Nickel–titanium Instruments In Endodontics: A Concise .
Critical ReviewEndodontic TherapyNickel–titanium instruments inendodontics: a concise review of thestate of the artGiulio GAVINI(a)Marcelo dos SANTOS(a)Celso Luis CALDEIRA(a)Manoel Eduardo de LimaMACHADO(a)Laila Gonzales FREIRE(a)Elaine Faga IGLECIAS(a)Ove Andrea PETERS(b)George Táccio de MirandaCANDEIRO (c)(a)Universidade de São Paulo – USP, Schoolof Dentistry, Discipline of Endodontics, SãoPaulo, SP, Brazil.(b)University of the Pacific, Arthur A. DugoniSchool of Dentistry, Department ofEndodontics, San Francisco, CA, United States.(c)Universidade Christus, Department ofDentistry, Post graduation Program in DentalSciences, Fortaleza, CE, Brazil.Declaration of Interests: Dr. Petersserves as a consultant for Dentsply Sirona.The remaing authors certify that they haveno commercial or associative interest thatrepresents a conflict of interest in connectionwith the manuscript.Corresponding Author:Giulio GaviniE-mail: -2018.vol32.0067Submitted: May 05, 2018Accepted for publication: May 29, 2018Last revision: June 11, 201844Braz. Oral Res. 2018;32(suppl):e67Abstract: The introduction of automated instrumentation in endodonticsrepresented a major advance in progress for this specialty, withimprovements in the quality and predictability of root canal preparationand a significant reduction in procedural errors. In recent years,endodontic instruments have undergone a series of changes broughtabout by modifications in design, surface treatments, and thermaltreatments. In addition, new movements have also been incorporated tooffer greater safety and efficiency, optimizing the properties of the NiTialloy, especially through eccentric rotary motion. An understanding ofthe mechanical properties of these new NiTi instruments and their effecton the clinical performance of root canal preparation is essential if dentalpractitioners are to select the instruments that provide optimal clinicaloutcomes, especially in curved or flattened canals. The objective of thisliterature review is to present and discuss the characteristics of the NiTialloys used in the major instrumentation systems available in the market,as well as the influence of the metallurgical and mechanical propertiesof NiTi instruments and the movements that drive them, to enable moreaccurate and predictable planning of root canal preparation.Keywords: Endodontics; Root Canal Preparation; Dental Instruments.IntroductionThe introduction of nickel–titanium (NiTi) alloys and the subsequentautomation of mechanical preparation were the first steps towards a newera in endodontics. These changes ushered in ever-greater progress in thespecialty, with scientific and corporate research focused on developinginstruments capable of meeting the needs for a more anatomically predictableroot canal preparation, achievable in less time and with greater comfortfor dentist and patient alike, as inflexible instruments have substantialdifficulty following the curvature found in most root canal systems.Over the last few years, many changes have been observed, includinginnovations in instrument design, surface and thermal treatments forNiTi alloys, and the incorporation and hybridization of new movementstrategies to drive instrumentation systems. Knowing the morphologicaland mechanical characteristics of endodontic instruments, as well astheir proper mode of use, provides greater security and versatility tothe operator.
