Abfraction

Abfraction is a theoretical concept explaining a loss of tooth structure not caused by tooth decay (non-carious cervical lesions). 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 (CEJ), undergoes large amounts of stress, causing micro fractures and tooth tissue loss.

Abfraction is a form of non-carious tooth tissue loss that occurs along the gingival margin. 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, and erosion.

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 and enamel of the tooth. These lesions generally occur around the cervical areas of the dentition.

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.

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