Broken Instrument Removal:The Endodontic Challenge*

By

Dr. Clifford J. Ruddle

*Originally published in Dentistry Today, July 2002

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Every clinician who has performedendodontics has experienced a variety ofemotions ranging from the thrill-of-the-fill to an upset like the procedural acci-

dent of breaking an instrument. During root canalpreparation procedures, the potential for instrumentbreakage is always present. When instrumentbreakage occurs, it immediately provokes despair,anxiety, and then the hope that nonsurgical retreat-ment techniques exist to liberate the instrumentfrom the canal.

Many clinicians associate “broken instruments”with separated files, but the term could also apply toa sectioned silver point, a segment of a lentulo, agates glidden drill, a portion of a carrier-based obtu-rator, or any other dental material left inside thecanal.1,2 With the advent of rotary NiTi files, therehas been an unfortunate increase in the occurrenceof broken instruments and the factors contributingto breakage have been identified.3 The conse-quences of leaving, versus removing broken instru-ments from the canal have been discussed in the lit-erature and a variety of approaches for managingthese obstructions have been presented.4-6

Today, separated instruments can usually beremoved due to technological advancements invision, ultrasonic instrumentation, and microtubedelivery methods. Specifically, the dental operatingmicroscope allows clinicians to visualize most bro-ken instruments and fulfills the age old adage, “Ifyou can see it, you can probably do it”. In combi-nation, the microscope and ultrasonic instrumenta-tion have driven “microsonic” techniques whichhave dramatically improved the potential and safe-ty when removing broken instruments.7-9

Factors Influencing BrokenInstrument Removal

The factors influencing broken instrumentremoval should be identified and fully appreciated.The ability to nonsurgically access and remove abroken instrument will be influenced by the diame-ter, length and position of the obstruction within acanal. The potential to safely remove a brokeninstrument is further guided by anatomy, includingthe diameter, length, and curvature of the canal, andadditionally limited by root morphology, includingthe thickness of dentin and the depth of externalconcavities. In general, if one-third of the overalllength of an obstruction can be exposed, it can usu-ally be removed. Instruments that lie in the straight-away portions of the canal can typically beremoved. Separated instruments that lie partially

around canal curvatures, althoughmore difficult, can oftentimes beremoved if straightline access can beestablished to their most coronalextents. If the broken instrument seg-ment is apical to the curvature of thecanal and safe access cannot be accom-plished, then removal is usually notpossible and, in the presence of signsor symptoms, surgery or an extractionwill at times be required.

The type of material comprising anobstruction is another important factorto be considered. As an example,stainless steel files tend to be easier toremove as they do not further fractureduring the removal process. Nickel-titanium broken instruments maybreak again, albeit deeper within thecanal, during ultrasonic efforts due toheat buildup. Whether a separatedfile’s cutting action was clockwiseversus counterclockwise is importantto visualize and know as this factorwill influence the correct ultrasonicremoval technique.

Another factor that is central to suc-cessful instrument removal is integrat-ing the best presently developed andproven technologies. Traditionally,retrieving broken instruments posedformidable challenges. One time-hon-ored technique has been the use ofsmall files in efforts to either remove,or at least bypass, the broken instru-ment. Over time, retrieval techniquesevolved but were oftentimes ineffec-tive because of limited vision and/orrestricted space. Frequently, effortsdirected toward instrument retrieval,even when successful, weakened a rootdue to overzealous canal enlargement,which in turn predisposed to a hopelessfracture and the loss of a tooth. Indeed,the prognosis of a tooth can be serious-ly compromised if the efforts to removea broken instrument lead to iatrogenicevents, such as a ledged canal or rootperforation. When retrieval efforts areunsuccessful, cleaning, shaping andobturation procedures are compro-mised and the ultimate prognosis is indoubt. Today, most broken instruments

can be safely and efficiently removedwith the use of advanced technologiesand proper training.

