Cognitive dissonance in endodontics.

Cognitive dissonance is the existence of views, attitudes, or beliefs which are inconsistent or incompatible with one another but, nonetheless, are held simultaneously by the same person. In a penetrating article, Edwin G. Boring (1), Edgar Pierce Professor of Psychology Emeritus at Harvard University, has documented the existence of cognitive dissonance among scientists who, after all, he said, turn out to be human. One of the graphic examples offered is the persistence of smoking, despite evidence that it is hazardous to life itself. To rationalize, the smoker must change his cognition, thereby minimizing the scare about lung cancer, suppress or ignore the dissonance, or change his behavior by giving up smoking. Is cognitive dissonance present in endodontics? It is our belief that, as scientific evidence accumulates, a greater and greater dissonance is emerging in both the theory and the practice of endodontics. At least, this is true for us, and we would like to share our dissonance with others in the scientific community who perhaps have similar but unexpressed views. It has long been held that if the three basic principles—the so-called “endodontic triad”—are followed faithfully, the end result of endodontic treatment must be successful (2). These three “principles” are (a) thorough debridement of the root canal, (b) sterilization of the root canal, and (c) complete obturation of the root canal. Put down as a simple formula, it would be a! b! c" endodontic success. In endodontic therapy, the a ! b ! c formula for success has been taught in most dental schools as the only sure way to achieve a lasting and permanent result. Deviations from this formula are almost certain to result in failure. So far, no dissonance. However, some dissonance begins to creep in when the dental student or general practitioner (or even the experienced endodontist, for that matter) follows the a ! b ! c formula and failure ensues (Fig. 1). Usually, the dissonance is resolved quickly by the rationalization that, somehow, there has been a break in adherence to the a! b ! c formula. For example, maybe a small amount of necrotic tissue was left in the root canal and somehow escaped being removed, or perhaps the negative culture obtained was a false negative and there were some microorganisms lurking in hidden recesses just waiting for the opportunity to emerge and “vent their spleens” on the periapical tissues after treatment was completed. Perhaps the canal was not completely obturated and there were minute voids between the root filling and the dentinal wall, or perhaps the canal was overfilled and the filling material was irritating. The possibilities are numerous. Conversely, dissonance also arises when, through intention or neglect, the formula is not followed and success results anyway (Fig. 2). How can this be explained rationally? The cognitive dissonance rears its ugly head when we examine each part of the triad, as we shall now do.