Gavini G, Santos M, Caldeira CL, Machado MEL, Freire LG, Iglecias EF et al.Nickel–titanium alloy was originally developedfor the U.S. space program at the Naval OrdnanceLaboratory, in 1963, and was given the generic name“Nitinol”.1 In dentistry, it was first used in 1971 byAndreasen and Hilleman, 2 in the manufactureof orthodontic wires, due to its low modulus ofelasticity, shape-memory effect, and superflexibility.Specifically in endodontics, Civjan et al.3 were thefirst to conceptualize the fabrication of endodonticinstruments from NiTi alloy, in 1975. Later, in 1988,Walia, Brantley and Gerstein4 introduced the firsthandheld NiTi endodontic instruments, made bymachining orthodontic wire. Thereafter, technologicaladvances in the production of NiTi instrumentsallowed them to be manufactured by machiningprocesses with significant changes in the configurationof the active part, variations in the helical angle andcut angle, and different increases in taper withinthe same instrument, no longer following the ISOstandards published in 1958 for manual instruments.5For many years, these instruments were fabricatedexclusively through conventional machining, withvariations mainly in the design of the cross-section,arrangement of the cutting surfaces along the activepart, and presence or absence of radial surfaces; themajor objective was to improve the cutting propertiesof the instrument and, particularly, reduce its riskof fracture. In this sense, the NiTi alloy treatmentsintroduced since 1999 were the main factor responsiblefor changing the clinical behavior of these instruments.Currently, more than 160 automated instrumentationsystems are available, manufactured with differentNiTi alloys, heat-treated or otherwise, with bothsuperelastic (SE) and shape-memory (SME) properties,using rotational or reciprocating kinetics, centric oreccentric motion (Table). This paper aims to presenta review of automated NiTi endodontic instruments,their mechanical properties, and the particularfeatures of the main systems available today.Mechanical properties ofnickel-titaniumMost metallic materials exhibit an elastic behaviorin which, within certain limits, the deformation causedis directly proportional to the force applied. Thisrelationship is known as Hooke’s Law. If the forceapplied exceeds a certain limit, it causes permanentdeformation in the material (plastic deformation).According to Hooke’s Law, most metal alloys canbe elastically deformed by up to 0.1 or 0.2% beyondtheir elastic limit, or yield strength. Any deformationabove this limit, known as the yield point, will bepermanent. Nickel-titanium alloys, however, can bedeformed up to 8% beyond their yield strength withoutshowing any residual deformation.5,6 Superflexibility,or pseudoelasticity, can thus be defined as the abilityof certain materials to recover their original shapeafter the load is removed even when they are deformedbeyond their yield strength.7According to Thompson5, the special propertiesof NiTi alloys are associated with a solid-state phasechange: the martensitic transformation (MT). The MT isinduced by the application of stress or by a temperaturereduction, in which atoms move coordinately by ashear-type mechanism and are rearranged into a new,more stable crystalline structure, with no change inthe chemical composition of the matrix, but with amacroscopic change in the shape of the material.This transformation occurs between austenite (theparent phase) and martensite.When a material that undergoes MT is cooledbelow a certain temperature, the transformation isinitiated by a shear mechanism, as shown in Figure1. The martensitic regions in A and B have the samecrystal structure, but the spatial orientations of thecrystals are different.6In MT caused by the cooling of the specimen,there is no change in shape, as the transformationmechanism is one of reversible, ordered selfaccommodation.8 If the material is heated whilein the martensitic phase, the martensite becomesunstable, and reverse transformation (RT) occurs.The martensite thus returns to the austenite phase,and transformation follows the inverse path of MT.Another important point is the shape-memoryeffect (SME), which is the ability of the alloy tocompletely recover its original shape when heatedabove the martensite-to-austenite transformationtemperature, a temperature that varies according to thechemical composition of the alloy. Among the variousmetal alloys that exhibit superelasticity (SE) and theBraz. Oral Res. 2018;32(suppl):e6745
