to the soft tissue of the [[gingiva]] by the [[gingival fibers]] ''(H)''.]]
 The cells of cementum are the entrapped cementoblasts, the cementocytes. Each cementocyte lies in its [[Wikt:lacuna|lacuna]], similar to the pattern noted in bone. These lacunae also have canaliculi or canals. Unlike those in bone, however, these canals in cementum do not contain nerves, nor do they radiate outward. Instead, the canals are oriented toward the periodontal ligament and contain cementocytic processes that exist to diffuse nutrients from the ligament because it is vascularized.
@@ Line 22: / Line 24: @@
 [[Sharpey's fibers|Sharpey fibers]] are part of the principal collagenous fibers of the [[periodontal ligament]] embedded in the cementum and [[alveolar bone]] to attach the tooth to the alveolus.<ref name=":0"/>
-If cementum can be observed on teeth, it can imply that the roots are exposed, showing that the clinical crown (the exposed part of the tooth) is bigger than the anatomical crown (the surface of the tooth covered by enamel).<ref>{{Cite book|title=Fundamentals of Oral Histology and Physiology.|last=Hand|first=AR|publisher=John Wiley & Sons Incorporated|year=2015|isbn=978-1-118-34291-6|location=|pages=}}</ref> This is often due to [[Gums|gingival]] recession and may be an indication of [[periodontal disease]]<ref>{{Cite web|url=https://www.perio.org/consumer/gum-disease-symptoms.htm|title=Gum Disease Symptoms {{!}} Perio.org|website=www.perio.org|access-date=2019-12-11}}</ref>[[Periodontal disease|.]]
+If cementum can be observed on teeth, it can imply that the roots are exposed, showing that the clinical crown (the exposed part of the tooth) is bigger than the anatomical crown (the surface of the tooth covered by enamel).<ref>{{Cite book|title=Fundamentals of Oral Histology and Physiology.| vauthors = Hand AR |publisher=John Wiley & Sons Incorporated|year=2015|isbn=978-1-118-34291-6}}</ref> This is often due to [[Gums|gingival]] recession and may be an indication of [[periodontal disease]].<ref>{{Cite web|url=https://www.perio.org/consumer/gum-disease-symptoms.htm|title=Gum Disease Symptoms {{!}} Perio.org|website=www.perio.org|access-date=2019-12-11}}</ref>
 ===Cementoenamel junction===
@@ Line 31: / Line 33: @@
 ===Dentinocemental junction===
-When the cementoid reaches the full thickness needed, the cementoid surrounding the cementocytes becomes mineralized, or matured, and is then considered cementum. Because of the apposition of cementum over the dentin, the dentinocemental junction (DCJ) is formed. This interface is not as defined, either clinically or histologically, as that of the dentinoenamel junction (DEJ), given that cementum and dentin are of common embryological background, unlike that of enamel and dentin.<ref name=":0"/>
+When the cementoid reaches the full thickness needed, the cementoid surrounding the cementocytes becomes mineralized, or matured, and is then considered cementum. The dentinocemental junction (DCJ) is formed because of the apposition of cementum over the dentin.<ref>{{Cite journal |title=Adaptive properties of human cementum and cementum dentin junction with age |journal=Journal of the Mechanical Behavior of Biomedical Materials |year=2014 |volume=39 |pages=184–196 |doi=10.1016/j.jmbbm.2014.07.015 |issn=1751-6161 |pmc=4265544 |pmid=25133753 |last1=Jang |first1=Andrew T. |last2=Lin |first2=Jeremy D. |last3=Choi |first3=Ryan M. |last4=Choi |first4=Erin M. |last5=Seto |first5=Melanie L. |last6=Ryder |first6=Mark I. |last7=Gansky |first7=Stuart A. |last8=Curtis |first8=Donald A. |last9=Ho |first9=Sunita P. }}</ref><ref>{{Cite web |title=nixon dental |url=https://www.nixondental.com/ |access-date=2023-06-23}}</ref> This interface is not as defined, either clinically or histologically, as that of the dentinoenamel junction (DEJ), given that cementum and dentin are of common embryological background, unlike that of enamel and dentin.<ref name=":0"/>
