Wave one august newsletter

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Wave one august newsletter

  1. 1. ENDODONTIC SOLUTIONS FALL 2012 E n dodontics Seismic Wave (One™) A progressive shift in technical awareness The history of Endodontics in the on how much of a curve has beenMILESTONES latter part of the twentieth century placed; the bigger the curve, the was hallmarked by two tectonic bigger the envelope (taper), the milestones: the Envelope of Motion smaller the curve, the smaller the1970 Schilder Envelope of Motion principle developed by Dr. Schilder in envelope (taper). the 1970’s (Fig 1) and the Balanced Force theory postulated by Dr. Roane Dr. Roane’s vision recognized that to1980 Roane Balanced Force Technique in the 1980’s (Fig 2). Dr. Schilder routinely and dependably accomplish recognized that the shape of a optimal debridement and1991 Passive radial lands, fixed tapers, prepared canal was directly related to disinfection each time a canal is1 cross-section (4 /18 instruments) the motion of the instrument used to prepared, it seems reasonable to sculpt the space, rather than to any demand the same completeness of particular instrument design or preparation for each canal regardless2001 Active cutting edges changing procedural protocol. Dr. Roane’s of whether it is straight or curved.tapers, 1 cross-section (4 /18 concept of the Balanced Force Variations in the size of preparationsinstruments) Technique is derived from the should occur in response to root or physical law that states that for every canal size rather than the degree of2007 New NiTi metallurgy (science of action there is an equal and opposite root curvature. If such were possible,refining metals) reaction. Cutting/sculpting of the specifically defined standardized inner space of the root canal system canal preparations based on is accomplished using counter intracanal morphological needs and2010 Active file, changing tapers, clockwise rotation and inward not root curvature could be used. Thechanging cross-section & unique pressure adjusted to match the file’s goal of preparation based upon rootmovements (1 instrument) strength; light for small instruments, size rather than curvature manifested heavy for large instruments. as "the balanced force concept” (Fig.kendo@endosolns.com 2) Dr. Schilder recognized that thewww.endosolns.com mainstream step-back approach to ENVELOPE OF MOTION canal instrumentation with a push / pull filing technique augmented by In Dr. Schilder’s process, a precurved circumferential movement was the reamer is passively inserted in the harbinger of ledges, strip canal to a position just prior to perforations, blockages, lack of apical binding. The reamer will then contact patency and a multitude of ancillary in two places — near the tip and at iatrogenic problems. As an the widest part of the bend (the alternative, he developed the belly). If the reamer is positioned Envelope of Motion technique using further down the canal, more lateral K hand reamers. The fluted portion of pressure is developed as the heavy the reamer is curved approximating a curve of the reamer pushes the belly semi-circle. While holding the shaft more forcibly against the canal wall. A vertically, the “envelope” is lesser curve means less lateral generated as the reamer is spun (Fig. pressure, pressure, thus less work by 1). The size of the envelope dependsEVALUATE, RECIPROCATE, REPLICATE, REHABILITATE 1
  2. 2. KENNETH S. SEROTA, DDS, MMSC FALL 2012the belly and less cutting in that area. A push / pull Recapitulation as defined by Dr. Schilder is “the sequentialamplitude of motion is never used. All the work is done on reintroduction of a previously placed series of reamers intothe outstroke, obviating the potential for ledge creation. the root canal space”. The term has often been confused with the idea of recapitulation meaning “repeated patencyPassive placement of a precurved instrument in the canal checks with previously placed files”. Recapitulation is notprevents inadvertent penetration through the apical merely a patency check. Control of the shape being createdforamen as the bend in the reamer makes the instrument act is a function of the number of recapitulations performed.like a spring minimizing the depth of penetration. Thus, Recapitulation moves the belly of the previously placedduring initial instrumentation, the operator is always reaming reamers further down the canal. As such, each recapitulationshort of the apical terminus. The rubber stop is set to this through a series of reamers moves the developing taperlevel, in essence the first of a series of tapers defined by the toward the terminus creating deep shape and ultimatelycanal shape. enhanced density of