The review and "re-evaluation" of noncarious cervical lesions by Dr. Luis Litonjua and colleagues is a rehash of old arguments that render the subject unnecessarily complicated and confusing ("Noncarious Cervical Lesions and Abfractions: A ReEvaluation," July JADA).
The article seems to convey the impression that noncarious cervical lesions are a single entity, not unlike the old concept that periodontal disease is a single disease. Therein lies the crux of the article’s argument and confusion. I am not aware of any leading investigator in the field advocating a sole single cause of all noncarious cervical lesions. Multifactorial etiology is the prevailing view for many lesions.
The vast majority of noncarious cervical lesions can be adequately explained by stress damage or toothbrush abrasion, or a combination of both of these factors.
The stress theory put forth two decades ago was based on the centuries-old universal observation that stress, particularly repetitive stress of sufficient magnitude, causes damage to structure of matter. Engineers call it structural fatigue. It is not at all surprising that, under repetitive occlusal stress, tooth structure suffers from the same structural fatigue at areas of stress concentration. Stress-damaged tooth structure is more readily abraded away by toothbrushing. That, however, does not preclude the formation of lesions by toothbrush abrasion alone.
It is likely that many non-carious cervical lesions are the result of a combination of stress damage and toothbrush abrasion. The morphologic variability of the lesions may simply reflect the varied degree of damage due to stress and the effect of abrasive action.
The fact that tooth structure is stronger under compression than under tension forms the basis of the argument that tensile force is the main factor in cervical area stress damage.
With a clear understanding of stress damage and abrasion, the enigma of noncarious cervical lesions is not so enigmatic after all. The issue raised by the authors on whether stress-induced cervical lesions (abfractions) are a "distinct" clinical entity is more naïveté than legitimate scientific inquiry. The article conveys a lack of familiarity of the subject matter and a scarcity of clinical experience in the management of these lesions.
The relevancy of the issues raised in this re-evaluation is 20 years past. Progress in restorative dentistry is to be made in research on how to accommodate the damaging stresses. It is time to move on rather than re-fight the old battles.
