Complications and procedural mishaps during root canal treatment: Part I

Abstract

It has been pointed out many times that endodontic therapy is directed towards elimination and prevention of apical periodontitis; it appears that antimicrobial efficacy is directly related to endodontic outcomes. Hence a lot of effort is currently spent in research and development to increase antimicrobial efficacy. New disinfection solutions and adjuncts such as sonic and ultrasonic irrigation tips and even new irrigation concepts such as negative pressure irrigation have been introduced. All of this is directed towards reducing the number of unfavorable outcomes, that is post-treat-ment disease. This strategy is justified by evidence confirming the microbiological basis for periapical periodontitis; in this sense, these new technologies all address the biological basis for problems with endodontic therapy. However, this is true following optimal treatment progress; unfortunately, there is a multitude of daily occurring technical issues that are less than optimal and are worthwhile reviewing. This issue of Endodontic Topics is dedicated to the most frequent and relevant of these clinical problems. Our patients bring in a variety of teeth with vastly different canal configurations. While we know at least theoretically what is possible in this regard, it is safe to assume that thousands of root canal treatments are performed every year in which canal anatomy is insufficiently dealt with. While we strive to reduce the microbial burden in the main canal and if at all possible in all of the root canal system, this is negated if a larger or smaller canal system is missed altogether. Hence, the technical nature of the error, missing anatomy, causes biological problems and contributes to a failing treatment. Perforation on access is another issue that is caused by our inability to address the anatomical variations adequately and has as much potential to reduce outcomes as the problem discussed previously. While magnification, ultrasonic tips for preparation, and burs with non-cutting tips go a long way towards optimiz-ing access cavity design, perforations on access are still frequent. With the development of MTA (ProRoot, Dentsply Tulsa Dental, Tulsa, OK, USA), a material is finally available that allows perforation repair in many clinical situations. However, handling of MTA remains a challenge, and the mechanism of action of MTA is not understood in detail and is therefore reviewed in this volume. It has been pointed out that ledging is one of the great challenges in endodontics (1) and this can surely be supported by generations of dental students and endodontic residents. In fact, ledging and blockage are both commonplace in situations that many specialists see in their daily practices, namely in endodontic re-treatment. Furthermore, we can infer that the inability to adequately disinfect after canal ledging and blockage contributes to inferior outcomes and in fact the need for re-treatment. Ledging can be viewed as a preparation error and indeed one possible end point of canal transportation. Of course there are much more discrete stages that a transported canal may be in. A recent unpublished survey found that many endodontists are concerned about preparation errors with nickel–titanium instru-ments, but clearly the quality of shaping has improved significantly with the advent of rotaries. Consequently, this issue includes a paper reviewing the mechanisms that may, and with other instruments may not, lead to canal transportation. Moreover, some canal trans-portation may be a good thing, specifically in the coronal third of the root canal with non-round cross-sections.