Tertiary dentin: Difference between revisions

Latest revision as of 19:21, 22 March 2025

Type of dentin formed in response to stimuli

Tertiary dentin is a type of dentin that forms in response to external stimuli, such as dental caries, tooth wear, or dental trauma. It is part of the tooth's natural defense mechanism to protect the dental pulp from potential damage.

Formation[edit]

Tertiary dentin is produced by odontoblasts, which are specialized cells located in the dental pulp. When the tooth is exposed to stimuli that threaten its integrity, odontoblasts are stimulated to produce tertiary dentin. This process can be triggered by various factors, including:

Caries: The presence of dental caries can stimulate the formation of tertiary dentin as the tooth attempts to protect the pulp from bacterial invasion.
Attrition, abrasion, and erosion: These forms of tooth wear can lead to the exposure of dentin, prompting the formation of tertiary dentin.
Dental trauma: Physical injury to the tooth can also result in the production of tertiary dentin as a reparative response.

Types[edit]

Tertiary dentin can be classified into two main types based on the nature of the stimulus and the response of the odontoblasts:

Reactionary dentin: This type of tertiary dentin is formed by pre-existing odontoblasts in response to mild stimuli. The odontoblasts increase their activity to produce additional dentin, which is usually similar in structure to primary and secondary dentin.

Reparative dentin: When the stimulus is more severe, such as in the case of deep caries or significant trauma, the original odontoblasts may die. In such cases, new odontoblast-like cells differentiate from the pulp and produce reparative dentin. This type of dentin often has a more irregular structure compared to reactionary dentin.

Structure[edit]

The structure of tertiary dentin can vary significantly depending on the type and severity of the stimulus. Reactionary dentin tends to have a more regular tubular structure, similar to that of primary and secondary dentin. In contrast, reparative dentin often has a more irregular, atubular structure, which can make it less permeable and more resistant to further damage.

Function[edit]

The primary function of tertiary dentin is to protect the dental pulp from external threats. By forming a barrier, tertiary dentin helps to seal off the pulp from bacterial invasion and other harmful stimuli. This protective mechanism is crucial for maintaining the vitality of the tooth and preventing further damage.

Clinical Significance[edit]

Understanding the formation and characteristics of tertiary dentin is important in dentistry, particularly in the diagnosis and treatment of dental caries and other forms of tooth damage. The presence of tertiary dentin can indicate a history of tooth stress or damage and may influence treatment decisions.

Related pages[edit]

