This is the first in a three part series from the Chesapeake Dental Education Center (CDEC) covering the topic of treating the worn dentition. Part I will focus on diagnosis and etiology. Part II will cover esthetics – the first phase of treatment planning, and Part III will discuss occlusal issues relative to treatment planning.
Classically, in dental school, we are taught how to diagnose and treat periodontal disease and caries. In fact, dentistry has done such a good job treating dental disease and teaching preventative care that more and more people are keeping their teeth longer and longer. This has created an ever-increasing dilemma – more people with worn teeth and little to no dental school training in how to treat them.
As teeth wear, compensatory changes occur. Teeth will tend to stay in contact even thought they are diminishing in size. As teeth change their positions to stay in contact, the position of the entire alveolar housing surrounding them will change. Often, it becomes difficult to iminagine what the dentition looked like in youth, before the wear problem began. In other words, many of the wear cases are a problem of tooth position. And the two factors involved in determining ideal tooth position are esthetics and occlusion.
The first key in treating the worn dentition is diagnosing the etiology.
In our practice, we often see patients with moderate to advanced wear, that when asked about the condition of their teeth, tell us their previous dentist told them they grind their teeth. However, when we ask them about grinding, they tell us they were not aware of it.
Historically, tooth wear has been related to bruxisim. But now, it is commonly known there are other etiologic factors – erosion, both intrinsic and extrinsic, abrasion, abfraction and parafunctional habits other than bruxism. Properly diagnosing the etilogy allows both the dentist and the patient to understand the risk assessment of performing treatment.
Etiologic Factors in the Worn Dentition:
- Attrition is the loss of tooth structure by mechanical forces from opposing teeth. The most common cause of attrition is bruxism. Functional actions, such as chewing, speaking and swallowing usualy put very little force on the opposing teeth. Parafunctional habits, such as clenching and grinding, fingernail or cuticle biting, place greater amounts of force on opposing teeth.
- Erosion is the irreversible loss of tooth structure due to chemical dissolution by acids not of bacterial origin. The source of the acidity can be either extrinsic (like citris fruit or carbonated beverages), intrinsic (like gastric reflux or bulimia) or both.
- Abrasion is the loss of tooth structure by mechanical forces from a foreign element. If this force begins at the cemento-enamal junction, then progression of tooth loss can be rapid since enamel is very thin in this region of the tooth. Once past the enamel, abrasion quickly destroys the softer dentin and cementum structures.
- Abfraction is the pathologic loss of hard tooth substance caused by biomechanical loading forces. Such loss is thought to be due to flexural and chemical fatigue degradation of enamel and/or dentin from some location distant to the actual point of loading.
To determine which of these factors are involved when evaluating a patient with tooth wear, a careful patient history and clinical examination are necessary. Some wear patterns are pathognomonic and easily diagnosed (like bulimia). Other patterns are more difficult to diagnose (like non-carious cervical lesions) and can be multifactorial. By identifying the source or sources of wear, the patient can be counseled to eliminate or control them and understand the risks involved with either treatment or non-treatment of their wear.
Part II will focus on the esthetics of treating the worn dentition and expose portions of our Systematic Treatment Evaluation Protocol (STEPTM) that allows for an effecient and predictable process of determing…