the obturation.As long as the instrument is not forcefully placed in the canal In theory, the envelope of motion technique “creates” aand the tip is not actively engaged, coronal enlargement or multiple tapered instrument from within a fixed tapered“bodywork’ will occur. Early pre-enlargement of the canal instrument application. Dr. Schilder’s concept is a de factobody enables greater control during the apical third rotary motion approach with a multiple taper construct. Thepreparation. This precept has manifested as coronal shaper/ operator can readily achieve 300 rpm speeds with handenlargement files and has become the “sine qua non” of reaming and yet engender a lesser risk of instrumentmany of the over sixty nickel titanium [NiTi] systems in the breakage. Even if a reamer is over-torqued the clinician willmarketplace. feel the sensation should the instrument engage too much dentin.The instrument is withdrawn using 360 degree rotationalmovement. The rate of withdrawal depends on the curvature FIGURE 1 - Precurving the reamer and rotatingof the canal; the straighter the canal, the deeper the initial and withdrawing the instrument during itsinsertion; in more curved canals, there is less initial working cycle generate the envelope of motion.penetration. Speed of rotation can also be varied. Straighter All the work is done on the outstroke, obviatingcanals can be reamed more quickly, albeit with a slower the potential for ledge creation.withdrawal and more rotations per individual file usage.Curved canals usually require less rotations and a more rapidwithdrawal of the reamer. The essence of the mechanicsengineered into rotary nickel-titanium motors should bepatently clear.Dr. Schilder taught that it was more important to let theinstruments find their own depth. He wanted to emphasizethat each canal had its own taper and that attempting toforce an instrument to go to a predetermined length couldpotentially encourage ledging. This was a radical departurefrom the step-back instrumentation procedure in vogue atthe time.The randomization of work done during withdrawal preventssteps and ledges. It is necessary to recurve the reamer aftereach insertion as the envelope flattens out each time it isused. It is the randomization of the belly, working against thecanal wall that prevents the instrument from going to thesame spot each time. The tip never binds, the only part thatis in active contact is the belly, and thus the tip becomesirrelevant. Patency is verified frequently and copiousirrigation is a required constant. The elimination of rulermeasurements except for the working length determinationestablishes a regimen where the canal itself dictates shapebased upon its diametral size and flow characteristics.EVALUATE, RECIPROCATE, REPLICATE, REHABILITATE 2
  3. 3. KENNETH S. SEROTA, DDS, MMSC FALL 2012Dr. Roane’s “balanced force concept”of instrumentation is simply anexpansion of the concept of reamingcanals. It differs primarily in that thecutting motion is intentionallycounterclockwise and may beaccomplished at any level withoutblockage, especially when modifiedinstruments are used (Roane was avisionary in his recognition of theneed for tips to be configured asnon-cutting). Instrument placement isaccomplished by clockwise rotationand is capable of producingsignificant loads on an instrument tipwithout requiring the application ofinward pressure by the operator. Thisfact enables small instruments (#8and #10 SS files) to be crushed pastcalcifications and allows the clinicianto open calcified canals rapidly. Inaddition, this approach to calcifiedcanals appears to reduce the instrumentation may progress. Upon FIGURE 2 - The reactions occurringincidence of secondary blockage reinsertion, preparation is continued along the blade inclines of a K-typefrom loosened particles. until the desired working depth is file during clockwise and obtained and the canal diameter has counterclockwise rotation areThe balanced force concept is similar been enlarged by counterclockwise shown. Dentin strikes the inclineto reaming in the fact that clockwise rotation of at least 120 degrees. A opposite the rotating force, debrisrotation of each instrument must be greater angle of rotation is desired, is reflected to the dentin side, whilelimited to no more than 180 degrees i.e. one or two revolutions, but a portion of the torque is vectoredin order to prevent over-insertion of cannot be safely accomplished in all causing the instrument to move intothe apical portion of the instrument canals. This is especially true when an the canal when the torque isinto dentin. Such over-insertion extremely sharp curvature exists as clockwise and out of the canal whencauses the tip to cease turning and