Nickel–titanium instruments in endodontics: a concise review of the state of the artTable 1. Features of the main automated instrumentation systems in the current world panorama.Instrument/Manufacturer (Year)Application/KinematicsCross-section/Special FeaturesDiameter/TaperShaping/Rotary centricTriangular with alternating cuttingedges along the instrument10–60Race/FKG (1999)IRace (2011)BioRace (2012)Series ISO 10 (2010)Glide path/RotarycentricQuadrangularScout Race (2014)Glide path/RotarycentricQuadrangularManufacturing/ Treatment.02, .04, .0610.02, .04, .0610, 15, 20.02Micromilling,ElectropolishingBT1 – 10.06BT Race (2014)Shaping/Rotary centricTriangular with alternating cuttingedges along the instrumentBT2 – 35.00BT3 – 35.04BT4 – 40.04BT5 – 40.04K3/Sybron Endo (2001)Shaping/Rotary centricK3XF (2011)Mtwo/VDW (2003)ProTaper Universal/Dentsply-Sirona (2006)Shaping/Rotary centric15–60Micromilling.04, .06Micromilling, R-PhaseS-shaped with two active cuttingedges.04, .05, .06, .07Convex triangularShaping/Rotary centricProTaper Gold (2013)ProTaper Next (2013)Triple-fluted, Positive rakeangle with asymmetric radial landsShaping/Rotary centricVariable and progressive tapersalong the instrumentRectangular eccentric10–60Regressive taper17–50Variable taper17-50.04, .06, .07Twisted File/SybronEndo (2008)Shaping/Rotary ing, postmanufacture heat treatmentMicromilling, Premanufacture heattreatment: M-wire10–40.04, .06, .08, .10, .12SM – smallTwisted File Adaptive(2013)Shaping/AdaptiveTriangular25/.04, 25/.06,35/.04Twisted under heat,R-Phase, ElectropolishedML – medium large25/.08, tary centricTriangular, with alternating contactpoints along the instrumentProfile Vortex/DentsplySirona (2009)Shaping/Rotary centricConvex 4 e .0615–50.04, .06.Vortex Blue (2012)SAF/ReDent (2010)Hyflex CM/Coltene(2011)Shaping/ Rotary centricHyflex EDM (2016)Continue46Braz. Oral Res. 2018;32(suppl):e671.5 mm2.0 mmMicromilling,ElectropolishedMicromilling, Premanufacture heattreatment: M-wireMicromilling, pre andpostmanufacture heatreatment:BlueLaser cutting15–40Micromilling, Postmanufacture heattreatment: CM.04, .06, .08ElectrodischargeMachining, postmanufacture heattreatment: CM-EDMDouble fluted Hedström designwith positive rake ange
Gavini G, Santos M, Caldeira CL, Machado MEL, Freire LG, Iglecias EF et al.ContinuationReciproc/VDW (2011)Shaping/Reciprocating“S-shaped”Single File techniqueVariable taperR25 (25/0.08)R40 (40/0.06)R50 (50/0.05)Glide oath/ReciprocatingS-shapedVariable Shaping/Rotary centricConvex triangularReciproc Blue (2016)R-Pilot ian’sChoice (2011)13, 16, 19.0220 - 35.04, .06Micromilling,pre-manufactureheat-treatment: M-wireMicromilling, pre andpostmanufacturehea-treatment: BlueMicromilling, pre andpostmanufacture heatreatment: BlueMicromillingMicromilling, pre andpostmanufacture heatreatment: CMVariable taperWave One/DentsplySirona (2011)Modified convex triangular (apical)Convex triangular (coronal)Small (21/0.06)Primary t: M-wireLarge (40/0.08)Shaping/ReciprocatingVariable taperSmall (20/.07)Wave One Gold (2015)Primary (25/.07)ParalleogramMedium (35/.06)Large (45/.05)Wave One Glider(2017)Proglider/DentsplySirona (2014)ProDesign Logic/Easy(2014)ProDesign Logic GlidePath/Easy (2014)ProDesign R/Easy(2014)Variable taperGlide adrangularShaping/Rotary centricTriangularGlide-path/ RotarycentricQuadrangularShaping/ ReciprocatingDouble Helix.03, .05. 0625-50.01Single FileTriangular Booster TipShaping/Rotary andreciprocating centricS-shapedMicromilling,post-manufacture heattreatment: , premanufacture heattreatment: M-wire25/50Variable regressive .06v.XP-endo Shaper/FKGDentaire (2015)Single file15 – 30.01 - minimum .0425-50.04Micomilling, Shape-setting,Heat-treatmentMicomilling, Shape-setting,Heat-treatmentMicromilling, heattreatment15 - 35Shaping/Rotary Centric.04, .06TriangularX1 Blue/MK life nce Rotary File/MK life (2017)Variable TaperS-curve in the instrument’slongitudinal axisTRUShape/DentsplySirona (2015)Genius/Ultradent(2016)Micromilling, postmanufacture heat treatmentShaping/ReciprocatingSingle file20, 25, 40Micromilling, postmanufacture heat treatment.06Typhoon/Clinician’sChoice (2011)Shaping/Rotary tentricConvex triangular20 - 35.04, .06Micromilling,post-manufacture heattreatment: CM* CM: Controlled-memoryBraz. Oral Res. 2018;32(suppl):e6747
