Extrinsic Dental Erosion - Causes and Diagnosis

Dental erosion is characterized by the irreversible loss of tooth structure caused by a chemical substance. It can inherently be classified as either extrinsic or intrinsic erosion.

So let’s start by defining the word “extrinsic”: Extrinsic is an adjective that denotes “something that is not part of the essential nature of someone or something.” It means it is coming or operating from the “outside.”

So these external “causes” of dental erosion can be divided under the following categories:

• Environmental causes
• Medications
• Lifestyle causes
• Dietary

Environmental factors mainly involve those workers exposed to acid fumes in factories without proper safeguards or exposure to swimming pools where the water has low pH due to inadequate maintenance. Now, as far as medications that may cause dental erosion, it has been found that young patients with juvenile rheumatoid arthritis taking a high dosage of aspirin and/or patients that take large amounts of ascorbic acid have shown dental lesions that are consistent with erosion - so, of course, these are also low pH medications.

Now when it comes to lifestyle, these type of erosive lesions have also been found in patients that have exaggerated - almost obsessive - use of some oral hygiene products.

The dietary factors have received the most attention and would be likely to affect the broadest segment of the population. We know that most acidic foods and drinks have the potential to cause dental erosion. The total acid level in our diet is considered more important than the pH, because it will determine the actual hydrogen available to interact with the tooth’s surface.

Interestingly, we can sometimes see dietary and lifestyle causes combined in individuals that have erosive lesions in only one side of the mouth. This may be explained by the fact that some patients like swishing highly acidic beverages. There are some individuals who simply don’t like the sensation of carbonated drinks when they swallow, so they will swish the soft drink around their mouth prior to swallowing. If they hold the liquid on one side, the wear will be greater on that side. These patients will also show erosive lesions on the facial surfaces of some teeth.

As erosion is manifested as wear of the dental substrate. It is not uncommon to misdiagnose it as attrition. As we know, attrition is defined by the tooth wear from teeth rubbing during mandibular movements, and typically we can single out three types of wear patterns:

1. Pathway wear
2. Edge-to-edge wear
3. Crossover wear

So the way to differentiate erosion from attrition lesions starts by looking at two things:

• The nature of the facets
• The location of the facets

As far as the nature of the facets goes, erosive lesions are typically:

• Cupped
• Satin-finished
• Rounded edges 

When we look at location, we can typically see these lesions away from areas of occlusal contacts (Fig 1).

That being said, it is not uncommon to see patients who may exhibit a combination of attrition and erosive lesions, which need to be perfectly diagnosed prior to treatment.

In this patient, (Fig 3 and 4) while the wear pattern was consistent with crossover wear from attrition, there was also a wear pattern at the facial aspect, consistent with erosion.

As we went through the health questionnaire, the patient admitted sucking on lemon for as long as he could remember. Minimally invasive preparations were made and the patient received ceramic veneers on both central incisors (Fig 5).

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Ricardo Mitrani, D.D.S., M.S.D., Spear Faculty and Contributing Author