Tooth enamel is over 90% mineral, which dissolves in acid. Any acid can dissolve tooth enamel, including those found in food and drink. Among the common dietary acids are citric acid (found at especially destructive pH in lemons), phosphoric acid (a common ingredient in soft drinks) and ascetic acid (found in vinegar).
The teeth in Figure 1 exhibit (acid) chemical erosion secondary to the eating disorder, bulimia. The lingual surfaces (facing the inside of the mouth) are commonly more eroded than the facial surfaces (shown) in bulimic patients. Acid eroded teeth are easy to spot. The enamel appears uniformly thin and transparent, even on areas that do not wear against an opposing tooth, and once-sharp edges are uniformly rounded. Normal surface convexity may become flattened or concave (see arrow), and tooth decay (caries) may or may not be present, depending on the patient’s oral hygiene.
Another non-bacterial source of acid that can be destructive to the teeth is stomach acid (hydrochloric acid). Bulimic patients and those with gastro-esophageal reflux disorder (GERD) are at risk for the destruction of their teeth from their own stomach acid. Edentulism (complete tooth loss) can result if the cause is not brought under control.
The lower six-year molars of the patient in Figure 2 have been eroded by stomach acid. This patient suffered from chronic GERD. GERD can predispose patients to esophageal cancer, and when suspected should be diagnosed and treated by a physician. Dentists can observe this pattern and make an appropriate referral to a gastroenterologist physician for evaluation. Note that The 12-year molars are not as involved, for two reasons. First, they had been in the mouth for less than two years when the condition was diagnosed; second, they have been protected from stomach acid by the tongue, which falls back in the mouth when the patient is sleeping.
The term “idiopathic erosion” is used when specific causes for the observed erosion cannot be identified. Such cases can be frustrating for the dentist and the patient, because the success of treatment is difficult to predict.