Endo Tribune United Kingdom Edition

ENDOTRIBUNE The World’s Endodontic Newspaper · United Kingdom Edition Published in London www.dental-tribune.co.uk Vol. 9, No. 6+7 WAVEONEGOLD Dr Julian Webber explains why shaping canals with confidence is now a clinical reality for all. ” Page 17–20 INTERVIEW Patric Charest about the EyeZoom and the benefits it offers com- pared with conventional loupes. ” Page 21 SINGLE-USEINSTRUMENTS The One Shape Procedure Pack from Micro-Mega: A unique solu- tion for root canal shaping. ” Page 22–23 The mechanical and biological ob- jectives of shaping root canals were beautifully described by Herbert Schilder in 1974.1 As relevant today, in the era of automated canal prepa- ration techniques,as they were in the days of hand preparation techniques, theseobjectivesprovidetherationale for the designs,tapers and tip sizes of modern-dayendodonticinstruments. Shaping the root canal facilitates 3-Dirrigationandcleaningoftheroot canal system of all pulp tissue, bac- teria and their related by-products.2 Importantly, shaping the root canal provides the resistance form and fa- cilitatesfillingtherootcanalsystem.1,3 From hand to rotary When manually shaping canals with multiple sequences of stain- less-steel files and Gates Glidden Drills, root canal preparation tech- niques, old and new, have many de- ficiencies and iatrogenic problems, such as blocking, ledging, trans- portationandperforation,arecom- mon.4 The use of nickel-titanium (NiTi) files in continuous rotation driven by a dedicated endodontic motor capable of speed and torque control maintains the original pathway of the canal while limiting the amount of apically extruded debris.5,6 However, while the advan- tages of continuously rotating NiTi files are many, all commercially availablefilesystemsareinfluenced by cyclic fatigue and torque, espe- cially in longer, narrower and more curvedcanals. Cyclic fatigue, caused by the structuralalterationandworkhard- ening of the metal, is induced by re- peated tensile–compressive stress, especially when preparing canals exhibiting curvature.7 Torsional failure caused by using too much apical force occurs more frequently than flexural fatigue.8 Specifically, taper lock results when an exces- sive length of a file’s active portion binds in the canal during rotation. Undesirable taper lock promotes torsional failure and file breakage. When the canal diameter is nar- rower than the diameter of the rotating file, the latter has limited ability to progress deeper into the canal, binds and then potentially unwindsand/orbreaks.9 From rotary to reciprocation While the majority of commer- cially available NiTi systems are mechanically driven in continuous rotation, reciprocation—defined as any repetitive up and down or forward and reverse movement— has been used to drive endodontic instruments since 1958. Early at- tempts at reciprocation utilised alternating, but equal, forward and reverse angles of either 90 degrees or, more recently, smaller angles of 30 degrees. As such none of these instruments ever complete a full rotation.Althoughthesereciprocat- ing systems offer an alternative to manual preparation, multiple-file sequences, apical transportation, reduced cutting efficiency, inward pressureandlimiteddebrisremoval remain issues.5,10 However, with a novel reciprocating movement of unequal bidirectional angles that complete a full forward rotation of 360 degrees after four 90-degree cutting cycles of reciprocation, just 1a 1b 2 Fig. 1a: WaveOne GOLD ﬁle series, Small, Primary, Medium and Large.—Fig. 1b: WaveOne GOLD ﬁles have variable and reducing tapers, producing a more con- servatively shaped canal compared with their WaveOne predecessor.—Fig. 2: The cross-sectionofWaveOneGOLDisaparallelogramwithan85-degreeactivecutting edge with alternate one and two point contact.—Fig. 3a: WaveOne GOLD tip and proﬁle.—Fig.3b:WaveOne GOLD ogival tip design. Shaping canals with conﬁdence: WaveOneGOLDsingle-ﬁlereciprocatingsystem By Dr JulianWebber,UK 4 5 6 Fig.4:TheWaveOne GOLD ﬁle engages 150 degrees CCW and 30 degrees CW,turning 360 degrees after three cycles of reciprocation.—Fig.5:The new X-Smart iQ motor operated by the DENTSPLY iOS app downloaded on to an iPad mini 2 is a full digital solution with a cordless Bluetooth 8:1 reducing handpiece. 3a 3b 456

Endo Tribune United Kingdom Edition

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