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-'''Tertiary dentin''' (including reparative dentin or sclerotic dentin) forms as a reaction to stimulation, including [[Tooth decay|caries]], [[Tooth wear|wear]] and [[Enamel fracture|fractures]].<ref name=":0">{{cite journal |last1=Towle |first1=Ian |title=Tertiary Dentine Frequencies in Extant Great Apes and Fossil Hominins |journal=Open Quaternary |date=20 March 2019 |volume=5 |issue=1 |pages=2 |doi=10.5334/oq.48 }}</ref> Tertiary dentin is therefore a mechanism for a tooth to ‘heal’, with new material formation protecting the [[Pulp (tooth)|pulp chamber]] and ultimately therefore protects the tooth and individual against abscesses and infection. This form of dentine can be easily distinguished on the surface of a tooth, and is much darker in appearance compared to primary dentine.<ref>{{cite book |doi=10.1017/cbo9780511614477 |title=Teeth |year=2005 |last1=Hillson |first1=Simon |isbn=978-0-511-61447-7 }}{{pn|date=May 2019}}</ref> Tertiary dentine will often not be visible on the surface of a tooth, but because it is more dense it can be viewed on a [[Micro-CT|Micro-CT scan]] of the tooth.<ref>{{cite journal |last1=Moggi-Cecchi |first1=Jacopo |last2=Menter |first2=Colin |last3=Dori |first3=Irene |last4=Irish |first4=Joel D. |last5=Riga |first5=Alessandro |last6=Towle |first6=Ian |title=Root caries on a Paranthropus robustus third molar from Drimolen |journal=bioRxiv |date=12 March 2019 |pages=573964 |doi=10.1101/573964 }}</ref>
+{{Short description|Type of dentin formed in response to stimuli}}
-[[File:Tertiary dentin.jpg|thumb|Tertiary dentin on the surface of a gorilla tooth. The darker area indicated by the white arrow is tertiary dentin and has formed as a response to tooth wear.]]
-Wear on the surface of a tooth can lead to the exposure of the underlying dentine. When wear is severe tertiary dentine may form to help protect the pulp chamber.<ref>{{cite journal |last1=Zuo |first1=Jing |last2=Zhen |first2=Jiaxiu |last3=Wang |first3=Fei |last4=Li |first4=Yueheng |last5=Zhou |first5=Zhi |title=Effect of Low-Intensity Pulsed Ultrasound on the Expression of Calcium Ion Transport-Related Proteins during Tertiary Dentin Formation |journal=Ultrasound in Medicine & Biology |date=January 2018 |volume=44 |issue=1 |pages=223–233 |doi=10.1016/j.ultrasmedbio.2017.09.006 |pmid=29079395 }}</ref> Frequency of tertiary dentin in different species of primate suggests teeth 'heal' at different rates in different species.<ref name=":2">{{cite journal |last1=Towle |first1=Ian |title=Tertiary Dentine Frequencies in Extant Great Apes and Fossil Hominins |journal=Open Quaternary |date=20 March 2019 |volume=5 |issue=1 |pages=2 |doi=10.5334/oq.48 }}</ref> Gorillas have a high rate of tertiary dentin formation, with over 90% of worn teeth showing tertiary dentine.<ref name=":2" /> [[Hominini|Hominins]] have a much lower rate of tertiary dentin formation, with around 15% of teeth that have dentin exposed through wear showing tertiary dentin formation.<ref name=":2" /> Chimpanzees have rates in between gorillas and humans, with 47% of worn teeth showing ‘healing’.
+'''Tertiary dentin''' is a type of [[dentin]] that forms in response to external stimuli, such as [[dental caries]], [[tooth wear]], or [[dental trauma]]. It is part of the tooth's natural defense mechanism to protect the [[pulp (tooth)|dental pulp]] from potential damage.
-Clinical studies have researched the properties of tertiary dentine formation, including anatomy in both humans and animal models, usually from an oral health perspective.<ref name=":3">{{cite journal |last1=Neves |first1=V.C.M. |last2=Sharpe |first2=P.T. |title=Regulation of Reactionary Dentine Formation |journal=Journal of Dental Research |date=29 November 2017 |volume=97 |issue=4 |pages=416–422 |doi=10.1177/0022034517743431 |pmid=29185832 }}</ref> Genetic changes in animal models can increase tertiary dentine production.<ref name=":3" /> This suggests certain species may have evolved to produce tertiary dentin in response to dietary changes. For example, gorillas may have evolved high rates of tertiary dentin as protection against severe wear, since they consume a lot of tough vegetation.<ref name=":0" />
+==Formation==
+Tertiary dentin is produced by [[odontoblast]]s, which are specialized cells located in the [[dental pulp]]. When the tooth is exposed to stimuli that threaten its integrity, odontoblasts are stimulated to produce tertiary dentin. This process can be triggered by various factors, including:
-== References ==
+* [[Caries]]: The presence of dental caries can stimulate the formation of tertiary dentin as the tooth attempts to protect the pulp from bacterial invasion.
-{{Reflist}}
+* [[Attrition (dental)|Attrition]], [[abrasion (dental)|abrasion]], and [[erosion (dental)|erosion]]: These forms of tooth wear can lead to the exposure of dentin, prompting the formation of tertiary dentin.
+* [[Dental trauma]]: Physical injury to the tooth can also result in the production of tertiary dentin as a reparative response.
-[[Category:Dentistry| ]]
+==Types==
-{{dictionary-stub1}}
+Tertiary dentin can be classified into two main types based on the nature of the stimulus and the response of the odontoblasts:
+* '''Reactionary dentin''': This type of tertiary dentin is formed by pre-existing odontoblasts in response to mild stimuli. The odontoblasts increase their activity to produce additional dentin, which is usually similar in structure to primary and secondary dentin.
+* '''Reparative dentin''': When the stimulus is more severe, such as in the case of deep caries or significant trauma, the original odontoblasts may die. In such cases, new odontoblast-like cells differentiate from the pulp and produce reparative dentin. This type of dentin often has a more irregular structure compared to reactionary dentin.
+==Structure==
+The structure of tertiary dentin can vary significantly depending on the type and severity of the stimulus. Reactionary dentin tends to have a more regular tubular structure, similar to that of primary and secondary dentin. In contrast, reparative dentin often has a more irregular, atubular structure, which can make it less permeable and more resistant to further damage.
+==Function==
+The primary function of tertiary dentin is to protect the dental pulp from external threats. By forming a barrier, tertiary dentin helps to seal off the pulp from bacterial invasion and other harmful stimuli. This protective mechanism is crucial for maintaining the vitality of the tooth and preventing further damage.
+==Clinical Significance==
+Understanding the formation and characteristics of tertiary dentin is important in [[dentistry]], particularly in the diagnosis and treatment of dental caries and other forms of tooth damage. The presence of tertiary dentin can indicate a history of tooth stress or damage and may influence treatment decisions.
+==Related pages==
+* [[Dentin]]
+* [[Odontoblast]]
+* [[Dental pulp]]
+* [[Dental caries]]
+* [[Tooth wear]]
+* [[Dental trauma]]
+[[Category:Dentistry]]
+[[Category:Tooth anatomy]]