Armamentarium for BrokenInstrument Removal

Highspeed rotary cutting tools areselected to create and refine straight-line coronal access into the pulpchamber. Cost effective and highlyefficient, surgical length tapered dia-monds can be used, with or withoutwater, to flare the axial walls and fin-ish all aspects of the access prepara-tion. Diamond coated burs are avail-able in different lengths, diameters,tapers and abrasively coated grits.Access refinements can be made safe-ly and with precision when a surgicallength tapered diamond is rotated atslow RPM. Precision and safety arefurther improved when the distal endof the diamond is used with a lightbrushing motion to carefully sandaway material. As such, based on thespecific procedural task, a tapered dia-mond can be chosen whose distal endhas a thin and pointed, rounded, orball-type configuration. Commonsense should prevail when choosingrotary cutting burs versus ultrasonicinstruments for finishing the accesscavity. In the author’s opinion, ultra-sonic access refinement tips are need-less, inefficient and approximately six(6) times more costly compared torotary cutting instruments whichaccomplish the same task.

The preferred armamentarium forbroken instrument removal is:

Gates Glidden Drills. Gates Glidden(GG) drills (Dentsply Maillefer; Tulsa,Oklahoma) sizes 1 to 6 have maxi-mum diameters of 0.5, 0.7, 0.9, 1.1,1.3 and 1.5 mm, respectively, and areused to create radicular access and auniform tapering funnel to theobstruction.

Piezoelectric Ultrasonics. In theauthor’s opinion, the Satelec P5(Dentsply Tulsa Dental; Tulsa,Oklahoma) is the piezoelectric ultra-sonic unit of choice for performing

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endodontic treatment and retreatmentprocedures (Figure 1). This unitaffords precise working accuracy andhas a broad power range, and its unique“feedback” system measures tip resist-ance, regulates tip movement andreduces the potential for tip breakage.

ProUltra® ENDO-3, 4, 5 Tips. TheProUltra ENDO tips (Dentsply TulsaDental; Tulsa, Oklahoma) afford a clin-ical breakthrough in nonsurgical ultra-sonic instrumentation as their contra-angled and parallel walls improvevision when working below the orifice.Additionally, the ENDO-3, 4 and 5 arestainless steel instruments coated withzirconium nitride to improve durabilityand cutting efficiency (Figure 2a).Importantly, zirconium nitride resistscorrosion, regardless of the irrigant

employed, does not flake-off duringuse, and provides safe efficiency whenperforming delicate and precise intra-canal procedures, as compared to moreaggressive diamond coatings. TheProUltra instruments are used on thelower power settings and have beendesigned to intentionally work dry.

ProUltra ENDO-6, 7, 8 Tips. TheENDO-6, 7 and 8 ultrasonic instru-ments are made of titanium to provideclinicians with thinner diameters andlonger lengths as compared to theENDO-3, 4 and 5 (Figure 2b). Theseinstruments are utilized on the lowerpower settings, work dry, and areemployed to perform procedures indeeper spaces where access is morerestrictive.

Stropko. The Stropko three-wayadapter (Vista Dental; Racine,Wisconsin) is used for collimating anddirecting air into the operating field.The Stropko blows out dentinal dustduring ultrasonic use and providesconstant vision. This adapter’s proxi-mal end is placed into the three-waysyringe and its distal end has luer-lockthreads for securely attaching differentlength and gauged canuli.

Instrument Removal System (iRS™).The iRS (Dentsply Tulsa Dental;Tulsa, Oklahoma) is a new two-com-ponent system designed to mechani-cally engage broken instruments(Figure 3). Each microtube has asmall-sized plastic handle to enhancevision during placement, a side win-dow to improve mechanics, and a 45°beveled end to “scoop up” the coronalend of a broken instrument. Eachscrew wedge has a knurled metal han-

dle, a left handed screw mechanism, and a solidcylinder that becomes tapered towards its distal endto facilitate engaging an obstruction.

Post Removal System (PRS). The PRS kit(SybronEndo; Orange, California) contains severalcomponent parts that may be utilized to mechanical-ly form threads and engage any obstruction whosediameter is 0.6 mm or greater (Figure 4).Specifically, the #1 and #2 taps will oftentimes grasp

intracanal obstructions that extend into the pulpchamber, such as a silver point or carrier-based obtu-rator.

