Endo Tribune United Kingdom Edition

Endo Tribune United Kingdom Edition | 6+7/201518 one single file can start and fully complete the preparation of a canal toaperfectshape.11 Asingle-filetech- nique in conjunction with a novel reciprocating movement has been clearly shown to reduce both cyclic fatigue and torsional failure, pre- ventingbrokeninstruments.12 In 2008, the concept of the “single-file technique” was adopted by DENTSPLY International as a project in collaboration with eight international clinicians to produce a more optimal, dedicated, safe, unique reciprocating single file and to identify the most suitable unequal bidirectional angles with a motor system to generate this movement. The outcome was the launch of RECIPROC (VDW) in 2010 and WaveOne (DENTSPLY Maillefer) in2011.Bothsystemsweremarketed as simple, efficient and predictable automatedmethodstoshapecanals andembracedbymanygeneralden- tal practitioners looking to move into automated canal shaping after yearsofunsuccessfulattemptswith manualtechniquesandvaluedboth intermsoftimeandcostsavings. WaveOne and RECIPROC file sys- tems (reciprocating files) demons- trateconsiderablyimprovedmechan- ical properties, superior to rotary files. While the cyclic fatigue prop- erties of RECIPROC are superior to WaveOne, the resistance to torsional failure of WaveOne is superior to RECIPROC.13,14 Overall, reciprocating filesaremoreresistanttofracturethan are continuously rotating files,15 ex- trudelessdebristhandoconventional multiple-filerotarysystems16 andeli- minate bacteria from root canal sys- temsasefficientlyasrotarysystems.17 The shaping ability of reciprocating files is as good as and in many cases betterthanrotaryfiles.18 Finally,itcan be clearly stated that reciprocating filesdonotinducedentinecracks.19 WaveOne and RECIPROC were designed as true single-use instru- ments that cannot be sterilised and re-used. The ISO colour-coded ABS ring on the handle expands if ster- ilised and the file will not fit into its handpiece. Single use is based on sound scientific facts and common sense,aseliminationofrepeateduse decreases the possibility of fracture due to both fatigue and torsional failure.20 The inability to consis- tently clean and sterilise used in- struments eliminates any concerns about cross-contamination,21 and disposal after single-patient use eliminates the cost of disinfecting, cleaning and sterilising, reducing costsoverall.22 However,itshouldbe understood and fully appreciated that a single reciprocating file per- formsthesametaskthatwouldtyp- ically require three or more rotary NiTi files to accomplish. Logic dic- tatesthatsingleuseisbyfarthebest solution to reducing the incidence of file breakage with all its ethical, emotional and malpractice ramifi- cations. New developments With today’s increased focus on minimallyinvasiveendodontics,23 the conclusions from the literature and taking into account feedback from cliniciansusingWaveOnesinceitsin- troductionin2011,fouroftheoriginal opinionleadersinvolvedintheinitial development of the file, Drs Clifford Ruddle (US), Sergio Kuttler (US), Wilhelm Pertot (France) and Julian Webber(UK),workedincollaboration with the research and development team at DENTSPLY in Ballaigues, Switzerland, to further improve the cutting efficiency and mechanical properties of the file and give a new levelofconfidencetothemanyclini- cians still wary of automated tech- niquesforshapingcanals. The result is the recent launch of WaveOneGOLD,anewgenerationof reciprocating files offering simplic- ity, safety and single use in shaping canals. Advanced metallurgy WaveOne GOLD instruments are manufactured utilising a new DENTSPLY proprietary thermal process, producing a super-elastic NiTi file. The gold process is a post- manufacturing procedure in which the ground NiTi files are heat- treated and slowly cooled. From a technical perspective, the heat treatmentmodifiesthetransforma- tion temperatures (austenitic start andausteniticfinish),andthishasa positive effect on the instrument properties.24,25 While this process gives the file its distinctive gold finish, more importantly, it consid- erably improves its strength and flexibility far in excess of its prede- cessor. DENTSPLY internal testing has shown the following: the cyclic fatigue resistance of WaveOne GOLDPrimaryis50percentgreater than that of WaveOne Primary (which itself was twice as great as most standard rotary file systems), and the flexibility of WaveOne GOLDPrimaryis80percentgreater thanthatofWaveOnePrimary.26 Design features There are four tip