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Abstract: Introduction: Complete endodontic system disinfection requires the removal of vital and necrotic pulp tissue, microorganisms, and toxins. The purpose of this study was to compare the effects of 2 ultrasonic irrigation techniques on the penetration of sodium hypochlorite into the main canal and simulated lateral canals of extracted teeth. Methods: Two simulated lateral canals each were created 2, 4, and 6 mm from the working length in 60 single-rooted teeth (6 canals/tooth, n = 360). To resemble the clinical situation, a closed system was created in each tooth. The teeth were randomly assigned to 3 experimental irrigation groups: group 1 (n = 20), positive pressure irrigation (PPI); group 2 (n = 20), passive ultrasonic irrigation (PUI); and group 3 (n = 20), continuous ultrasonic irrigation (CUI). Samples were evaluated by direct observation of still images recorded under a dental operating microscope. To examine irrigating solution penetration, 20% Chinese ink (Sanford Rotring GmbH, Hamburg, Germany) was added to a 5% sodium hypochlorite solution and delivered into the root canals. Results: The results showed a significantly higher (P < .05) penetration of irrigant into the lateral canals in the CUI group. PUI and CUI did not differ significantly in solution penetration into the apical thirds of the main canals. The PPI group showed a significantly lower penetration of sodium hypochlorite into the main and lateral canals compared with the CUI and PUI groups. Conclusions: CUI as a final rinse significantly increased the penetration of irrigating solution into simulated lateral canals. [Copyright &y& Elsevier]

The field of endodontics has seen vast improvements in technology and techniques over the past several years. Perhaps the one area of endodontics that has improved the most is the way in which surgery is performed. With the use of state-of-the-art instruments, new and improved materials, and a surgical operating microscope, the gap has narrowed between biological concepts and the ability to achieve consistently successful clinical results. The practice of these techniques is now referred to as endodontic microsurgery. [ABSTRACT FROM AUTHOR]

Suter B, Lussi A, Sequeira P.Probability of removing fractured instruments from root canals.International Endodontic Journal,38, 112–123, 2005.To evaluate in a clinical case series the location of fractured instruments, how many of them could be removed and to compare these findings with the results of a similar study.Within an 18-month period all referred endodontic cases involving fractured instruments within root canals were analysed. The protocol for removal of fractured instruments was: create straight-line access to the coronal portion of the fractured instrument, attempt to create a ditched groove around the coronal aspect of the instrument using ultrasonic files and/or to bypass it with K-Files. Subsequently, the fractured instrument was vibrated ultrasonically and flushed out of the root canal or an attempt was made to remove the instrument with the Tube-and-Hedström file-Method or similar techniques. The location of the fractured instrument and the time required for removal were recorded. Successful removal was defined as complete removal from the root canal without creating a clinically detectable perforation.In total, 97 consecutive cases of instrument fracture were included in the time period. In all, 84 instruments (87%) were removed successfully. There was a significant correlation between the time needed to remove fractured instruments and a decrease in success rate. Curved canals had significantly more fractured instruments than straight canals (P < 0.05). Rotary instruments fractured significantly more often in curved canals (P < 0.05) compared with other instruments. Half of all instrument fractures occurred in mesial roots of lower molars and most often when using rotating instruments. There was no statistically significant difference in the success rate with respect to the location of the fractured instrument (tooth/root type), the type of fractured instrument or the different methods of instrument removal.Curved canals are a higher risk for instrument fracture than straight canals. In curved canals rotary instruments (including lentulo spirals) fractured more often than other instruments. In all, 87% of the fractured instruments were removed successfully. A decrease in success rate was evident with increasing treatment time. The use of an operating microscope was a prerequisite for the techniques used to remove the fractured instruments. [ABSTRACT FROM AUTHOR]

Thorough knowledge of aberrant root canal anatomy is critical for successful endodontic treatment. Many case reports of middle mesial canal in mandibular first molar have been published, however presence of middle distal canal in distal root of mandibular first molar is rare. This case report describes successful endodontic management of a mandibular first molar with five root canals (two mesial and three distal canals). The use of an operating microscope for detection of additional root canal orifices in complicated cases is recommended. [ABSTRACT FROM AUTHOR]