Magnification & Lighting. Magnification glass-es, headlamps, fiberoptic transilluminating devicesand dental operating microscopes contribute to bet-ter vision. Specifically, the microscope providesoptions in magnification and coaxial light to pro-mote superior vision. The microscope is a practice-building instrument that promotes professionalgrowth, improves technical results and distinguish-es a practice in its community.

Techniques for Broken Instrument Removal

Prior to commencing retrieval efforts, specialattention is directed towards pre-operative radi-ographs and working films to better appreciate thethickness of the dentinal walls and, if present, thedepth of an external concavity. Coronal access isthe first step in the removal of broken instruments.Highspeed, friction grip, surgical length burs areselected to create straightline access to all canal ori-fices. Special attention should be directed towardsflaring the axial wall that approximates the canalholding the broken instrument in efforts to subse-quently improve microsonic techniques below theorifice. The most important techniques for brokeninstrument removal have been clearly illustratedand clinically shown in the “Ruddle onRetreatment” video series.10

With safety in mind, radicular access is the sec-ond step required in the successful removal of a

Figure 1. The Satelec P5 piezoelectric ultra-sonic unit has a wide incremental power rangeand provides controlled linear tip movement toenhance clinical performance.

Figure 2a. The ProUltra ENDO-3, 4 and 5ultrasonic instruments’ parallel walls and zir-conium nitride coatings improve access, visionand clinical efficiency.

Figure 2b. The ProUltra ENDO-6, 7 and 8are titanium ultrasonic instruments havelonger lengths and smaller diameters to facilitate deeper “microsonic” techniques.

Figure 3. The iRS is a device for engagingand removing broken instruments. Each iRS is comprised of a different gauge microtube andscrew wedge.

Figure 4. The PRS kit is comprised of 5 variously-sized trephines and corresponding taps,a transmetal bur, rubber bumpers, a torque barand the extracting pliers.

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broken instrument. If radicularaccess is limited, hand files areused serially small to large,coronal to the obstruction, tocreate sufficient space to safelyintroduce GG drills. GG’s arerotated at speeds rangingbetween 800-900 rpm and,importantly, are used like“brushes” to create additionalspace and maximize visibilitycoronal to the obstruction.Increasingly larger GG’s areuniformly stepped out of thecanal to create a smooth flow-ing funnel which is largest atthe orifice and narrowest at theobstruction. GG drills shouldbe limited to the straightawayportions of the canal with noeffort made to carry themaround the curve in the eventthe instrument lies apical to thecurvature. A GG-1 (0.50 mm)or GG-2 (0.70 mm) can usuallybe carried to the depth of theseparated instrument. TheGG’s are used cautiously inapproximation to the obstruc-tion with attention tobrush-cutting out of thecanal and away fromfurcal danger.Relocating the coronalone-third of a canalaway from the furcationreduces the potential forroot thinning, or a stripperforation, andimproves straightlineradicular access. The GG-3(0.90 mm) is carried short ofthe level where the GG-2 wasused and, in furcated teeth, theGG-4 (1.10 mm) is confined toa depth of no more than onebud length below the orifice.Importantly, radicular accessshould be performed so that thecanal is pre-enlarged and ideal-ly shaped “no bigger” than itwould otherwise be prepared ifthere was no broken instrumentobstructing the canal.

When the canal has beenoptimally shaped, thenmicrosonic techniques may beemployed to remove a brokenfile segment. At times, when anultrasonic instrument is intro-duced into a pre-enlargedcanal, its activated tip does nothave enough space, lateral tothe broken file segment, to ini-tiate trephining procedures. Assuch, if greater access isrequired lateral to the mostcoronal aspect of the obstruc-tion, the bud of a GG can be“modified” and then used tocreate a circumferential “stag-ing platform”.8,9 The stagingplatform is made by selecting aGG drill whose maximumcross-sectional diameter isslightly larger than the visual-ized instrument. The bud of theGG drill is altered by cutting itperpendicular to its long axis atits maximum cross-sectionaldiameter (Figure 5). The mod-ified GG drill is gently carriedinto the pre-enlarged canal,

rotated at a reduced speed of300 RPM, and directed apical-ly until it lightly contacts themost coronal aspect of theobstruction. This clinical stepcreates a small staging plat-form which facilitates theintroduction of an ultrasonicinstrument. When properly per-formed, straightline coronaland radicular access, in con-junction with magnificationand lighting, should enable theclinician to fully visualize the

coronal most aspect of a brokeninstrument. To facilitate excel-lent vision to the intra-radicularobstruction, the canal should bevigorously flushed and thor-oughly dried prior to beginningultrasonic procedures.

