When you bend a stick too much, the stick breaks. When you grind on a tooth too much, the tooth flexes and the area that bends compresses the crystals of tooth structure which dislodge and dissolves leaving a notch on the root. The notch is at the neck of the tooth near the gum, this defect is called abfraction. Years ago dentists and hygienists believed that it was from brushing too hard but many patients who do not brush have these notches. Dentists now know that the notches are not due to hard bristle brushes or hard brushing.
The most common teeth to suffer with dental abfractions are the bicuspid teeth, especially the upper bicuspids but the notches can also be found on cuspids and molars. The notch is created because the minerals that form the dental root crack off and dissolve due to the grinding pressures. This exposes the inner surfaces of the tooth that lie closer to the nerve and causes tooth to be sensitive to hot and cold. Desensitizing toothpastes like Denquel or Sensodyne help reduce the sensitivity, but the real cause is tooth grinding.
Some dentists attempt to fill the abfraction with white dental fillings called composites but because the tooth still flexes and bends, these white filling often pop out leaving a bigger hole than the original notch. We recommend that patients first get a protective guard before attempting to fill their notches.
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.
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.