sizes in the WaveOne GOLD single-file recipro- catingsystem:Small(20.07,yellow), Primary(25.07,red),Medium(35.06, green) and Large (45.05, white) (Fig.1a),availablein21,25and31mm lengths. The various tip sizes and tapersaffordthecliniciantheability toclinicallyprepareawiderrangeof apical diameters and endodontic anatomy commonly encountered in daily practice.27 Canal prepara- tions that have sufficiently tapered resistanceformareidealforirrigant exchange and removal of debris,28 thus promoting 3-D disinfection andfillingoftherootcanalsystem. WaveOneGOLDhasactivecutting lengths of 16 mm, shortened 11 mm handles for improved posterior access and the same expanding ISO colour-coded ABS ring as WaveOne, maintaining the philosophy of singleuse.Variableandreducingta- pers ensure a more conservatively shaped canal with greater preser- vation of tooth structure at D16, the coronal extent of the prepara- tion (Fig. 1b). While the concepts of “minimally invasive endodontics” lack documented and meaningful studies,29 anyshapingobjectivethat removes less of the existing tooth structurewhileoptimisingefficient 3-D irrigation and obturation is a positivestepinanefforttopreserve theintegrityofthenaturaltooth. The cross-section of WaveOne GOLD is a parallelogram with two 85-degree cutting edges in contact withthecanalwall,alternatingwith a patented DENTSPLY off-centred cross-section where only one cut- tingedgeisincontactwiththecanal wall (Fig. 2). Decreasing the contact area between the file and the canal wall reduces binding (taper lock) and, in conjunction with a constant helical angle of 24 degrees along the active length of the instrument, ensures little or no screwing in. The additional space around the instru- ment also ensures additional space for improved debris removal. The tipofWaveOneGOLD(Figs.3a&b)is ogival, roundly tapered and semi- active, modified to reduce the mass of the centre of the tip and improve its penetration into any secured canalwithaconfirmed,smoothand reproducibleglidepath. Collectively,thesedesignfeatures result in a reciprocating movement thatisverysmooth,eliminatingthe needtopushonthefile,andthereby promoting safety and considerably improving cutting efficiency. This ENDO NEWS • Always initiate shaping procedures withWaveOne GOLD Primary. • Irrigateabundantlyandfrequentlywithsodiumhypochloriteafterremoving any givenWaveOne GOLD file from a canal. • Remove the WaveOne GOLD file when it does not easily progress. Clean and inspect the cutting flutes for wear and/or distortion and then irrigate, recapitulate with a #10 hand file and re-irrigate. • Owing to the unique WaveOne GOLD post-manufacturing process, the files may appear to be slightly curved. This is not a defect and it is not necessarytostraightenthefilebeforeuse.Placethetipofthefileinthecanal entrance and start the motor.The file will follow the glide path conforming to the natural curvature. The advantage is that a slightly curved file can be more easily placed into canals of posterior teeth where access is restricted. Table I:WaveOne GOLD tips. Fig.6: Summary of theWaveOne GOLD shaping technique:80 per cent of cases start and ﬁnish with the Primary ﬁle.At completion of shaping,gauging with hand ﬁles or inspecting ﬂutes for debris conﬁrms whether either the Medium or the Large ﬁle is needed.—Fig. 7a: WaveOne GOLD procedural ﬂow chart where a #10 hand ﬁle is able to establish length: conﬁrm patency and verify the glide path. ProGlider will expand any conﬁrmed,veriﬁed and reproducible glide path prior to the shaping procedure with the Primary ﬁle.(Rx:radiograph;AL:apex locator;IRI:irrigate,recapitulate and irrigate again).—Fig.7b:WaveOne GOLD procedural ﬂowchart formorerestrictivecanals:usea#10handﬁleinanyregionof thecanal tocreateaglidepath.ProGliderwillexpandanyconﬁrmed,veriﬁedandreproducibleglidepath.—Fig.7c:WaveOneGOLDprocedural ﬂow chart when the Primary ﬁle does not progress:use the Small ﬁle in one or more passes to working length and then use the Primary ﬁle to working length to optimise the shape.—Fig.8: A ProGlider progressing apically expands the glide path.—Fig. 9: WaveOne GOLD Primary progressing apically through the expanded glide path.—Fig. 10: WaveOne GOLD Primary at full working length.—Fig. 11: WaveOne GOLD Primary loaded with debris,especially in the apical extent of the ﬁle,indicating that full shape has been achieved. Fig. 12: WaveOne GOLD obturating solutions with matching paper points, gutta- percha points andThermaﬁl. 12 7a 7b 7c 8 9 10 11 891011

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