Cementoenamel junction

{{merge|Cervical margins|date=March 2026}}

{{short description|Region on a tooth's surface where cementum and enamel join}}

{{short description|Region on a tooth's surface where cementum and enamel join}}

{{Infobox anatomy

{{Infobox anatomy

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[[File:Cervical Margin.png|thumb|Cervical margin of the tooth]]

In [[dental anatomy]], the '''cementoenamel junction''' ('''CEJ)''' is the location where the [[tooth enamel|enamel]], which covers the anatomical [[Crown (tooth)|crown]] of a [[tooth]], and the [[cementum]], which covers the anatomical root of a tooth, meet. Informally it is known as the neck of the tooth.{{cite journal | vauthors = Vandana KL, Haneet RK | title = Cementoenamel junction: An insight | journal = Journal of Indian Society of Periodontology | volume = 18 | issue = 5 | pages = 549–554 | date = September 2014 | pmid = 25425813 | pmc = 4239741 | doi = 10.4103/0972-124X.142437 | doi-access = free }} The border created by these two dental tissues has much significance as it is usually the location where the [[gingiva]] (gums) attaches to a healthy tooth by fibers called the [[gingival fibers]].{{Cite book | vauthors = Clemente CD |url=http://archive.org/details/anatomyregionala00clem |title=Anatomy, a regional atlas of the human body |date=1987 |publisher=Baltimore : Urban & Schwarzenberg |others=Internet Archive |isbn=978-0-8067-0323-7}}

In [[dental anatomy]], the '''cementoenamel junction''' ('''CEJ)''' is the location where the [[tooth enamel|enamel]], which covers the anatomical [[Crown (tooth)|crown]] of a [[tooth]], and the [[cementum]], which covers the anatomical root of a tooth, meet. Informally it is known as the neck of the tooth.{{cite journal | vauthors = Vandana KL, Haneet RK | title = Cementoenamel junction: An insight | journal = Journal of Indian Society of Periodontology | volume = 18 | issue = 5 | pages = 549–554 | date = September 2014 | pmid = 25425813 | pmc = 4239741 | doi = 10.4103/0972-124X.142437 | doi-access = free }} The border created by these two dental tissues has much significance as it is usually the location where the [[gingiva]] (gums) attaches to a healthy tooth by fibers called the [[gingival fibers]].{{Cite book | vauthors = Clemente CD |url=http://archive.org/details/anatomyregionala00clem |title=Anatomy, a regional atlas of the human body |date=1987 |publisher=Baltimore : Urban & Schwarzenberg |others=Internet Archive |isbn=978-0-8067-0323-7}} It is almost synonymous with the '''cervical margin''', where the crown and root meet, and is also referred to as the tooth's neck or cervical line.{{Cite web |date=2021-01-06 |title=Parts of the tooth {{!}} Complete Anatomy |url=https://3d4medical.com/blog/parts-of-the-tooth |access-date=2025-03-30 |website=3d4medical.com |language=en-US}}

Active recession of the gingiva reveals the cementoenamel junction in the mouth and is usually a sign of an unhealthy condition. The loss of attachment is considered a more reliable indicator of [[periodontal disease]]. The CEJ is the site of major [[tooth resorption]]. A significant proportion of tooth loss is caused by tooth resorption, which occurs in 5 to 10 percent of the population. The clinical location of CEJ which is a static landmark, serves as a crucial anatomical site for the measurement of [[Periodontal probe|probing]] pocket depth (PPD) and clinical attachment level (CAL). The CEJ varies between subjects, but also between teeth from the same person.

Active recession of the gingiva reveals the cementoenamel junction in the mouth and is usually a sign of an unhealthy condition. The loss of attachment is considered a more reliable indicator of [[periodontal disease]]. The CEJ is the site of major [[tooth resorption]]. A significant proportion of tooth loss is caused by tooth resorption, which occurs in 5 to 10 percent of the population. The clinical location of CEJ which is a static landmark, serves as a crucial anatomical site for the measurement of [[Periodontal probe|probing]] pocket depth (PPD) and clinical attachment level (CAL). The CEJ varies between subjects, but also between teeth from the same person.