Nickel–titanium instruments in endodontics: a concise review of the state of the artmartensitaBfase parenteAmartensitafase parenteFigure 1. Simplified model of martensitic transformationaccording to Otsuka and Wayman.6SME, nickel-titanium has the best biocompatibilityand corrosion resistance, due to its surface coating oftitanium oxide.6 The superelasticity of NiTi alloys isassociated with substantial recoverable deformation(up to 15%) when subjected to loading and unloadingat an appropriate temperature. In SE, the drivingforce of the transformation is mechanical, whereasin the SME, both thermal and mechanical processesare implicated.10Conventional (untreated) nickeltitanium instrumentsThe first NiTi rotary instruments, still with theISO-standard .02 taper, were introduced in 1992,designed by Dr. John McSpadden. Two years laterDr. Johnson introduced the ProFile .04 and Profile.06 NiTi rotary systems, breaking the longstandingparadigm of manufacturing endodontic instrumentsexclusively with the standard .02 taper. The ProFilesystem instruments had a U-shaped cross-section,with a radial land similar to that of the stainlesssteel instruments of the Canal Master U System,designed by Dr. Steve Senia in 1988. The LightSpeedNiTi rotary system, created by Dr. Steve Senia andDr. William Wildey, has a similar cross-section,48Braz. Oral Res. 2018;32(suppl):e67as does the Greater Taper (GT) system developedby Dr. Steve Buchanan. What distinguishes theLightSpeed system from others is the presence of along, flexible shaft and a single, short cutting length(0.25–2mm) with a non-cutting guide tip, whichallows shaping of the apical region alone withoutthe need for excessive enlargement of the coronaland middle thirds of the canal. In the late 1990s,Dr. John McSpadden introduced the Quantec NiTirotary system, consisting of 10 files of different sizes,diameters, and tapers. The evolution of Quantec wasrepresented by the K3 system, which incorporatedinstruments with significant differences in relationto the other existing systems at the time. The uniquecross-sectional design of this system, with threecutting flutes, a positive rake angle, and asymmetricalradial lands, provides excellent cutting capacity.11A new concept in file design was introduced in2001 with the ProTaper system (Dentsply Sirona, York,PA, USA), which incorporates varying, progressivetapers along the cutting flutes of the same instrument.This feature, combined with a convex triangularcross-section, allows the instruments to work ina specific area of the canal during crown-downpreparation, reducing file contact with the dentinwalls and, consequently, reducing stress on theinstrument.12 In 2006, due to the need for improvementof its characteristics, the cross-section of some ofthe instruments was modified and the system wasexpanded, with the addition of additional apicalpreparation files, giving rise to a new generation of thesystem: the ProTaper Universal. These modificationssought to increase flexibility and, consequently, reduceinstrument fractures.13,14Proposing an instrumentation strategy differentfrom that of most rotary systems, the Mtwo system(VDW, Munich, Germany) has an S-shaped crosssectional design that allows preparation of the entireworking length from the very start, from apex tocrown, with each instrument creating a glide pathfor the next, without unnecessary removal of toothsubstance.15 The cutting edges become closer toeach other at the tip of the instrument, allowing amore delicate cutting action in the apical region andmore efficient cutting in the cervical third, as wellas reducing debris buildup16,17 and decreasing the
Gavini G, Santos M, Caldeira CL, Machado MEL, Freire LG, Iglecias EF et al.screw-in effect.18 Schäfer et al.19 compared the efficacyof shaping simulated curved canals using Mtwo ,K3 , and Race files, and concluded that the Mtwoinstruments prepared curved canals more quickly,respecting their original curvature, but the numberof fractured instruments was greater than with theRace and K3 systems. Recently, Shivashankar et al.20reported similar findings regarding dentin volumeremoved and canal transportation in the preparationof mesial molar canals with the Mtwo, ProTaper, andProtaper NEXT systems.using this technology, remains available worldwidewith several variations and clinical sequences.27,28The Race instruments have a triangular cross-sectionand cutting edges arranged alternately with respectto the axis of the instrument, in the longitudinal andoblique directions. According to the manufacturer,this design reduces the feed speed and the screw-ineffect within the root canal.27 The main objectiveof this system is to achieve a more biological canalpreparation, with larger apical diameters,29 whichhelps the chemical irrigant penetrate further, thuscontributing to greater microbial reduction, withminimal apical transportation.30,31 Busquim et al.32compared preparation with the BioRace sequence versusthe Reciproc system, and concluded that, while thelatter produced greater volumetric gain in the canal,the BioRace system left a smaller area of untoucheddentin walls in the middle and cervical thirds.More