Dr. David Bartlett has published a fine review regarding the effects of acid on the tooth surface, "A New Look at Erosive Tooth Wear in Elderly People," in the September JADA "OralLongevity: Oral Health and the Aging Population" supplement (
Bartlett D. JADA 2007;138[supplement]:21S–25S
). However, he has made a few statements that need clarification. The title is misleading, for erosion as stated is a chemical mechanism, whereas wear is a physical mechanism caused by friction. In his abstract, he used the term "acid erosion" on three occasions, but only once does this expression occur within the article.
In my opinion, Dr. Bartlett is moving in the right direction, as he did preface the term "erosion" with the term "acid" to designate the effects from acid as opposed to the negligible effects of water flowing over teeth. Unfortunately, using the term "erosion" rather than "corrosion" negates the use of the mechanisms of stress and fatigue corrosion, which he ignores wherever occlusal forces occur. Figure 1 demonstrates a patient "holding oranges" (a static situation) against the teeth and calls it "erosion," which is a dynamic effect due to motion. Furthermore, he ignores the effects of stress from parafunction as a cofactor, which is evident from the even wear of the patient’s teeth.
In the 21st century, I contend that it is time to start using a more precise language to designate chemical degradation and supplant the term "erosion" with "corrosion." The combined mechanisms of stress (static) and fatigue (dynamic) corrosion have been in use by the engineering profession for many years and should be embraced in the lexicon of dental terms. Dr. Simring, Dr. Schreiner and I proffered these mechanisms to the profession in our August 2004 JADA article.1 However, there are still those who remain fixed to the outdated and confusing terminology of the past.
The combined mechanisms of stress (static) and fatigue (dynamic) corrosion have been in use by the engineering profession for many years and should be embraced in the lexicon of dental terms.
Dr. Bartlett misquoted the term "abfraction" as it was used in our August 2004 article.1 The loss of tooth substance by abfraction is not, as was stated, tooth wear, which is caused by the mechanism of friction. It occurs in any area of stress concentration, usually acting in concert with an acid and is frequently exacerbated by toothbrush/dentifrice abrasion, thus being a multifactorial event. Abfractions from occlusal loading as a cofactor are most commonly seen in the cervical region, but they also occur on the occlusal surface as Class VI lesions, on the facial and lingual surfaces and, occasionally, on the interproximal surfaces.
The etiology of abfractive lesions is done inferentially by using the accepted and proven mechanisms of stress, friction and corrosion, most often working in concert or sequentially. The only instance I have seen clinically of an abfraction solely occurring was in a well-placed gold foil, done by a dental school professor, that was breaking down as a result of parafunction.
It is hoped that these comments will stimulate more interest in correcting the misnomers that exist to this day, for we will not progress in our quest for answers until this is accomplished and precise terms are embraced by our profession. Dental school teachers, researchers and clinicians must be more receptive to the reality of the mechanism and effects of stress, both during static and dynamic situations. Furthermore, the acceptance of the term "corrosion" will open the door to the mechanisms of both stress and fatigue corrosion, which are common occurrences in the clinical situation.
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