There exists a normal variation in the relationship of the cementum and the enamel at the cementoenamel junction. In about 60–65% of teeth, the cementum overlaps the enamel at the CEJ, while in about 30% of teeth, the cementum and enamel abut each other with no overlap. In only 5–10% of teeth, there is a space between the enamel and the cementum at which the underlying [[dentin]] is exposed.{{ cite book |vauthors=Carranza FA, Bernard GW | chapter = The Tooth-Supporting Structures |veditors=Newman MG, Takei HH, Carranza FA | title = Carranza's Clinical Periodontology | edition = 9th | location = Philadelphia | publisher = W. B. Saunders | year = 2002 | page = 43 | isbn = 978-0-7216-8331-7 }}

There exists a normal variation in the relationship of the cementum and the enamel at the cementoenamel junction. In about 60–65% of teeth, the cementum overlaps the enamel at the CEJ, while in about 30% of teeth, the cementum and enamel abut each other with no overlap. In only 5–10% of teeth, there is a space between the enamel and the cementum at which the underlying [[dentin]] is exposed.{{ cite book |vauthors=Carranza FA, Bernard GW | chapter = The Tooth-Supporting Structures |veditors=Newman MG, Takei HH, Carranza FA | title = Carranza's Clinical Periodontology | edition = 9th | location = Philadelphia | publisher = W. B. Saunders | year = 2002 | page = 43 | isbn = 978-0-7216-8331-7 }}

== Anatomy ==

The cervical margin, also known as the cervical line or neck of the tooth, represents the boundary between the enamel covering the crown and the [[cementum]] covering the root. The cementum typically overlaps the enamel, although in some cases, it may meet edge-to-edge.{{Cite journal |last1=Fichera |first1=Guido |last2=Mazzitelli |first2=Claudia |last3=Picciariello |first3=Vincenzo |last4=Maravic |first4=Tatjana |last5=Josic |first5=Uros |last6=Mazzoni |first6=Annalisa |last7=Breschi |first7=Lorenzo |date=2024 |title=Structurally compromised teeth. Part I: Clinical considerations and novel classification proposal |url=https://onlinelibrary.wiley.com/doi/10.1111/jerd.13117 |journal=Journal of Esthetic and Restorative Dentistry |language=en |volume=36 |issue=1 |pages=7–19 |doi=10.1111/jerd.13117 |pmid=37615505 |issn=1708-8240|hdl=11585/941215 |hdl-access=free }}

The cervical region includes the residual tooth structure between the [[gingival margin]] and the bone crest, encompassing the supragingival tooth area (STA) and gingival sulcus.{{Cite web |title=Everything about enamel pearls in dentistry |url=https://dentagama.com/news/enamel-pearls-in-dentistry |access-date=2025-03-30 |website=dentagama.com |language=en}}

The curvature of the CEJ varies and is influenced by the height of the contact area and the crown's buccolingual diameter. Proximal cervical curvatures are more pronounced on mesial surfaces, with central incisors exhibiting the most significant curvature, progressively decreasing toward posterior teeth . However, relationship between CEJ and cervical margin is often suggested as age related factor, as there could be extra gingiva covering the anatomical crown in a 10 - year old child, meanwhile old adults with periodontal disease can reveal their CEJ due to gingival recession. Despite this, gingival margin and CEJ are still consistently on the same or almost same location on a healthy adult.{{Cite journal |last1=Vandana |first1=Kharidi Laxman |last2=Haneet |first2=Ryana Kour |date=2014 |title=Cementoenamel junction: An insight |journal=Journal of Indian Society of Periodontology |volume=18 |issue=5 |pages=549–554 |doi=10.4103/0972-124X.142437 |doi-access=free |issn=0972-124X |pmc=4239741 |pmid=25425813}} There are three possible relationships at the CEJ: Cementum overlaps enamel (65% of cases), cementum and enamel meet end-to-end (25%), dentin is exposed due to a gap between enamel and cementum (10%) and these variations can occur around different areas of the same tooth.

=== Histology ===

Histologically, the cervical margin area can be appreciated by the [[Gums|gingiva]] histology surrounding the curvature, or [[Cementoenamel junction|cemento-enamel junction]] that aligns on the same location on a healthy tooth individual. However, due to pathological reasons such as [[gingival recession]] or [[Periodontal disease|periodontitis]], the gingival margin may get located below CEJ, hence histologically it is difficult to have a precise sample to study on.