Ultrasonic TechniquesPrior to performing any

radicular removal techniques, itis wise to place cotton pelletsover other exposed orifices, ifpresent, to prevent the nuisancere-entry of the fragment intoanother canal system. Anappropriately sized ProUltraENDO instrument is thenselected, such that its lengthwill reach the broken obstruc-tion and its diameter willpassively fit into the pre-viously shaped canal.The tip of this ultrasoni-cally selected instrumentis placed in intimate con-tact against the obstruc-tion and typically acti-vated within the lowerpower settings (Figure6a). The clinician shouldalways work at the low-est power setting thatwill efficiently and safe-ly accomplish the clini-cal task. ALL ultrasonicwork below the orifice isconducted DRY so theclinician has constantvisualization of the ener-gized tip and the brokeninstrument. To maintainvision, the dental assis-tant utilizes the Stropkothree-way adapter withthe appropriate luer-locktip to collimate anddirect a continuousstream of air and blowout dentinal dust.

Recently, certain non-surgical instrumentshave become availablewith water port technol-

ogy. Although claims havebeen made that water port tech-nology increases the life ofthese tips, there have neverbeen any scientific or clinicalstudies to support these asser-tions. In the author’s opinion,water port technology in non-surgical ultrasonic instrumentsis contraindicated for fourimportant reasons: One, waterflowing through an ultrasonicinstrument dampens movementand decreases tip performance.Two, small diameter ultrasonicinstruments are weakened andmore predisposed to expensivebreakage when they aremachined for internal waterflow. Three, there is an undesir-

Figure 5. A photograph shows selected GGdrills and their subsequent modification.

Figure 6a. A graphic shows how a stagingplatform can facilitate the strategic placementof an ultrasonic instrument lateral and againstthe separated file.

Figure 6b. A graphic shows an abrasively coat-ed ultrasonic instrument trephining and pro-gressively sanding away dentin to expose thehead of a broken file.

Figure 6c. A graphic demonstrates using alonger length and smaller diameter titaniumENDO-6 ultrasonic instrument when space ismore restrictive.

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able aerosol effect regardless ofwhere the water port is posi-tioned on an ultrasonic instru-ment. Four, and most impor-tant, no water should be usedduring nonsurgical ultrasonicprocedures as moisture, incombination with dentinaldust, creates mud, lost visionand the potential for iatrogenicoutcomes. In summary, clinicalexperience supports the vastmajority of all nonsurgicalultrasonic procedures shouldbe performed DRY, at the low-est power setting that will safe-ly accomplish the clinical task,and utilizing a light brush-cut-ting action. Microsonic tech-niques, as advocated forremoving broken instruments,do not generate sufficient heatto become harmful to theattachment apparatus.However, if ultrasonic proce-dures are performed at higherenergy levels, for longer peri-ods of time, and against larger,conductive objects, such as ametal post, then the dentalassistant should simply use atriplex syringe with an inter-mittent water spray to reduceheat build-up and transfer.Fortunately, heat does not con-duct well through dentin and isfurther rapidly dissipated dueto the moisture content in theattachment apparatus.

