Abfraction

[sushantpatel_doc]

Abfraction is the loss of tooth structure from flexural forces. It is hypothesized that enamel, especially at the cementoenamel junction (CEJ), undergo this pattern of destruction by separating the enamel rods.
As teeth flex under pressure, the arrangement of teeth touching each other, known as occlusion, causes tension on one side of the tooth and compression on the other side of the tooth. This is believed to cause V-shaped depressions on the side under tension and C-shaped depressions on the side under compression.

Dealing with hypersensitivity of teeth with non-carious cervical lesions is a difficult task. These were thought to be erosion- abrasion lesions. It was Grippo, who originated the term ‘abfraction’, in 1991 to describe the pathologic loss of tooth enamel and dentin caused by biomechanical loading of forces.

Up until now, research into the causes of abfractions seems to be divided into two camps- those who argue for tooth brushes and other artificial forces as the cause and those researchers who point to internal physiological sources as the culprit. The latter argument, though not providing a complete explanation, does offer a significant clue to the real cause of this troubling phenomenon.

The earliest review in English, of the erosion –abrasion issue as it relates to tooth brushing and dentifrices seem to be the original works of WD Miller in the late 1880s and early 1900s. He believed that erosion was caused by weak acids or gritty tooth powders, or by both, assisted by the toothbrush.

In 1950, SC Miller suggested that traumatic and lateral forces by the tongue, lips and cheeks were contributors to gingival recession. Glickman, in 1965 proposed that susceptibility to recession was influenced by many factors such as the position of teeth in the arch, the angle of the root in the bone, and the mesio-distal curvature of the tooth surfaces.

Yettram et al found that abfraction could occur even gingival to the margin of crowns and that the amount of load placed on the teeth was the key factor. Finally, in 1984, Lee and Eakle described lateral forces as the cause of the tooth structure breakdown. Grippo had stated that the forces could be static, such as those produced by swallowing and clenching, or cyclic, as in those generated during chewing action.

The abfractive lesions are caused by flexure and ultimate material fatigue of susceptible teeth at locations away from the point of loading. The breakdown is dependent on the magnitude, duration, frequency and location of the forces.

        

[sushantpatel_doc]

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[Anonymous]

A person exerting lateral forces on the tooth because
of a tongue thrust (blue arrow) should be retrained to
swallow properly by a person specially trained in
myofunctional therapy or orofacial myology.
Treatment Goals continued:
A person who is a bruxer / clencher can
best be helped by an occlusal splint
A person exerting lateral forces on the tooth because
of a tongue thrust (blue arrow) should be retrained to
swallow properly by a person specially trained in
myofunctional therapy or orofacial myology.
treatment of abfraction:

1. Minimal involvement, with a small amount of tooth structure gone from the neck of the tooth and a small amount of tooth sensitivity (usually to cold)

– no treatment is acceptable

– occlusal equilibration (bite adjustment)

-dental varnishes, topical fluoride, Sensodyne tooth paste

– protective acrylic guard

2. Moderate involvement, which is more likely to be sensitive to cold, and also has more soft tissue recession and visible loss of tooth structure

– occlusal equilibration (bite adjustment)

-dental varnishes, topical fluoride, Sensodyne tooth paste

– protective acrylic guard

– bonding material placement to cover root surface

3. Advanced involvement often has root sensitivity that is severe and irreversible

– occlusal equilibration (bite adjustment)

– protective acrylic guard

– bonding material placement to cover root surface

– crowning tooth for more advanced coverage

– root canal treatment depending on the severity

II. Filling material for abfraction: Depending on the severity of the case and doctor preference, several types of materials can be used:

1. Composite resins
2. Flowable composite resins
3. Glass ionomers

We focus our efforts in the direction of management of forces, as we believe this is the most dominant factor in this multifactorial problem. The excessive forces that cause abfractions can lead to several common problems:

1)Abfractions
2) Sensitive teeth
3) Loosening of teeth
4) Excessive wear of teeth
5) Change in alignment of teeth
6) Bone breakdown and bone loss
7) Broken or destroyed restorations
8) Non-bacterial, non-plaque related gingival recession
9) Opening of contacts

        

[Author]

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