I clinical report _ shaping system Fig. 8 Fig. 9 Fig. 8_A mandibular molar shaped with two GTX Files in the mesial canals and a single 30/.08 GTX File in the distal canal; note the excellent 3-D cleaning and filling of lateral canals. (Courtesy of Dr David Rosenberg) Fig. 9_Maxillary molar with severe curvature in all four canals; note the conservative coronal shapes, the excellent apical control, and the multiple lateral canals cleaned and filled. This is an excellent clinical result requiring only two GTX Files per canal. (Courtesy of Dr David Rosenberg) his very conservative coronal shapes through which he uses carrier-based obturation to fill with excellent apical results. The final two cases (Figs. 8 & 9) were treated by Dr Rosenberg. In his case notes, he stressed that he spent much time creating ideal access cavity preparations prior to instrumentation, with special emphasis on creating straight-line glide paths for files, so that they do not accumulate cyclic fatigue stresses in the coronal third. He assured me that he no longer uses Gates–Glidden Burs for his approach and instead uses ultrasonic tips and an LAX diamond bur (SybronEndo), where it fits without overenlargement of orifices. Dr Rosenberg also instruments to a #20 K-file size in small canals before cutting GTX Files to length (more handwork than I do), but as a result he usually gets the 20/.06 GTX File to length without using a 20/.04 GTX File. If he has difficulty working a #20 K-file to length in a tightly curved canal, he cuts to shape in the coronal third with a 20/.06 GTX File and then with the #20 cuts to length with less effort. Occasionally, he will use a 20/.04 GTX File when a 20/.06 GTX File resists placement. In medium or large canals, he works progressively larger K-files to length until the first one binds at length (usually a #30 or #40), and then cuts to shape with a 30/.08 or 40/.08, respectively. Like me, both of these clinicians use rotary files only in a single tooth before they are discarded. We know that the cost of tracking previous file use, or worse a file separation, is never worth the cost of a new file being brought into the case. _Conclusion What is seen in all of these cases instrmented using just one to three GTX Files per canal is ideal apical management, both in terms of fidelity to the original canal path and in terms of apical accuracy and three-dimensionality of obturation. We see shapes that are confluent with the original curvature of the canals with teeth with their structural integrity intact after endodontic therapy for the best chance of an excellent longterm prognosis. In my opinion, the shaping results with GTX Files shown here are a 10x improvement over shaping file systems requiring four to six instruments, twice the number of procedural steps, laborious anti-curvature brushing motions to make up for large MFD sizing, and less than predictable avoidance of transportation. The state-of-theart endodontic shaping is now a two-file reality, allowing more time for things like negotiating all canals to their termini and effective irrigation._ This article is dedicated to the memory of Dr David Rosenberg, a friend, colleague, devoted husband and loving father. _about the author roots Dr L. Stephen Buchanan is a Diplomate of the American Board of Endodontics and a Fellow of both the International College of Dentists and American College of Dentists. Clinicians interested in his DVD series, The Art of Endodontics, and his hands-on laboratory workshops in Santa Barbara, USA, can call +1 800 528 1590. For more information related to this article and for GTX updates and answers to frequently asked questions, please visit www.endobuchanan.com. Free CE online courses are also available on the GTX System and other topics. 10 I roots 4_ 2009