such a curvature can easily cause the torque is counterclockwise.allows the rotating force to unwind fatigue failure and result in Inward movement is labeled powerthe file coronal to that point and instrument separation. Canals which and is used to place the instrumentincreases the likelihood of instrument are evenly curved throughout their into canals. Outward movement isseparation. Each placement load is length produce little likelihood of labeled control. It is used tofollowed by a cutting motion, fracture while those exhibiting sharp incrementally disengage the cuttingcounterclockwise rotation of 120 curvature concentrated in a small edges and may be opposed by thedegrees or greater. This action segment of the root require careful operator pushing inwardly tocompletely enlarges the canal to the rotation with minimum or limited produce a finite control over thefile diameter, frees the instrument, clockwise / counterclockwise cutting force.and prepares it for placement to a movement, i.e. 120 degrees eitherdeeper depth when the next direction. Enlargement is noticeably ☛ relative to instrument failure duringclockwise rotation is supplied. slower in such situations. clinical use. In that study instrument damage was related to the directionClockwise placement and Sharp curvatures located primarily in of rotation that produced thecounterclockwise cutting rotations the apical one third of a canal present observed faults or failure in order toare repeated until the desired depth the greatest difficulty as they do not determine the risk of instrumentor working length is reached. On allow much alteration of the curvature separation and its relationship to theoccasion the file becomes filled with angle or radius via canal access and direction of rotation. The datadebris and will hesitate to accept the their influence is expressed through a obtained helps to explain ournext placement motion. When that very short lever arm. To support the apparent disregard for reportedoccurs, the file must be removed, balanced force concept and establish counterclockwise instrumentcleaned, and then reinserted before its safety, we have accumulated data ☛EVALUATE, RECIPROCATE, REPLICATE, REHABILITATE 3
  4. 4. KENNETH S. SEROTA, DDS, MMSC FALL 2012http://www.slideshare.net/Endosolns/waveone-video-dentsplyWAVE ONE™ FILE SYSTEM - material reproduced from design, the CCW engaging angle is 5 times the CWarticle by Dr. Cliff Ruddle disengaging angle. There are 3 critical distinctions with this novel, unequal bidirectional movement. One, compared toThe 3 WaveOne instruments are termed small (yellow continuous rotation, there is a significant improvement in21/06), primary (red 25/08), and large (black 40/08). The safety, as the CCW engaging angle has been designed tosmall 21/06 file has a fixed taper of 6% over its active be smaller than the elastic metallurgical limit of the file.portion. The primary 25/08 and the large 40/08 WaveOne Two, opposed to all other reciprocating systems that utilizefiles have fixed tapers of 8% from D1 to D3, whereas from equal bi-directional angles, the WaveOne system utilizes anD4 to D16, they have a unique progressively decreasing engaging angle that is 5 times the disengaging angle.percentage tapered design. This design serves to improve Fortuitously, after 3 engaging/disengaging cutting cycles,flexibility and conserve remaining dentin in the coronal two the WaveOne file will have rotated 360°, or turned onethirds of the finished preparation.  CCW circle. This unique reciprocating movement enables the file to more readily advance toward the desired workingAnother unique design feature of the WaveOne files is they length. Three, compared to an equal bi-directionalhave a reverse helix and 2 distinct cross-sections along the movement, an unequal bi-directional movementlength of their active portions (Fig. 3). From D1 to D8, the strategically enhances augering debris out of the canal.WaveOne files have a modified convex triangular cross Auguring debris in a coronal direction promotes thesection, whereas from D9 to D16, these files have a convex biological objectives for preparing canals, 3-D disinfection,triangular cross section. The design of the 2 WaveOne cross and filling root canal systems.sections is further enhanced by a changing pitch and helicalangle along their active portions. The WaveOne files have FILE SELECTIONnon-cutting modified guiding tips, which enable these filesto safely progress through virtually any secured canal. Although there are 3 WaveOne files, the primary 25/08 fileTogether, these design features enhance safety and is invariably used first in any canal that has a confirmed,efficiency when shaping canals that have a confirmed, smooth, and