-The dentinocemental junction (DCJ) is a relatively smooth area in the permanent tooth, and attachment of cementum to the dentin is firm but not understood completely.<ref name=":2">{{cite journal|authors=Dieter D. Bosshardt, Knut A. Selvig|title= Dental cementum: the dynamic tissue covering of the root|journal=Periodontol 2000|year= 1997|volume=13|pages=41–75|url=http://www.fodonto.uncu.edu.ar/upload/41-75.pdf|doi=10.1111/j.1600-0757.1997.tb00095.x|pmid= 9567923}}</ref>
+The dentinocemental junction (DCJ) is a relatively smooth area in the permanent tooth, and attachment of cementum to the dentin is firm but not understood completely.<ref name=":2">{{cite journal | vauthors = Bosshardt DD, Selvig KA | title = Dental cementum: the dynamic tissue covering of the root | journal = Periodontology 2000 | volume = 13 | pages = 41–75 | date = February 1997 | pmid = 9567923 | doi = 10.1111/j.1600-0757.1997.tb00095.x | url = http://www.fodonto.uncu.edu.ar/upload/41-75.pdf }}</ref>
 ===Types===
-The different categories of cementum are based on the presence or absence of cementocytes, as well as whether the [[collagen]] fibres are '''extrinsic''' or '''intrinsic'''. It is thought that [[fibroblast]]s, and some [[cementoblast]]s, secrete extrinsic fibres, but only cementoblasts secrete intrinsic fibres.<ref>{{Cite journal|last=Yamamoto|first=Tsuneyuki|last2=Hasegawa|first2=Tomoka|last3=Yamamoto|first3=Tomomaya|last4=Hongo|first4=Hiromi|last5=Amizuka|first5=Norio|date=August 2016|title=Histology of human cementum: Its structure, function, and development|journal=The Japanese Dental Science Review|volume=52|issue=3|pages=63–74|doi=10.1016/j.jdsr.2016.04.002|issn=1882-7616|pmc=5390338|pmid=28408958}}</ref> The extrinsic fibres within acellular extrinsic fibre cementum, travel perpendicular to the surface of the root and allow the tooth to attach to the alveolar bone by the periodontal ligament (PDL), continuous with the cementodentinal junction (CDJ).<ref name=":1">{{Cite journal|last=Colard|first=T.|date=2016|title=Correction: New Insights on the Composition and the Structure of the Acellular Extrinsic Fiber Cementum by Raman Analysis|url=|journal=PLOS ONE|volume= 12| issue = 3|pages=e0174080|pmid=28282444|doi=10.1371/journal.pone.0174080|pmc=5345870}}</ref> Acellular cementum only contains extrinsic collagen fibres. Whereas, cellular cementum is quite thick and contains both extrinsic and intrinsic collagen fibres.<ref name=":1" /> The first cementum to be formed during tooth development is acellular extrinsic fibre cementum.<ref name=":4" /><ref>AAP 2010 In-Service Examination, question A-9</ref> The acellular layer of cementum is living tissue that does not incorporate cells into its structure and usually predominates on the coronal half of the root; cellular cementum occurs more frequently on the apical half.<ref name=":2"/> In summary, the main types of cementum are as follows: Acellular Extrinsic Fibres Cementum (AEFC), Cellular Intrinsic Fibres Cementum (CIFC) and Mixed Stratified Cementum (MSC) which displays both cellular and acellular cementum.<ref name=":1" />
+The different categories of cementum are based on the presence or absence of cementocytes, as well as whether the [[collagen]] fibres are '''extrinsic''' or '''intrinsic'''. It is thought that [[fibroblast]]s, and some [[cementoblast]]s, secrete extrinsic fibres, but only cementoblasts secrete intrinsic fibres.<ref>{{cite journal | vauthors = Yamamoto T, Hasegawa T, Yamamoto T, Hongo H, Amizuka N | title = Histology of human cementum: Its structure, function, and development | journal = The Japanese Dental Science Review | volume = 52 | issue = 3 | pages = 63–74 | date = August 2016 | pmid = 28408958 | pmc = 5390338 | doi = 10.1016/j.jdsr.2016.04.002 }}</ref> The extrinsic fibres within acellular extrinsic fibre cementum, travel perpendicular to the surface of the root and allow the tooth to attach to the alveolar bone by the periodontal ligament (PDL), continuous with the cementodentinal junction (CDJ).