Abfraction of Tooth

Abfraction lesion put in simple terms are notches or small cracks on the teeth caused due to natural flexing of the tooth caused by excessive forces. As the occlusal surface of the tooth is covered by Enamel and the bottom forces of the tooth is supported by Bone, on excessive forces the pressure is concentrated on the cervical or the tooth near the gum line leading to loss of tooth structure or cracks or notches formed as a result.

Abfraction is different from Abrasion mainly based on the causes, Abrasion is caused due to mechanical trauma like excessive tooth brushing etc and in Abfraction the cause is due to excessive occlusal forces.

Definition of Abfraction:

Abfractions is the pathological loss of tooth enamel and dentin caused by bio mechanical loading forces on the affected teeth.

What are the forces causing Abfraction:

There are two types of forces which will lead to Abfraction, these forces cause repeated flexure and ultimate material fatigue to the affected tooth at locations away from the point of loading.

• Static forces: Produced during swallowing, tongue thrusting and clenching
• Cyclic forces: Forces produced during chewing

Image Source: http://pictures.doccheck.com/com/photo/1527-abfraction

Clinical features of Abfraction:

Abfraction is clinically seen as the loss of tooth structure in the cervical region due to no carious reasons or due to excessive forces like Static forces and Cyclic forces.

• First signs of Abfraction is sensitivity felt on drinking or eating cold stuff
• Loss of Enamel and some part of dentin on the buccal aspect of the tooth mainly on the gum line and not seen on the occlusal surface.
• Abfraction is seen mainly in people with open bit or very deep class I cavity which make the tooth more prone to abfraction
• Due to excessive lateral forces there will be failure of restorations on the cervical region which leads to abfraction in some people
• As an effect of Abfraction, stress lines on the tooth surface and sometimes fracture of the tooth may be seen

Treatment for Abfraction of teeth:

As Abfraction is the loss of enamel, the best treatment plan is to replace the missing tooth structure with restorative materials like Glass Ionomer cement or Composite material depending on the location and the amount of lesion.

References:

• Essentials of Oral Pathology – Purkait
• Oral Pathology: Shafers