The selected ProUltra ENDOinstrument is moved lightly in acounterclockwise (CCW)direction around the obstruc-tion, except when removing afile that has a left-handedthread in which case the direc-tion would be clockwise (CW).This ultrasonic actiontrephines, sands away dentinand exposes the coronal fewmillimeters of the obstruction(Figure 6b). Typically, duringultrasonic use, the obstructionbegins to loosen, unwind and

then spin. Gently wedg-ing the energized tipbetween the tapered fileand the canal wall often-times causes the brokeninstrument to abruptly“jump out” of the canal.In the instance where abroken file lies deep andultrasonic procedures arerestricted by root bulkand form, then select alonger length and smallerdiameter, abrasivelycoated, ultrasonic instru-ment to promote saferetrieval efforts. Inlonger roots, or whenspace is even morerestrictive, then anappropriately sizedProUltra titanium instru-ment may be chosen. TheProUltra titanium instru-ments have longerlengths and smallerdiameters, compared tothe abrasively coatedinstruments, and theirsmooth cutting actionpromotes safety whentrephining deeper withina canal (Figure 6c).Exposing 2-3 mm of thecoronal most aspect of anobstruction, or aboutone-third of its overalllength, will generallyproduce the desiredresult. The clinical stepsfor broken instrumentremoval utilizingmicrosonics are shown inFigures 7a, 7b, 7c and 7d.

On occasion, the clini-cian may create excellent coro-nal and radicular access, identi-fy and expose the separatedinstrument, perform ultrasonictrephining procedures, and stillbe unable to loosen and “jetti-son” the instrument out of thecanal. Further, it may be unsafeto continue trephining around a

broken instrument due to lackof vision or anatomical restric-tions. In these instances, and asa last ultrasonic resort, the han-dle from a stainless steel handfile can be intentionallyremoved and the shaft of theinstrument inserted into adevice called the File Adapter

(SybronEndo; Orange,California). The File Adapterthreads onto the ultrasonichandpiece and its chuck willretain a 0.02 tapered hand file.Although tedious, small stain-less steel hand files can be pre-curved as indicated, insertedinto available space and used atlow power in an ultrasoniceffort to remove a brokeninstrument. This technique is attimes useful when the root isthin and/or the canal is curved.When 2-3 mm of a brokeninstrument has been exposedand if ultrasonic proceduresprove unsuccessful, then analternative removal method isto utilize a microtube device tomechanically engage andpotentially remove the obstruc-tion. For a variety of reasons,the author prefers a mechanicalmicrotube device as comparedto the more traditional “tubeand glue” approaches.

Mechanical MicrotubeOptions

Microtube Tap & ThreadThe Post Removal System

(PRS) contains certain micro-tubular taps which allow theclinician to form threads andmechanically engage the mostcoronal aspect of any obstruc-tion whose diameter is 0.6 mmor greater. These microtubulartaps contain a reverse threadand engage an obstruction byturning in a counterclockwise(CCW) motion. The outsidediameter of the smallest micro-tubular tap generally limits itsuse to the coronal one-third oflarger canals; however, thesemicrotubes can tap, formthreads, and engage a variety ofradicular obstructions thatextend coronally into the pulpchamber. Caution should beused to not over-thread an

Figure 7a. An endodontically failingmandibular first molar. Note a short screwpost, a separated instrument and amalgamdebris from the hemisection procedures.

Figure 7b. A photograph shows the splintremoved, the post out, and an ultrasonicinstrument trephining around the broken file.

Figure 7d. An 8-year recall film demonstrates a new bridge and excellentperiradicular healing.

Figure 7c. A post-treatment radiographreveals three-dimensional retreatment. Notethe third mesial system between the MB andML canals.

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obstruction, like a silver point,so it does not bottom-out andshear off inside the lumen ofthe tap. Once the obstruction issecurely engaged by the micro-tubular tap, the extracting plieris utilized with a protectivebumper to cushion the removalforce.

Tube Mechanics Another technique advocated

to remove broken instrumentsutilizes a microtube and a hed-stroem file. With limitations,this method of removalinvolved sizing and gauging thecorrect microtube so it couldreach and be placed over theultrasonically exposed obstruc-tion. Microtube sizes that wereclinically relevant were 18, 20and 22 gauge (Spinal TapNeedle, Ranfac; Avon,Massachusetts). Because oftheir unique ability to engage, a35, 40 or 45 hedstroem wasselected and, when possible,inserted into the coronal mostaspect of the microtube. Thehedstroem was then passeddown the length of the tubeuntil it was engaged tightlybetween the obstruction andthe internal lumen of themicrotube. Although limited byspace, this removal methodcould, at times, successfullyretrieve obstructions from larg-er canals. Presently, an innova-tive mechanical device, knownas the Instrument RemovalSystem (iRS), has been devel-oped for the retrieval of brokeninstruments in more restrictivespaces.