reproducible glide path equivalent to at leastsmooth, and reproducible glide path. The files are a loose No. 10 file. However, in longer, narrower, and moremanufactured with M-wire technology which significantly curved canals, even when the 10 file is loose at length, theimproves the resistance to cyclic fatigue by almost 400% primary 25/08 WaveOne file will more predictably advancecompared to commercially available 25/04 Ni-Ti files. to the terminus of the canal when the glide path is expanded.RECIPROCATION MOVEMENT The small 21/06 WaveOne file is used when the primaryThis motor produces a feature-specific, unequal bi- 25/08 WaveOne file will not progress apically through adirectional file movement. Because of the reverse helix smooth reproducible glide path. The 21/06 is designed toEVALUATE, RECIPROCATE, REPLICATE, REHABILITATE 4
  5. 5. KENNETH S. SEROTA, DDS, MMSC FALL 2012through a smooth reproducible glide mentioned, infrequently but on 10 file cannot be initially and safelypath. The 21/06 is designed to work occasion, the clinician may require a worked to length. In these instances,in smaller diameter, longer length, or second WaveOne file to complete a there is generally no need to selectmore apically curved canals. In certain predictably successful final shape. and use size 06 and/or 08 hand filescanals, when this file reaches the in an effort to immediately reach theworking length, the clinician may SHAPING TECHNIQUE terminus of the canal. Simply workdeem the preparation completed or, the size 10 hand file, within anyalternatively, may desire more deep As is required for any shaping region of the canal, until it isshape. In these instances, the small technique, straight line access to completely loose . The advantages of21/06 is considered a "bridge file" each orifice is emphasized. The a sequential glide path have beenbecause it promotes safety when orifice(s) should be pre-enlarged and previously elucidated.transitioning back to the 25/08 all internal triangles of dentinWaveOne file. Even in these eliminated. Perhaps the greatest When GPM procedures have beeninstances, the WaveOne technique is challenge performing endodontic completed, the access cavity isstill a safe and efficient 2-file treatment is to find, follow, and voluminously flushed with a 6%sequence compared to virtually all predictably secure any given canal to solution of sodium hypochlorite.other mechanical shaping systems. its terminus. Negotiating and Shaping can commence, starting with securing canals with small-sized hand the primary 25/08 WaveOne file .The large 40/08 WaveOne file is used files requires a skillful touch, patience, Gentle apically directed pressure willto complete the shape in larger and desire. Securing a canal is an art typically allow this instrument to run 2diameter canals that are typically and a critically essential element to 4 mm inward. After every fewstraighter. Examples include certain influencing predictably successful millimeters of advancement, or if themaxillary incisors, single-canal endodontic outcomes. At the end of primary 25/08 WaveOne file will notbicuspids, and larger diameter canals the day, a small-sized hand file is easily progress, remove this file andwithin maxillary and mandibular used to either confirm existing space clean and inspect its flutes. Uponmolar teeth. Recall, the usual is available or, alternatively, to create removing any mechanical shaping fileWaveOne protocol is to initiate sufficient space so mechanical files from any canal, it is wise to irrigate,shaping procedures using the primary can safely follow a secured canal. To recapitulate with a 10 file, then re-25/08 file. However, after carrying the clarify, a canal is secured when it has irrigate. Strategically, recapitulatingprimary 25/08 file to the working a confirmed, smooth, and with the 10 file moves debris intolength, gauging procedures may reproducible glide path. solution, confirms the glide path, andconfirm that the foramen is bigger provides confidence that shapingthan 0.25 mm. In these instances, the With an estimated working length procedures can continue with theclinician will require the 40/08 and in the presence of a viscous same 25/08 WaveOne file. Typically,WaveOne file to fully shape and finish chelator, insert a 10 file into the the primary WaveOne file will runthese larger canal systems. With orifice and determine if the file will inward, progressively advance, andexperience, the clinician will learn to easily move toward the terminus of incrementally move through anyrecognize these larger and more the canal. In shorter, wider, and region of the canal that has astraightforward canals and is straighter canals, a 10 file can usually confirmed