<ref name=":1">{{cite journal | vauthors = Colard T, Falgayrac G, Bertrand B, Naji S, Devos O, Balsack C, Delannoy Y, Penel G | display-authors = 6 | title = Correction: New Insights on the Composition and the Structure of the Acellular Extrinsic Fiber Cementum by Raman Analysis | journal = PLOS ONE | volume = 12 | issue = 3 | pages = e0174080 | date = 2016 | pmid = 28282444 | pmc = 5345870 | doi = 10.1371/journal.pone.0174080 | doi-access = free }}</ref> Acellular cementum only contains extrinsic collagen fibres. Whereas, cellular cementum is quite thick and contains both extrinsic and intrinsic collagen fibres.<ref name=":1" /> The first cementum to be formed during tooth development is acellular extrinsic fibre cementum.<ref name=":4" /><ref>AAP 2010 In-Service Examination, question A-9</ref> The acellular layer of cementum is living tissue that does not incorporate cells into its structure and usually predominates on the coronal half of the root; cellular cementum occurs more frequently on the apical half.<ref name=":2"/> In summary, the main types of cementum are as follows: acellular afibrillar cementum (AAC), acellular extrinsic fibres cementum (AEFC), cellular intrinsic fibres cementum (CIFC) and mixed stratified cementum (MSC) which displays both cellular and acellular cementum.<ref name=":1" /><ref>{{Cite journal |last1=Gonçalves |first1=Patricia Furtado |last2=Sallum |first2=Enilson Antonio |last3=Sallum |first3=Antonio Wilson |last4=Casati |first4=Márcio Zaffalon |last5=Toledo |first5=Sérgio de |last6=Junior |first6=Francisco Humberto Nociti |date=2005-12-31 |title=Dental cementum reviewed: development, structure, composition, regeneration and potential functions |url=https://tspace.library.utoronto.ca/handle/1807/8570 |language=en-US}}</ref>
-Cellular cementum contains cells and is the medium of attachment of collagen fibres to the alveolar bone. It is also responsible for minor repair of any resorption by continued deposition to keep the attachment apparatus intact.<ref>{{Cite book|title=Cementum|last=Ghosh|first=Supratim|publisher=SPS|year=2019|isbn=978-6202317184|location=Germany|pages=}}</ref> Acellular cementum does not contain cells and has a main purpose of adaptive function.<ref>{{Cite book|title=Cementum|last=Ehtisham|first=Mohammad|publisher=LAP Lambert Academic Publishing Mai|year=2016|isbn=978-3659879753|location=|pages=}}</ref>
+Cellular cementum contains cells and is the medium of attachment of collagen fibres to the alveolar bone. It is also responsible for minor repair of any resorption by continued deposition to keep the attachment apparatus intact.<ref>{{Cite book |title=Cementum| vauthors = Ghosh S |publisher=SPS|year=2019|isbn=978-6202317184|location=Germany}}</ref> Acellular cementum does not contain cells and has a main purpose of adaptive function.<ref>{{Cite book|title=Cementum| vauthors = Ehtisham M |publisher=LAP Lambert Academic Publishing Mai|year=2016|isbn=978-3659879753}}</ref>
 ===Composition===
-Cementum is slightly softer than [[dentin]] and consists of about 45% to 50% inorganic material ([[hydroxylapatite]]) by weight and 50% to 55% [[organic matter]] and water by weight.<ref>American Academy of Periodontology 2010 In-Service Exam, question A-38</ref> The organic portion is composed primarily of [[collagen]] and [[proteoglycans]].<ref>{{cite book|last1=Kumar|first1=G.|title=Orban's Oral Histology & Embryology|date=15 Jul 2011|publisher=Elsevier India|isbn=9788131228197|page=152|edition=13th|url=https://books.google.com/?id=061EAwAAQBAJ&pg=PA152&lpg=PA152&dq=what+is+protein+polysaccharides+in+cementum#v=onepage&q=what%20is%20protein%20polysaccharides%20in%20cementum&f=false|accessdate=1 December 2014}}</ref> Cementum is avascular, receiving its nutrition through its own imbedded cells from the surrounding vascular [[periodontal ligament]].<ref name=":0"/>