The InstrumentRemoval System

The Instrument RemovalSystem (iRS) provides a proce-dural breakthrough for theremoval of intracanal obstruc-tions such as silver points, car-

rier-based obturators orbroken file segments.The iRS is indicatedwhen ultrasonic effortsprove to be unsuccessfuland may be used toremove broken instru-ments that are lodged inthe straightaway portionsof the root or partiallyaround the canal curva-ture.9,10 The instrumentwith the black handle is19 gauge (1.00 mm) andis designed to work inthe coronal one-third oflarger canals, whereasthe instrument with thered handle is 21 gauge(0.80 mm) allowing it tobe placed deeper intomore narrow canals.Each complete instru-ment is comprised of acolor coordinated micro-tube and screw wedge.

As has been empha-sized for any removaltechnique and is essentialfor the success of theiRS, straightline coronaland radicular access isrequired to expose andsubsequently visualizethe coronal-most end ofthe broken instrument.As previously described,the clinician utilizesultrasonic instrumenta-tion to circumferentiallyexpose 2-3 mm of theseparated file. However,ultrasonic instrumentscan only circumferential-ly trephine, sand awaydentin, and expose theportion of the obstructionthat lies in the straight-away portion of thecanal. Therefore, the goal is toexpose 2-3 mm, or about one-third of the total length, of aseparated instrument.

A black or red handled

microtube is then selected thatcan passively slide through thepre-enlarged canal and dropover the exposed broken instru-ment (Figure 8a). In a curved

canal, it is axiomatic that thehead of a broken NiTi file willalways lie against the outerwall. In these instances, themicrotube is inserted into thecanal with the long part of itsbeveled end oriented to theouter wall of the canal to“scoop up” the head of the bro-ken instrument and guide itinto the microtube (Figure 8b).Once the microtube has beenpositioned, the same colorcoded screw wedge is insertedand slid internally through themicrotube’s length until it con-tacts the obstruction. Theobstruction is engaged by gen-tly turning the screw wedgehandle counterclockwise(CCW). A few degrees of rota-tion will serve to tighten,wedge, and oftentimes, dis-place the head of the obstruc-tion through the microtubewindow (Figure 8c). If a screwwedge with a specificallymarked color is unable toachieve a strong hold on theobstruction, then the othergauge and color coded screwwedge should be selected toencourage engagement andremoval. When engaged, theobstruction is removed byrotating the microtube andscrew wedge assembly out ofthe canal. The direction of rota-tion, in the instance of a brokenfile, is generally counterclock-wise, but ultimately should beappropriate to the thread designof the obstruction (Figure 8d).If difficulty is encounteredwhen rotating the microtubeand screw wedge assemblyCCW, then proceed with a lim-ited clockwise (CW) rotationof 3-5°, which will promotestaying engaged, followed byturning the assembly CCWuntil snug. This repeated recip-rocating handle motion willserve to loosen and facilitate

Figure 8a. This 21 gauge iRS is a two component device comprised of a microtubeand screw wedge for mechanically removingbroken instruments.

Figure 8b. This graphic illustrates thebeveled end of the microtube oriented towardthe outer wall of the canal to “scoop up” thehead of the broken file.

Figure 8c. This graphic shows the introduc-tion of the screw wedge which is rotated CCWto engage and displace the head of the file outthe side window.

Figure 8d. This graphic demonstratesthe mechanical advantage of utilizingthe iRS to liberate the broken instrumentfrom the canal.

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the removal process. Placingan activated ProUltra ENDO-1tip on the engaged assembly isanother potent adjunct that willpromote removal success. If amicrotube cannot be placedover a broken instrument suchthat the head of the obstructionlies within the side window,then in these instances, themicrotube’s beveled end canbe easily reduced or eliminatedto achieve better mechanics. A

clinical case utilizing the iRSoption is shown in Figures 9a,9b and 9c.

