![Abfraction](https://upload.wikimedia.org/wikipedia/commons/b/bc/Abfraction.jpg)
Abfraction is a theoretical concept explaining a loss of tooth structure not caused by
tooth decay
Tooth decay, also known as cavities or caries, is the breakdown of teeth due to acids produced by bacteria. The cavities may be a number of different colors from yellow to black. Symptoms may include pain and difficulty with eating. Complicatio ...
(
non-carious cervical lesions
Non-carious cervical lesions (NCCLs) are a group of lesions that are characterised by a loss of hard dental tissue at the cementoenamel junction (CEJ) region at the neck of the tooth, without the action of microorganisms or inflammatory processe ...
). It is suggested that these lesions are caused by forces placed on the teeth during biting, eating, chewing and grinding; the
enamel, especially at the
cementoenamel junction
The cementoenamel junction, frequently abbreviated as the CEJ, is a slightly visible anatomical border identified on a tooth. It is the location where the enamel, which covers the anatomical crown of a tooth, and the cementum, which covers the ...
(CEJ), undergoes large amounts of stress, causing micro fractures and tooth tissue loss. Abfraction appears to be a modern condition, with examples of non-carious cervical lesions in the archaeological record typically caused by other factors.
Definition
![Dental abrasion klinovidny de207](https://upload.wikimedia.org/wikipedia/commons/4/42/Dental_abrasion_klinovidny_de207.jpg)
Abfraction is a form of non-carious tooth tissue loss that occurs along the
gingival margin
The free gingival margin is the interface between the sulcular epithelium and the epithelium of the oral cavity. This interface exists at the most coronal point of the gingiva, otherwise known as the crest of the marginal gingiva.
Because the sh ...
.
In other words, abfraction is a mechanical loss of tooth structure that is not caused by tooth decay, located along the gum line. There is theoretical evidence to support the concept of abfraction, but little experimental evidence exists.
The term abfraction was first published in 1991 in a journal article dedicated to distinguishing the lesion. The article was titled "Abfractions: A New Classification of Hard Tissue Lesions of Teeth" by John O. Grippo.
This article introduced the definition of abfraction as a "pathologic loss of hard tissue tooth substance caused by bio mechanical loading forces". This article was the first to establish abfraction as a new form of lesion, differing from
abrasion,
attrition
Attrition may refer to
*Attrition warfare, the military strategy of wearing down the enemy by continual losses in personnel and material
**War of Attrition, fought between Egypt and Israel from 1968 to 1970
**War of attrition (game), a model of agg ...
, and
erosion
Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...
.
Tooth tissue is gradually weakened causing tissue loss through fracture and chipping or successively worn away leaving a non-carious lesion on the tooth surface. These lesions occur in both the
dentine
Dentin () (American English) or dentine ( or ) (British English) ( la, substantia eburnea) is a calcified tissue of the body and, along with enamel, cementum, and pulp, is one of the four major components of teeth. It is usually covered by ena ...
and
enamel of the tooth. These lesions generally occur around the cervical areas of the dentition.
Signs and symptoms
![Abfraction lesion final](https://upload.wikimedia.org/wikipedia/commons/f/f6/Abfraction_lesion_final.jpg)
Abfraction lesions will generally occur in the region on the tooth where the greatest tensile stress is located. In statements such as these there is no comment on whether the lesions occur above or below the CEJ. One theory suggests that the abfraction lesions will only form above the CEJ.
However, it is assumed that the abfraction lesions will occur anywhere in the cervical areas of affected teeth. It is important to note that studies supporting this configuration of abfraction lesions also state that when there is more than one abnormally large tensile stress on a tooth two or more abfraction lesions can result on the one surface.
When looking at abfraction lesions there are generally three shapes in which they appear, appearing as either wedge, saucer or mixed patterns.
Wedge and saucer shaped lesions are the most common, whereas mixed lesions are less frequently identified in the oral cavity.
In reference to figure 1, wedge shaped lesions have the sharpest internal line angles and saucer/mixed shaped lesions are either smooth internally, or a variety.
Clinically, people with abfraction lesions can also present with tooth sensitivity in the associated areas. This occurs because as the abfraction lesions appear, dentine/cementum is exposed.
The dentine and cementum are less dense than tooth enamel and therefore more susceptible to sensation from thermal/mechanical sources.
Causes
As abfraction is still a controversial theory there are various ideas on what causes the lesions. Because of this controversy the true causes of abfraction also remain disputable.
[Antonelli JR, Hottel TL, Garcia-Godoy F. Abfraction Lesions – Where do They Come From? A Review of the Literature. J Tenn Dent Assoc. 2013; 93(1):14-19] Researchers have proposed that abfraction is caused by forces on the tooth from the teeth touching together, occlusal forces, when chewing and swallowing.
These lead to a concentration of stress and flexion at the area where the enamel and cementum meet (CEJ).
This theoretical stress concentration
and flexion over time causes the bonds in the enamel of the tooth to break down and either fracture or be worn away from other stressors such as erosion or abrasion.
The people who initially proposed the theory of abfraction believe the occlusal forces alone cause the lesions
without requiring the added abrasive components such as toothbrush and paste or erosion.
If teeth come together in a non-ideal bite the researchers state that this would create further stress in areas on the teeth.
Teeth that come together too soon or come under more load than they are designed for could lead to abfraction lesions.
The impacts of restorations on the chewing surfaces of the teeth being the incorrect height has also been raised as another factor adding to the stress at the CEJ.
Further research has shown that the normal occlusal forces from chewing and swallowing are not sufficient to cause the stress and flexion required to cause abfraction lesions.