+Cementum is slightly softer than [[dentin]] and consists of about 45% to 50% inorganic material ([[hydroxylapatite]]) by weight and 50% to 55% [[organic matter]] and water by weight.<ref>American Academy of Periodontology 2010 In-Service Exam, question A-38</ref> The organic portion is composed primarily of [[collagen]] and [[proteoglycans]].<ref>{{cite book| vauthors = Kumar G |title=Orban's Oral Histology & Embryology|date=15 Jul 2011|publisher=Elsevier India|isbn=9788131228197 |page=152| edition=13th |url=https://books.google.com/books?id=061EAwAAQBAJ&q=what+is+protein+polysaccharides+in+cementum&pg=PA152 |access-date=1 December 2014}}</ref> Cementum is avascular, receiving its nutrition through its own imbedded cells from the surrounding vascular [[periodontal ligament]].<ref name=":0"/>
 The cementum is light yellow and slightly lighter in color than [[dentin]]. It has the highest fluoride content of all mineralized tissue. Cementum also is permeable to a variety of materials. It is formed continuously throughout life because a new layer of cementum is deposited to keep the attachment intact as the superficial layer of cementum ages. Cementum on the root ends surrounds the apical foramen and may extend slightly onto the inner wall of the pulp canal.
@@ Line 47: / Line 49: @@
 ===Development===
 {{main|Cementogenesis}}
-Cementum is secreted by cells called [[cementoblasts]] within the root of the tooth and is thickest at the root apex. These cementoblasts develop from undifferentiated [[mesenchymal cell]]s in the connective tissue of the [[dental follicle]] or sac.<ref name=":2"/>
+Cementum is secreted by cells called [[cementoblasts]] within the root of the tooth and is thickest at the [[Root apex (dental)|root apex]] (the end of the root where the nerves and blood vessels enter the tooth). These cementoblasts develop from undifferentiated [[mesenchymal cell]]s in the connective tissue of the [[dental follicle]] or sac. Cementoblasts produces cementum in a rhythmic manner on intervals indicating periods of activity and periods of rest, producing so-called incremental lines of Salter. Incremental lines of Salter are the only incremental lines in the tooth that are hypercalcified, due to the fact that there is a much smaller organic portion (collagen fibers) than inorganic portion (hydroxyapatite crystals) of cementum, so when the cementoblasts rest they leave a space for the inorganic portion. Conversely, in enamel ameloblasts (incremental lines of Retzius) and dentin odontoblasts (incremental lines of von Ebner), the inorganic portion is much greater than the organic portion, so when ameloblasts and odontoblasts rest, they leave a space for the organic portion and become hypocalcified.<ref name=":2"/>
 Unlike [[ameloblast]]s and [[odontoblast]]s, which leave no cellular bodies in their secreted products, during the later steps within the stage of [[wiktionary:apposition|apposition]], many of the cementoblasts become entrapped by the cementum they produce, becoming cementocytes. Thus again, cementum is more similar to alveolar bone, with its osteoblasts becoming entrapped [[osteocyte]]s.<ref name=":0"/>
-Cementum is capable of repairing itself to a limited degree, but not regenerate. and is not resorbed under normal conditions.<ref name=":4">{{cite book|title=Ten Cate's Oral Histology|author=Nanci A|publisher=Elsevier|year=2013| pages=205–207|isbn=978-0-323-07846-7|edition=8}}</ref>
+Cementum is capable of repairing itself to a limited degree, but cannot regenerate. It is not resorbed under normal conditions.<ref name=":4">{{cite book|title=Ten Cate's Oral Histology|author=Nanci A|publisher=Elsevier|year=2013| pages=205–207|isbn=978-0-323-07846-7|edition=8}}</ref>
 ==Clinical significance==
-* Some [[root resorption]] of the apical portion of the root may occur, however, if orthodontic pressures are excessive and movement is too fast. Some experts also agree on a third type of cementum, ''afibrillar cementum'', which sometimes extends onto the enamel of the tooth.