and reproducible glideencouraged to initiate canal be readily carried to the desired path.preparation procedures utilizing only working length. A loose 10 filethe 40/08 WaveOne file. confirms sufficient existing space is A brushing motion may be utilized to available to immediately initiate eliminate interferences, remove mechanical shaping procedures internal triangles of dentin, or toIn summary, there are 3 WaveOne utilizing the primary 25/08 WaveOne enhance shaping results in canalsfiles. Following access and GPM file.  which exhibit an irregular crossprocedures, the primary 25/08 section. In one or more passes,WaveOne file will generally progress However, in longer, narrower, and continue with the primary 25/08 fileto the desired working length in 3 or more curved canals, often times the through the body of the canal.more passes. As previously EVALUATE, RECIPROCATE, REPLICATE, REHABILITATE 5
  6. 6. KENNETH S. SEROTA, DDS, MMSC FALL 2012 Fig 3. The instruments are designed to work with a reverse cutting action. All instruments have a modified convex triangular cross-section at the tip end and a convex triangular cross-section at the coronal end.Removing canyons of restrictive dentin from the coronal dentin. Alternatively, the size of the foramen can be gaugedtwo thirds of a canal creates a more direct path to its apical with a size 25/02 hand file. When the size 25 hand file isone third, improving accuracy when determining a precise snug at length, the shape is done. If the size 25/02 hand fileworking length.  is loose at length, it simply means the foramen is larger than 0.25 mm. In this instance, gauge the foramen with aEspecially in longer, narrower, and more curved canals, the size 30/02 hand file. If the size 30 hand file is snug at length,apical one-third of virtually any canal can be more the shape is done. If the size 30 hand file is loose at length,predictably secured when pre-enlargement procedures proceed to the large 40/08 WaveOne file to more optimallyhave been performed first. A pre-enlarged canal improves prepare and finish these larger canals.the ability to more readily direct and slide a precurvedsmall-sized hand file to the full working length. Upon reaching the working length, remove the 40/08 WaveOne file and inspect its apical cutting flutes. If theRegardless of the glide path sequence, once the apical one flutes are loaded with dentine mud, there is visualthird has been fully negotiated, establish working length, confirmation that this file has cut its shape in the apical oneconfirm patency, and verify there is a smooth, reproducible third. Alternatively, the terminal size of the preparation canglide path. The glide path is secured when a 10 file is loose be gauged using a size 40/02 hand file. When the size 40/02at length. hand file is snug at length, the shape is done and the foramen is confirmed to be 0.40 mm. When the 40/02 handWhen the canal is secured, the primary 25/08 WaveOne file file is loose at length, it simply means the foramen is largercan generally be carried to the full working length in one or than 0.40 mm. In these instances, other methods may bemore passes. When this primary file will not readily advance utilized to finish these larger, typically less curved, and morein a secured canal, then the small 21/06 WaveOne file may straightforward canals.be utilized. This file will typically reach the desired workinglength in one or more passes. The small 21/06 file may be There are differing opinions regarding the optimal size andthe only shaping file taken to the full working length, taper to prepare the apical one-third of any given canal.especially in more apically or abruptly curved canals. Importantly, clinicians should not be trying to mechanicallyHowever, with the anatomy in mind, to encourage 3-D prepare "round" foramena; rather, clinicians should bedisinfection and filling root canal systems, more shape may trying to "clean" foramena. Cleaning is readilybe indicated. In these instances, the 25/08 file will generally accomplished in a preparation that has a sufficientlyadvance through any region of a canal where the shape has tapered resistance form. Well-shaped canals promote thebeen previously expanded utilizing the small 21/06 bridge exchange of irrigants into all aspects of the root canalfile. system. Debridement and disinfection are the keys to endodontic success; shape is simply the design parametersOnce the primary 25/08 WaveOne file readily moves to the that achieve the optimal biologic ends.working length, it is removed. The finished shape isconfirmed when the apical flutes of this file are loaded withEVALUATE, RECIPROCATE, REPLICATE, REHABILITATE 6

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