biting foreign objects such as a pipestem, thread, or
bobby pins. Other mechanical actions such as a poorly
fitted clasp of partial dentures or acid from food debris
can cause abrasion.
Erosion is a loss of tooth substances from a
chemical process that does not involve bacteria. It
occurs usually on the facial surfaces at the gingival
third of the crown and often involves the maxillary
incisors. The enamel and dentin on the floor of the
lesion are smooth, hard, and glistening. Some types of
lesions are called idiopathic erosion because the
factors producing this condition are unknown or may
occur from a known acid source such as people who
have bulimia (who vomit frequently).