+* Some [[root resorption]] of the apical portion of the root may occur if orthodontic pressures are excessive and movement is too fast. Some experts also agree on a third type of cementum, afibrillar cementum, which sometimes extends onto the enamel of the tooth.
-* The excessive buildup of cementum on the roots of a tooth is a pathological condition known as [[hypercementosis]]. Cementum thickness can increase on the root end to compensate for attritional wear of the occlusal/incisal surface and passive eruption of the tooth.<ref name="dental.pitt.edu">{{cite web|author= Max A. Listgarten|publisher= University of Pennsylvania and Temple University|url=http://www.dental.pitt.edu/informatics/periohistology/en/gu0509.htm|archiveurl=https://web.archive.org/web/20130709013900/http://www.dental.pitt.edu/informatics/periohistology/en/gu0509.htm|archivedate=9 July 2013|title=Histology of the Periodontum - Developmental Anomalies}}</ref>
+* The excessive buildup of cementum on the roots of a tooth is a pathological condition known as [[hypercementosis]]. Cementum thickness can increase on the root end to compensate for attritional wear of the occlusal/incisal surface and passive eruption of the tooth.<ref name="dental.pitt.edu">{{cite web| vauthors = Listgarten MA |publisher=University of Pennsylvania and Temple University|archive-url= https://web.archive.org/web/20130709013900/http://www.dental.pitt.edu/informatics/periohistology/en/gu0501.htm |archive-date=9 July 2013|url=http://www.dental.pitt.edu/informatics/periohistology/en/gu0501.htm|title=Histology of the Periodontium - Cementum|url-status=dead}}</ref>
 * When cementum is exposed through gingival recession, it quickly undergoes abrasion by mechanical friction because of its low mineral content and thinness. The exposure of the deeper dentin can lead to problems such as extrinsic staining and dentinal hypersensitivity.<ref name=":0"/>
 * The incidence of cemental caries increases in older adults as gingival decline occurs from either trauma or periodontal illness. It is a chronic condition that forms a large, shallow lesion and slowly invades first the root's cementum and then dentin to cause a chronic infection of the pulp. Because dental pain is a late finding, many lesions are not detected early, resulting in restorative obstacles and increased tooth loss.<ref name=":0" />
-* [[Cementicle]]s are small, spherical or ovoid [[Calcification|calcified]] masses embedded within or attached to the cementum layer on the root surface of a tooth, or lying free within the [[periodontal ligament]].<ref name="Chiego2014">{{cite book|author=Chiego Jr. DJ|title=Essentials of Oral Histology and Embryology: A Clinical Approach|url=https://books.google.com/books?id=LMrsAwAAQBAJ&pg=PA133|date=14 April 2014|publisher=Elsevier Health Sciences|isbn=978-0-323-29100-2|page=133}}</ref><ref name="Bath-Balogh2010">{{cite book|author1=Bath-Balogh M|author2=Fehrenbach MJ|title=Illustrated Dental Embryology, Histology, and Anatomy|url=https://books.google.com/books?id=uPMLBAAAQBAJ&pg=PA174|date=10 December 2010|publisher=Elsevier Health Sciences|isbn=978-1-4377-2934-4|page=174}}</ref>
