Please activate JavaScript!
Please install Adobe Flash Player, click here for download
ePaper created 2016-03-11, 23:13:06 | version 1.38.0
issue 2016 — 71 Endodontics Article Figs. 1 & 2 Ultrasonic activation with a passive file. theyreleaseimpactenergythatisrespon- sible for the detergent effect. It has been demonstrated that ultrasonic activation ofNaOCldramaticallyenhancesitseffec- tiveness in cleaning the root canal space, as ultrasonic activation greatly increases the flow of liquid and improves both the solvent and antibacterial capacities and the removal effect of organic and inor- ganic debris from the root canal walls.7 Ultrasonic activation of NaOCl of 30–60 s for each canal, with three cycles of 10–20 s (always using new irrigant), ap- pears to be sufficient time to obtain clean canals atthe end ofthe preparation phase (Figs. 1&2).7 Ultrasoundappearstobeless effective in enhancing the activity of EDTA, although it may contribute to bet- ter removal of the smear layer.7 The accu- mulation of debris produced by mechan- ical instrumentation in inaccessible areas is preventable by using ultrasonic activa- tionofNaOClevenduringthepreparation phase.8 The use of a system of ultrasonic continuous irrigation might therefore be advantageous.Itinvolvestheuseofanee- dle activated by ultrasound. With this method, the irrigant is released into the canal and is activated by the action of the ultrasonic needle simultaneously.9 — Chlorhexidine A final flush with 2% chlorhexidine (CHX) aftertheuseofNaOCl(todissolvetheor- ganiccomponent)andEDTA(toeliminate the smearlayer) has been proposedto en- sure good results in cases of persistent in- fection,owingtoitsbroadspectrumofac- tion and its property of substantivity.5, 10 However, the use of CHX is hindered by the interaction between NaOCl and CHX, which tends to create products that may discolor the tooth and precipitates that maybepotentiallymutagenic.Forthisrea- son, CHX should not be used in conjunc- tion with or immediately after NaOCl.11 This interaction can be prevented or min- imized by an intermediate wash with ab- solute alcohol, saline or distilled water.12 Activation systems Mechanicalinstrumentationalonecanre- duce the number of micro-organisms present withinthe root canal system even without the use of irrigants and intracanal dressings,13 but it is not able to ensure an effectiveandcompletecleaning.14 Irrigat- ingsolutionswithouttheaidofmechanical preparation are not able to reduce the in- tracanal bacterial infection significantly.15 For these reasons, today research is oriented toward the study of systems that can improve root canal disinfection through mechanical activation of en- dodontic irrigants, and in particular NaOCl. Multiple agitationtechniques and systems for irrigants have been used over time,16 demonstrating more or less posi- tive results.17 — Manual agitation techniques The simplest technique of mechanical ac- tivation of irrigants is manual agitation, which can be performed with different systems. The easiest way to achieve this effect is to move verticallyan endodontic file that is passive in the canal. The use of the file facilitates the penetration of the irrigant, leadsto a more effective delivery ofirriganttotheuntouchedcanalsurfaces and reducesthe presence of airbubbles in the canal space,18 but does not improve the final cleaning.17 Another similar tech- nique moves vertically a gutta-percha cone to working length with the canal Fig.1 Fig.2 Article_Plotino_00-00.qxp_Layout 1 02.03.16 22:18 Seite 2 Article_Plotino_00-00.qxp_Layout 102.03.1622:18 Seite 2