recently, a new generation of the Race system– the BT-RaCe instruments – was introduced. Theseinstruments have a special non-cutting “boostertip” (BT) up to 0.17mm in length with six cuttingedges and a reduced diameter, which, accordingto the manufacturer, facilitates progression of theinstrument to the apical region of the root canal whilemaintaining its original curvature. They are availablein a simplified sequence with three instruments:BT-1 (10/.06), BT-2 (35/.00), and BT-3 (35/.04), as wellas two supplemental instruments for when greaterenlargement of apical diameter is required. Bürkleinet al. 33 recommend that the second instrumentof the series (BT-2) should be used in a delicate,smooth pecking motion, because it is less resistantto buckling than an instrument of the same diameterand greater taper, due to its cylindrical design, whichalso makes progression of this instrument moreNiTi alloy treatmentsDespite t he adva nt ages prov ided by t hesuperelasticity of the NiTi alloy, instrument fracture isstill a clinical concern. Possible strategies to increaseefficiency and safety of NiTi rotary files includeimprovements in the manufacturing process or theuse of new alloys that provide superior mechanicalproperties.21,22 The mechanical properties and behaviorof the NiTi alloy vary according to its chemicalcomposition and thermal/mechanical treatmentduring manufacturing.6,23,24 A timeline of thesetreatments is presented in Figure 2.Electropolishing: electrochemical surfacetreatmentElectropolishing (electrochemical surface treatment)was introduced by FKG (La Chaux-de-Fonds,Switzerland) in 1999. After the machining process,instruments receive this surface treatment, whichincreases cutting efficiency while reducing defectsresulting from the manufacturing process, therebyincreasing fatigue resistance.25,26 The Race system(FKG, La Chaux-de-Fonds, Switzerland), nventionalNiTi rolledMemory(CM)CM BlueCM GoldMax-WireCM-EDMElectrodischargeMachiningFigur
Shaping/Rotary centric Triangular with alternating cutting edges along the instrument Micromilling, Electropolishing IRace (2011) 10–60 BioRace (2012) .02, .04, .06 Series ISO 10 (2010) Glide path/Rotary centric Quadrangular 10.02, .04, .06 Scout Race (2014) Glide path/Rotary centric Quadrangular 10, 15,
Kauser, 6Dr. Aman Khan, 1PG Student, Dept. Of Conservative Dentistry & Endodontics, 2Professor and HOD, Dept. Of Conservative Dentistry & Endodontics, 3Reader, Department Of Conservative Dentistry and Endodontics. 4Senior Lecturer, Department Of Conservative Dentistry and Endodontics.
was some improvement. Removal of nickel from the spent electroless nickel bath was 81.81% at 5 A/dm 2 and pH 4.23. Under this condition, the content of nickel was reduced to 0.94 g/L from 5.16 g/L. with 62.97% current efficiency. Keywords: Electroless bath, Nickel, Electrolytic reduction, Nickel Recovery, Current efficiency. Introduction
Titanium Machining Guide cold working and heat effects work-hardened layers Titanium chips tend to adhere to the cutting edges and will be re-cut if not evacuated from edges. Plastic deformation sometimes occurs. continuous long chip formation in aluminum segmental chip formation in titanium Titanium and Titanium Alloys (110-450 HB) ( .
Isopropyl Titanium Triisostearate is safe in cosmetics in the present practices of use and concentration described in the safety assessment, when used as a surface modifier. The data are insufficient to determine the safety of the following 4 ingredients: Titanium Citrate, Titanium Ethoxide, Titanium Isostearates, and Titanium Salicylate.
Titanium alloys commonly used in industry Table 1 1 INTRODUCTION 35A 1 R50250 35,000 psi 25,000 psi C.P. Titanium* 50A 2 R50400 50,000 psi 40,000 psi C.P. Titanium* 65A 3 R50550 65,000 psi 55,000 psi C.P. Titanium* 75A 4 R50700 80,000 psi 70,000 psi C.P. Titanium* 6-4 5 R56400 130,000 psi 120,000 psi 6% AI, 4% V *Commercially Pure (Unalloyed .
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Endodontics, MA Rangoonwala Dental College and Research Centre, Pune, Maharashtra, India Conservative endodontics: A truss access case series Hussain Mookhtiar, Vivek Hegde, Srilatha S and Meheriar Chopra Abstract The prime objective of this case report is to obtain access cavity designs that is strategic dentin preservation (ie, leaving a .
Essential Endodontics, P.A. may accept co-assignment of my benefits where applicable. 3. The amount of insurance coverage . estimated. for treatment at Essential Endodontics, P.A., is based on information I have provided and other information obtained directly from the insurance company, which may result to be inaccurate in part or