However, these studies have shown that the forces are sufficient in a person who grinds their teeth (
bruxism
Bruxism is excessive teeth grinding or jaw clenching. It is an oral parafunctional activity; i.e., it is unrelated to normal function such as eating or talking. Bruxism is a common behavior; reports of prevalence range from 8% to 31% in the gene ...
).
Several studies have suggested that it is more common among those who grind their teeth,
as the forces are greater and of longer duration. Yet further studies have shown that these lesions do not always appear in people with bruxism and others without bruxism have these lesions.
There are other researchers who would state that occlusal forces have nothing to do with the lesions along the CEJ and that it is the result of abrasion from toothbrush with toothpaste that causes these lesions.
Being theoretical in nature there is more than one idea on how abfraction presents clinically in the mouth. One theory of its clinical features suggests that the lesions only form above the
cementoenamel junction
The cementoenamel junction, frequently abbreviated as the CEJ, is a slightly visible anatomical border identified on a tooth. It is the location where the enamel, which covers the anatomical crown of a tooth, and the cementum, which covers the ...
(CEJ) (which is where the enamel and cementum meet on a tooth).
If this is kept in mind, it serves as a platform for it to be distinguished from other non-carious lesions, such as tooth-brush abrasion.
Treatment
Treatment of abfraction lesions can be difficult due to the many possible causes. To provide the best treatment option the dental clinician must determine the level of activity and predict possible progression of the lesion.
A No.12 scalpel is carefully used by the dental clinician to make a small indentation on the lesion, this is then closely monitored for changes. Loss of a scratch mark signifies that the lesion is active and progressing.
It is usually recommended when an abfraction lesion is less than 1 millimeter, monitoring at regular intervals is a sufficient treatment option. If there are concerns around aesthetics or clinical consequences such as
dentinal hypersensitivity, a
dental restoration
Dental restoration, dental fillings, or simply fillings are treatments used to restore the function, integrity, and morphology of missing tooth structure resulting from caries or external trauma as well as to the replacement of such structure sup ...
(white filling) may be a suitable treatment option.
Aside from restoring the lesion, it is equally important to remove any other possible causative factors.
Adjustments to the biting surfaces of the teeth alter the way the upper and lower teeth come together, this may assist by redirecting the occlusal load.
The aim of this is to redirect the force of the load to the long axis of the tooth, therefore removing the stress on the lesion. This can also be achieved by altering the tooth surfaces such as cuspal inclines, reducing heavy contacts and removing premature contacts.
If
bruxism
Bruxism is excessive teeth grinding or jaw clenching. It is an oral parafunctional activity; i.e., it is unrelated to normal function such as eating or talking. Bruxism is a common behavior; reports of prevalence range from 8% to 31% in the gene ...
is deemed a contributing factor an occlusal splint can be an effective treatment for eliminating the irregular forces placed on the tooth.
Controversy
Abfraction has been a controversial subject since its creation in 1991.
This is due to the clinical presentation of the tooth loss, which often presents in a manner similar to that of
abrasion or
erosion
Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...
. The major reasoning behind the controversy is the similarity of abfraction to other non carious lesions and the prevalence of multiple theories to potentially explain the lesion. One of the most prevalent theories is called "the theory of non-carious cervical lesions" which suggests that tooth flexion, occurring due to
occlusion
Occlusion may refer to:
Health and fitness
* Occlusion (dentistry), the manner in which the upper and lower teeth come together when the mouth is closed
* Occlusion miliaria, a skin condition
* Occlusive dressing, an air- and water-tight trauma ...
factors, impacts on the vulnerable area near the
cementoenamel junction
The cementoenamel junction, frequently abbreviated as the CEJ, is a slightly visible anatomical border identified on a tooth. It is the location where the enamel, which covers the anatomical crown of a tooth, and the cementum, which covers the ...
.
This theory is not widely accepted among the professional community as it suggests that the only factor is
occlusion
Occlusion may refer to:
Health and fitness
* Occlusion (dentistry), the manner in which the upper and lower teeth come together when the mouth is closed
* Occlusion miliaria, a skin condition
* Occlusive dressing, an air- and water-tight trauma ...
. Many researchers argue that this is inaccurate as they contend that the abfraction lesion is a multifactorial (has many causative factors) lesion with other factors such as
abrasion or
erosion
Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...
.
This controversy around the causative factors, along with the recency of the lesion classification, are some of the reasons why many dental clinicians are looking at the lesion with some scepticism. More research is needed to fully clear up the controversy surrounding the abfraction lesion.
See also
*
Tooth wear
Tooth wear refers to loss of tooth substance by means other than dental caries. Tooth wear is a very common condition that occurs in approximately 97% of the population. This is a normal physiological process occurring throughout life; but with in ...
*
Abrasion
*
Attrition
Attrition may refer to
*Attrition warfare, the military strategy of wearing down the enemy by continual losses in personnel and material
**War of Attrition, fought between Egypt and Israel from 1968 to 1970
**War of attrition (game), a model of agg ...
*
Bruxism
Bruxism is excessive teeth grinding or jaw clenching. It is an oral parafunctional activity; i.e., it is unrelated to normal function such as eating or talking. Bruxism is a common behavior; reports of prevalence range from 8% to 31% in the gene ...
*
Erosion
Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...
References
* Summit, James B., J. William Robbins, and Richard S. Schwartz. ''Fundamentals of Operative Dentistry: A Contemporary Approach''. 2nd edition. Carol Stream, Illinois, Quintessence Publishing Co, Inc, 2001. .
*
{{oral pathology
Acquired tooth pathology