+* [[Cementicle]]s are small, spherical or ovoid [[Calcification|calcified]] masses embedded within or attached to the cementum layer on the root surface of a tooth, or lying free within the [[periodontal ligament]].<ref name="Chiego2014">{{cite book|author=Chiego Jr. DJ|title=Essentials of Oral Histology and Embryology: A Clinical Approach|url=https://books.google.com/books?id=LMrsAwAAQBAJ&pg=PA133|date=14 April 2014|publisher=Elsevier Health Sciences|isbn=978-0-323-29100-2|page=133}}</ref><ref name="Bath-Balogh_2010_174">{{cite book| vauthors = Bath-Balogh M, Fehrenbach MJ|title=Illustrated Dental Embryology, Histology, and Anatomy|url=https://books.google.com/books?id=uPMLBAAAQBAJ&pg=PA174|date=10 December 2010|publisher=Elsevier Health Sciences|isbn=978-1-4377-2934-4|page=174}}</ref>
 * Cemental spurs can be found at or near the CEJ. These are symmetrical spheres of cementum attached to the cemental root surface, similar to enamel pearls. Cemental spurs result from irregular deposition of cementum on the root. They can present some clinical problems in differentiation from calculus and may be noted on radiographs; yet, because they are hard dental tissue, they are not easily removed, and thus may also interfere with periodontal treatment.<ref name=":0"/>
 ===DNA studies===
-A 2010 archeological study has found that cementum has five times the amount of [[mitochondrial DNA]] compared to [[dentine|dentin]], which is commonly sampled.<ref>{{cite journal|last=Adler|first=C.J.|author2=Haak, W.|author3=Donlon, D.|author4=Cooper, A.|title=Survival and recovery of DNA from ancient teeth and bones|journal=Journal of Archaeological Science|year=2010|volume=38|issue=5|pages=956–964|doi=10.1016/j.jas.2010.11.010}}</ref> Teeth are increasingly utilized as a source of nuclear DNA to aid identification of human remains. DNA extraction and the results of genetic analysis from the tissue are extremely variable and to some extent unpredictable. However, the quantity of DNA available in dentin is affected by age and dental disease, whereas that in cementum is not.<ref>{{cite journal|authors=Denice Higginsa, John Kaidonisa, Jeremy Austinb, Grant Townsenda, Helen Jamesa & Toby Hughes|title=Dentine and cementum as sources of nuclear DNA for use in human identification|journal=Australian Journal of Forensic Sciences|volume=43|issue=4|pages=287–295|year=2011|doi=10.1080/00450618.2011.583278}}</ref>
+A 2010 archeological study has found that cementum has five times the amount of [[mitochondrial DNA]] compared to [[dentin]], which is commonly sampled.<ref>{{cite journal | vauthors = Adler CJ, Haak W, Donlon D, Cooper A | title = Genographic Consortium. Survival and recovery of DNA from ancient teeth and bones. | journal = Journal of Archaeological Science | date = May 2011 | volume = 38 | issue = 5 | pages = 956–64 | doi = 10.1016/j.jas.2010.11.010 }}</ref> Teeth are increasingly utilized as a source of nuclear DNA to aid identification of human remains. DNA extraction and the results of genetic analysis from the tissue are extremely variable and to some extent unpredictable. However, the quantity of DNA available in dentin is affected by age and dental disease, whereas that in cementum is not.<ref>{{cite journal | vauthors = Higgins D, Kaidonis J, Townsend G, Hughes T, Austin JJ | title = Targeted sampling of cementum for recovery of nuclear DNA from human teeth and the impact of common decontamination measures | journal = Investigative Genetics | volume = 4 | issue = 1 | pages = 18 | date = October 2013 | pmid = 24139166 | doi = 10.1080/00450618.2011.583278 | pmc = 3853689 | s2cid = 85182819 }}</ref>
