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Dental Tribune United Kingdom Edition

13Endo TribuneNovember 2013United Kingdom EditionUnited Kingdom Edition Shattering the status quo 01733 315203 Shattering the status quo E L E V A T I N G D E N T I S T RY 541C 01733 315203 Be among the first to see the NEW XV1 from Orascoptic. Call 01733 315203 or visit The world’s FIRST wireless loupe + headlight in one N EW XV1_Shattering_UK_A4.indd 1 2/26/13 3:11 PM irrigant system.61–63 The apical va- pour lock may also explain why in a number of studies investiga- tors were unable to demonstrate a clean apical third in sealed root canals.59,64–66 In a paper published in 1983, based on research Chow deter- mined that traditional positive- pressure irrigation had virtually no effect apical to the orifice of the irrigation needle in a closed root canal system.67 Fluid ex- change and debris displacement were minimal. Equally important to his primary findings, Chow set forth an infallible paradigm for endodontic irrigation: “For the solution to be mechanically effec- tive in removing all the particles, it has to: (a) reach the apex; (b) create a current (force); and (c) carry the particles away.”67 The apical vapour lock and considera- tion for the patient’s safety have always prevented the thorough cleaning of the apical 3mm. It is critically important to determine which irrigation system will effec- tively irrigate the apical third, as well as isthmuses and lateral ca- nals,16 and in a safe manner that prevents the extrusion of irrigant. Manual agitation techniques By far the most common and conventional set of irrigation techniques, manual irrigation in- volves dispensing of an irrigant into a canal through needles/ cannulae of variable gauges, ei- ther passively or with agitation by moving the needle up and down the canal space without bind- ing it on the canal walls. This al- lows good control of needle depth and the volume of irrigant that is flushed through the canal.9,63 However, the closer the needle tip is positioned to the apical tissue, the greater the chance of apical extrusion of the irrigant.67,68 This must be avoided; were NaOCl to extrude past the apex, a cata- strophic accident could occur.69 Manual-dynamic irrigation Manual-dynamic irrigation in- volves gently moving a well-fit- ting gutta-percha master cone up and down in short 2-3mm strokes within an instrumented canal, thereby producing a hy- drodynamic effect and significant irrigant exchange.70 Recent stud- ies have shown that this irrigation technique is significantly more ef- fective than automated-dynamic irrigation and static irrigation.9,71,72 Machine-assisted agitation sys- tems Sonic irrigation - Sonic activation has been shown to be an effec- tive method for disinfecting root canals, operating at frequencies of 1-6kHz.73,74 There are several sonic irrigation devices on the market. The Vibringe allows de- livery and sonic activation of the irrigating solution in one step. It employs a two-piece syringe with a rechargeable battery. The irrigant is sonically activated, as is the needle that attaches to the syringe. The EndoActivator is a more recently introduced sonically driven canal irrigation system.9,75 It consists of a port- able handpiece and three types of disposable polymer tips of dif- ferent sizes. The EndoActivator has been reported to effectively clean debris from lateral canals, remove the smear layer, and dis- lodge clumps of biofilm within the curved canals of molar teeth.9 Ultrasonics - Ultrasonic energy produces higher frequencies than sonic energy but low amplitudes, oscillating at frequencies of 25- 30kHz.9,76 Two types of ultrasonic irrigation are available. The first type is simultaneous ultrasonic instrumentation and irrigation, and the second type is referred to as passive ultrasonic irrigation op- erating without simultaneous irri- gation (PUI). The literature indi- cates that it is more advantageous to apply ultrasonics after comple- tion of canal preparation rather than as an alternative to con- ventional instrumentation.9,20,77 PUI irrigation allows energy to be transmitted from an oscillat- ing file or smooth wire to the ir- rigant in the root canal by means of ultrasonic waves.9 There is con- sensus that PUI is more effective than syringe needle irrigation at removing pulpal tissue remnants and dentine debris.78–80 This may be due to the much higher veloc- ity and volume of irrigant flow that are created in the canal dur- ing ultrasonic irrigation.9,81 PUI has been shown to remove the smear layer; there is a large body of evidence with different con- centrations of NaOCl.9,80–84 In ad- dition, numerous investigations have demonstrated that the use of PUI after hand or rotary instru- mentation results in a significant reduction in the number of bacte- ria,9,85–87 or achieves significantly better results than syringe needle irrigation.9,84,88,89 Studies have demonstrated that effective delivery of irrigants page 14DTà