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 bottom front of the dental crown near
the gums and is called a dental 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 tooth inner surfaces of the tooth
that is closer to the nerve and causes tooth sensitivity 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.