RO0211

I 25 case report _ endodontic zone I roots2_2011 I never do initial negotiation procedures with NaOCl irrigant in the access cavity. While all the current apex locators work in the presence of conductive fluids, none of them work as well as whenrelativelynon-conductivelubricantsareused instead. NaOCl short-circuits the apex locator to metallic restorations and even without metal nearby, the readings in the presence of this irrigant are much less stable. A note of caution: while non-landed shaping instruments are safe in the smallest sizes, I would not recommend using them for shaping canals. To prevent apical damage, I use only radial-landed rotary files (Fig. 9) to cut final shapes after initial negotiation. Final shapes were cut in the palatal canal with a single 30/.08 GTX File, with a 20/.06 and a 30/.06 GTX File in the DB canal, and three instruments in the apically curved MB canals. I cut a crown-down shape in these canals with first a 20/.06 and then a 20/.04 GTX File. After confirming that there was apical continu- ity of taper in each canal, by using NiTi K-files as radial feeler gauges—this is done in the presence of 17% EDTA (to remove the smear layer)—my efforts turned to cleaning the root-canal system with pre- heated 6% NaOCl. I began by ultrasonically vibrat- ingtheirrigantwitha#10K-filetaken1mmbeyond the terminus—this prevents the micro-ledging that occurs when the vibrated file tip is held inside the apical third—for a couple of minutes in each canal, and then switched to active irrigation with the negative pressure EndoVac System (Discus Dental). Despite heating the solution, using ultrasonica- tion and a state-of-the-art delivery method, in an inflamed vital case like this I still feel that the NaOCl needs additional time to digest any tissue that may remain in lateral and accessory canals. Failure to clean the lateral aspects of root-canal systems con- tainingseverelyinflamedpulpremnantsadequately is what causes some of these patients to complain of persistent pain to biting and percussion despite apparently ideal root-canal treatment results evi- dencing no peri-radicular pathosis. Obturation was accomplished after cleaning with theSystemB/ElementsObturationUnit(SybronEndo) usingtheContinuousWaveofObturationTechnique. Interestingly, when I was drying the palatal canal in preparation for cementing the pre-fit master cone of gutta-percha, the paper points were coming out soaked in blood. While this may be disconcerting to clinicians, it does not mean anything has necessarily gone awry, it just means that the bleeding must be stopped. I soaked a paper point in 30% ferric sulphate (known by the brand name Cutrol or the pharma- ceutical name Monsel’s Solution), placed it to the endofthecanalandabitbeyond,andafter10or15 seconds removed it, irrigated with NaOCl, gained patency with a K-file that could be passively placed beyondtheterminus,andresumeddryingthecanal. Sometimes this must be done two or three times to staunchbleeding,butIhaveneverseenitfail.Inthis case,whilethepaperpointstoppedabsorbingblood at its tip, it continued to show a spot of blood in the middle of the cone (Fig. 10). The post-operative X-ray images revealed a lateral canal filled in the middle of the palatal canal (Figs. 11 & 12). A piece of sponge and Cavit (3M ESPE) were placed in the access cavity and the patient was dismissed after post-operative images had been taken and instructions given. As usual, the patient also received enough Aleve to last four days at two tablets BID and instructions about managing her pain of myofascial origin (finally located as ema- Fig. 9_Rotary GTX File with variable- width lands—thinner at the tip and shank, thicker in its middle region. This geometry optimises the radial lands to cut much more efficiently than rotary files with consistent- width lands, while maintaining identical fidelity to canal curvatures. Fig. 10_Paper point used to dry the palatal canal, showing blood mark only on its middle region. Fig. 9 Fig. 10