ConclusionThe best antidote for a bro-

ken file is prevention.Adhering to proven concepts,integrating best strategies andutilizing safe techniques dur-ing root canal preparation pro-cedures will virtually elimi-nate the broken instrumentprocedural accident.11,12

Prevention may also be greatlyfacilitated by thinking of nego-tiating and shaping instru-ments as disposable items.Simply discarding all instru-ments after the completion ofeach endodontic case willreduce breakage, lost clinicaltime and upsets. However, onoccasion, an instrument willbreak and in spite of the bestexisting technologies and tech-niques, the broken file segmentmay not be able to beretrieved. In these instances,and in the presence of clinicalsymptoms and/or radiographicpathology, surgery or extrac-tion may be the best treatmentoption.

Dr. Ruddle is founder and director of AdvancedEndodontics, an international educational source inSanta Barbara, California. He is an Assistant Professorof Graduate Endodontics at Loma Linda University andis an Adjunct Professor of Endodontics at University ofthe Pacific, School of Dentistry, in San Francisco. Dr.Ruddle is the author of two (2) chapters in the new 8thEdition of Pathways of the Pulp: “Cleaning & Shapingthe Root Canal System” and “Nonsurgical EndodonticRetreatment”. He is internationally known for provid-ing superb endodontic education as a lecturer andthrough his clinical articles, training manuals, and mul-timedia products. In addition, Dr. Ruddle has recentlycompleted a new CLEAN•SHAPE•PACK video. He can bereached at (800) 753-3636 or www.endoruddle.com.

Clifford J. Ruddle, DDS, FICD, FACD

Disclosure: Dr. Ruddle consults for DENTSPLY and designed theProUltra Endo ultrasonic instruments, previously known as CPR.

References1. Fors UG, Berg JO: Endodontic treatment

of root canals obstructed by foreignobjects, Int Endodont J 19:2, 1986.

2. Chenail BL, Teplitsky PE: Orthogradeultrasonic retrieval of root canalobstructions, J Endod 13: 186-190,1987.

3. Ruddle CJ: Finishing the apical one-third: endodontic considerations,Dentistry Today 21:5, pp. 66-73, 2002.

4. Nagai O, Tani N, Kayaba Y, Kodama S,Osada T: Ultrasonic removal of brokeninstruments in root canals, IntEndodont J 19:298, 1986.

5. Hulsmann M: Removal of fracturedinstruments using a combined auto-mated/ultrasonic technique, J Endod20:3, 1994.

6. Masserann J: The extraction of instru-ments broken in the radicular canal: Anew technique, Acta Odont Stomatol47:265-274, 1959, Paris.

7. Ruddle CJ: Microendodontic nonsurgi-cal retreatment, in Microscopes inEndodontics, Dent Clin of North Am41:3, pp. 429-454, W.B. Saunders,Philadelphia, July 1997.

8. Carr GB: Ch. 24, Retreatment. In CohenS, Burns RC, editors: Pathways of thePulp, 7th ed., Mosby, St. Louis, pp.791-834, 1998.

9. Ruddle CJ: Ch. 25, Nonsurgicalendodontic retreatment. In Cohen S,Burns RC, editors: Pathways of thePulp, 8th ed., Mosby, St. Louis, pp.875-929, 2001.

10. James Lowe Productions, producer:Ruddle on retreatment, 4-tape videoseries, Advanced Endodontics, SantaBarbara, 2000.

11. Ruddle CJ: Ch. 8, Cleaning and shap-ing root canal systems. In Cohen S,Burns RC, editors: Pathways of thePulp, 8th ed., Mosby, St. Louis, pp.231-291, 2001.

12. Studio 2050, producer: Ruddle onclean•shape•pack, 2-tape videoseries, Advanced Endodontics, SantaBarbara, 2002.

Figure 9a. A pre-operative radiographof a maxillary canine demonstrates atemporized canal with an instrumentbroken deep in the apical one-third.

Figure 9b. A working film shows thatthe 21 gauge iRS has successfullyengaged and partially elevated thedeeply positioned file segment.

Figure 9c. A post-operative filmdemonstrates the retreatment steps anda densely packed system that exhibitsthree apical portals of exit.

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