 == See also ==
-* [[Tooth development]]
+* [[Animal tooth development|Tooth development]]
 * [[Dentin]]
 * [[Periodontal ligament]]
@@ Line 75: / Line 77: @@
 {{Reflist|30em}}
-== External links ==
+== Further reading ==
+{{refbegin}}
-# {{cite web|author=Max A. Listgarten|publisher=University of Pennsylvania and Temple University|archiveurl=https://web.archive.org/web/20130709013900/http://www.dental.pitt.edu/informatics/periohistology/en/gu0501.htm|archivedate=9 July 2013|url=http://www.dental.pitt.edu/informatics/periohistology/en/gu0501.htm|title=Histology of the Periodontium - Cementum|url-status=dead}}
+# {{cite web| vauthors = Listgarten MA |publisher=University of Pennsylvania and Temple University|archive-url=https://web.archive.org/web/20130709013900/http://www.dental.pitt.edu/informatics/periohistology/en/gu0501.htm|archive-date=9 July 2013|url=http://www.dental.pitt.edu/informatics/periohistology/en/gu0501.htm|title=Histology of the Periodontium - Cementum|url-status=dead}}
-# Harvesting cementum from root surface: A new paradigm in the study of cementum and the cemento-dentinal junction, George Cherian, Journal of Academy of Advanced Dental Research, Vol 2; Issue 2: May 2011 at http://www.joaor.org/userfiles/Vol-2-Issue-2-May-Aug-2011/03George.pdf{{Dead link|date=July 2020 |bot=InternetArchiveBot |fix-attempted=yes }}
+# {{cite journal | vauthors = Cherian G | title = Harvesting cementum from root surface: A new paradigm in the study of cementum and the cemento-dentinal junction. | journal = Journal of Advanced Oral Research | date = May 2011 | volume = 2 | issue = 2 | pages = 17–20 | doi = 10.1177/2229411220110203 | s2cid = 5051968 }}
+{{refend}}
 {{Periodontology}}

v t e Fibrous joints of the human skull
Syndesmosis	Pterygospinous ligament Stylohyoid ligament
Sutures	Involving the frontal bone frontoethmoidal suture frontal suture coronal suture occipitomastoid lambdoid sagittal Involving the sphenoid bone sphenoethmoidal with frontal bone with parietal bone sphenosquamosal Involving the Petrous part of the temporal bone sphenopetrosal petrosquamous squamosal Facial: palatomaxillary suture Involving the zygomatic process with sphenoid bone with temporal bone with frontal bone
Mouth	Gomphosis Periodontal fiber Periodontium Dental alveolus Gingiva Cementum

v t e Anatomy of the mouth
Lip	Vermilion border Cupid's bow Frenulum of lower lip Labial commissure of mouth Philtrum White roll
Cheek	Buccal fat pad
Palate	Hard palate Soft palate Palatine raphe Incisive papilla
Gums	Interdental papilla Gingival sulcus Gingival margin Gingival fibers Junctional epithelium Mucogingival junction Sulcular epithelium Stippling Periodontium Cementum Philtrum Gingiva Periodontal ligament
Glands	Parotid gland duct Submandibular gland duct Sublingual gland duct Tubarial salivary gland
Teeth	see tooth anatomy
Tongue	Top Taste bud Median sulcus Terminal sulcus Foramen cecum Lingual tonsils Underside Frenulum Fimbriated fold Sublingual caruncle Glossoepiglottic folds Lingual septum
Back of mouth	Oropharynx fauces Plica semilunaris of the fauces Uvula Palatoglossal arch Palatopharyngeal arch Tonsillar fossa Palatine tonsil

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