== Formation ==

== Formation ==

=== External ===

=== External ===

External resorption can be classified into four categories by its clinical and histologic manifestations: external surface resorption, external [[inflammation|inflammatory]] root resorption, replacement resorption, and [[Tooth ankylosis|ankylosis]]. External inflammatory root resorption can be further categorized into cervical resorption with or without a vital [[Pulp (tooth)|pulp]] (invasive cervical root resorption) and external apical root resorption.

External resorption can be classified into four categories by its clinical and histologic manifestations: external surface resorption, external [[inflammation|inflammatory]] root resorption, replacement resorption, and [[Tooth ankylosis|ankylosis]]. External inflammatory root resorption can be further categorized into cervical resorption with or without a vital [[Pulp (tooth)|pulp]] (invasive cervical root resorption) and external apical root resorption.

== Periodontal consideration ==

=== Biological width ===

The biological width is a crucial factor in maintaining periodontal health. It refers to the soft tissue dimensions coronal to the alveolar bone, consisting of [[junctional epithelium]] and supracrestal connective tissue attachment. However, by violating the biological width during restorative procedures can lead to periodontal breakdown, inflammation, gingival recession, and bone loss. Gargiulo et al. (1961) established that the biological width is approximately 2.04 mm, composed of epithelial and connective tissue components.{{Cite journal |last1=Felemban |first1=Mohammed Fareed |last2=Khattak |first2=Osama |last3=Alsharari |first3=Thani |last4=Alzahrani |first4=Abdulrahman H. |last5=Ganji |first5=Kiran Kumar |last6=Iqbal |first6=Azhar |date=2023-11-03 |title=Relationship between Deep Marginal Elevation and Periodontal Parameters: A Systematic Review |journal=Medicina (Kaunas, Lithuania) |volume=59 |issue=11 |page=1948 |doi=10.3390/medicina59111948 |doi-access=free |issn=1648-9144 |pmc=10673413 |pmid=38003997}}

=== Importance ===

Subgingival crown margins can contribute to gingivitis and periodontitis, leading to attachment loss,{{cn|date=April 2025}} and improperly placed restoration margins and ill-fitting restorations violate the biological width, impacting periodontal health. Key considerations for subgingival margins include: proper contouring in the gingival third, polishing and rounding of the margin, ensuring an adequate zone of attached gingiva, avoiding biological width violation, regular maintenance and patient compliance to prevent periodontal issues.{{Cite journal |last1=Nugala |first1=Babitha |last2=Kumar |first2=Bb Santosh |last3=Sahitya |first3=S. |last4=Krishna |first4=P. Mohana |date=2012 |title=Biologic width and its importance in periodontal and restorative dentistry |journal=Journal of Conservative Dentistry |volume=15 |issue=1 |pages=12–17 |doi=10.4103/0972-0707.92599 |doi-access=free |issn=0974-5203 |pmc=3284004 |pmid=22368328}}

== Diseases of cervical margin area ==

Due to the cervical margin area being extremely close to the cervical part of tooth, the diseases related are usually overlapping with other diseases that could happen in the area.

=== Carious lesions ===

[[Tooth decay|Caries]] occurring at the cervical region of the tooth are often linked to carious cervical lesions (CCLs), which are commonly found in patients with poor oral hygiene or exposed root surfaces due to improper brushing technique.

=== [[Non-carious cervical lesions|Non Cervical carious lesions (NCCL)]] ===

[[File:Dental abrasion klinovidny de207.jpg|thumb|NCCL, a type of lesion seen in dental diseases due to parafunctional habits]]

* '''Abfraction:''' Caused by occlusal forces leading to microfractures in the enamel and dentin

* '''Abrasion:''' Mechanical wear due to habits like aggressive tooth brushing

* '''Erosion:''' Chemical dissolution from acidic foods, beverages, or gastric reflux{{Cite journal |last=Rappeport |first=Stephen A |date=November 2018 |title=Non Carious Cervical Lesions and the Abfractive process |url=https://www.drtomcoleman.com/storage/app/media/decsions-in-dentistry-november-2018-pdf-of-article.pdf |journal=Decisions in Dentistry}}

=== Common treatments ===

==== Non-Carious Cervical Lesion (NCCL) Management ====

Composite restorations commonly restore lost tooth structure, and [[Glass ionomer cement|Glass Ionomer Cement]] commonly used too due to difficulty in moisture control

==== Deep Margin Elevation (DME) ====

As proposed by Diestschi and Spreafico, this technique involves coronally repositioning sub-gingival margins using composite resin. It aids in dental dam isolation, impression-taking, restoration placement, and finishing. It is a conservative alternative to [[crown lengthening]], which requires the removal of bone and gingival tissue. Moreover, DME improves bonding strength and marginal integrity, especially in cases where indirect restorations are planned.{{Cite journal |last1=Geo |first1=T. D. |last2=Gupta |first2=Saurabh |last3=Gupta |first3=Shilpi Gilra |last4=Rana |first4=Kuldeep singh |date=2024-01-01 |title=Is Deep margin elevation a reliable tool for cervical margin relocation? – A comparative review |journal=Journal of Oral Biology and Craniofacial Research |volume=14 |issue=1 |pages=33–38 |doi=10.1016/j.jobcr.2023.12.002 |pmid=38481655 |issn=2212-4268|pmc=10935500 }} The Immediate Dentin Sealing (IDS) technique, often performed alongside DME, enhances bond strength, reduces marginal leakage, and minimizes post-operative sensitivity {{Cite journal |last1=Aldakheel |first1=Majed |last2=Aldosary |first2=Khalid |last3=Alnafissah |first3=Shatha |last4=Alaamer |first4=Rahaf |last5=Alqahtani |first5=Anwar |last6=Almuhtab |first6=Nora |date=2022-10-18 |title=Deep Margin Elevation: Current Concepts and Clinical Considerations: A Review |journal=Medicina (Kaunas, Lithuania) |volume=58 |issue=10 |page=1482 |doi=10.3390/medicina58101482 |doi-access=free |issn=1648-9144 |pmc=9610387 |pmid=36295642}}

== Clinical relevance ==

=== Endodontics ===

In endodontics, gaining access to the pulp chamber is an essential step to complete procedures such as [[Root canal treatment|Root Canal Treatment]] or [[Pulpotomy]]. According to the Law of Centrality in Endodontics, the pulp chamber of the tooth is located at the level of the cementoenamel junction.{{Cite journal |date=2010 |title=Colleagues for Excellence Access Opening and Canal Location |url=https://www.aae.org/specialty/wp-content/uploads/sites/2/2010/04/ECFESpring2010_Final-2.pdf |journal=Colleagues for Excellence Access Opening and Canal Location.}}

The cervical margin area is extremely critical in determining the success of few restorations in dentistry, such as [[Crown (dental restoration)|crowns]] and [[Bridge (dentistry)|bridges]]. A ''good preparation'' around the cervical margin area, or the tooth structure near the cervical margin ensures the preparation is able to provide marginal integrity for accurate fit of the crown, reduced overhang between crown and cement to prevent bacteria or plaque accumulation.{{Cite book |last=Wiskott |first=H. W. Anselm |title=Fixed prosthodontics: principles and clinics |date=2011 |publisher=Quintessence Publishing |isbn=978-1-85097-208-2 |location=London Berlin Chicago}} and providing resistance to occlusal forces to prevent fracture of the restorative material.{{Cite journal |last1=Hegde |first1=Shipha |last2=Deb |first2=Anamika |last3=Almudarris |first3=Ban A. |last4=Chitumalla |first4=Rajkiran |last5=Jaiswal |first5=Shashank |last6=R |first6=Satheesh |last7=Nadiger |first7=Ramesh K. |last8=Anehosur |first8=Gouri V. |last9=Hegde |first9=Shipha |last10=Deb |first10=Anamika |last11=Iii |first11=Ban A. Almudarris |last12=Chitumalla |first12=Rajkiran |last13=Jaiswal |first13=Shashank |last14=R |first14=Satheesh |last15=Nadiger |first15=Ramesh K. |date=2024-03-05 |title=Stress Distribution on Prepared Tooth With Shoulder and Radial Shoulder Margin to Receive Crowns of Three Different Materials: A Finite Element Analysis |journal=Cureus |language=en |volume=16 |issue=3 |article-number=e55538 |doi=10.7759/cureus.55538 |doi-access=free |issn=2168-8184 |pmc=10993099 |pmid=38576681}}

== References ==

== References ==