NONSURGICAL ENDODONTIC RETREATMENT - …

1 There has been massive growth in ENDODONTIC treatment inrecent years. This increase in clinical activity can be attributableto better-trained dentists and specialists alike. Necessary forthis unfolding story is the general public's growing selectionfor root canal treatment as an alternative to the time, patients have become more confident selectingendodontic treatment because of the changing perceptionthat pain can be managed, techniques have improved andsuccess is achievable. During the last decade, significant procedural refinements have created greater promise for ourprofession to fulfill the public s growing expectations forlongterm success. This article will focus on the concepts,strategies, and techniques that will produce successfulresults in NONSURGICAL ENDODONTIC canal system anatomy plays a significant role inendodontic success and systems containbranches that communicate with the periodontal attachmentapparatus furcally, laterally, and often terminate apically intomultiple portals of , any opening from theroot canal system (RCS) to the periodontal ligament spaceshould be thought of as a portal of exit (POE) through whichpotential ENDODONTIC breakdown products may ,7 Improvement in the diagnosis and treatment of lesions ofendodontic origin (LEO) occurs with the recognition of theinterrelationships between pulpal disease flow and theegress of irritants along these anatomical pathways (Figure 1).

2 8 ENDODONTIC failures can be attributable to inadequacies inshaping, cleaning and obturation, iatrogenic events, or re-infection of the root canal system when the coronal sealis lost after completion of root canal of the etiology, the sum of all causes is leakageand bacterial ,14 Except in rare instances,lesions of ENDODONTIC origin will routinely heal following theextraction of pulpally involved teeth because the extractionnot only removes the tooth, but more importantly serves toeliminate 100% of the contents of the root canal treatment can approach 100% success discountingteeth that are nonrestorable, have hopeless periodontal disease or have radicular OF NONSURGICAL ENDODONTIC RETREATMENTB efore commencing with any treatment, it is profoundlyimportant to consider all interdisciplinary treatment optionsin terms of time, cost, prognosis and potential for patientsatisfaction.

3 ENDODONTIC failures must be evaluated so adecision can be made among NONSURGICAL RETREATMENT , surgicalNONSURGICALENDODONTICRETREATMENT by Clifford J. Ruddle, JOURNALJune 2004 Figure 1a. A pre-operative film shows the maxillary left first molar sremaining palatal root is endodontically 1b. NONSURGICAL RETREATMENT demonstrates a mesiocrestal lateralcanal, a loop and an apical bifidity. Three-dimensional endodontics isthe foundation of perio-prosthetics. ADVANCEDENDODONTICS , or of nonsurgicalretreatment are to remove materials from the root canalspace and if present, address deficiencies or repair defectsthat are pathologic or iatrogenic in , NONSURGICAL RETREATMENT procedures confirm mechanical failures,previously missed canals or radicular subcrestal , disassembly and corrective procedures allowclinicians to shape canals and three-dimensionally clean andpack root canal ,20 NONSURGICAL ENDODONTIC retreat-ment procedures have enormous potential for success if theguidelines for case selection are respected and the most relevant technologies, best materials and precise techniquesare typically access the pulp chamber through anexisting restoration if it is judged to be functionally designed.

4 Well-fitting and esthetically the restoration isdeemed inadequate and/or additional access is required,then it should be sacrificed. However, on specific occasions,it may be desirable to remove the restoration intact so it canbe re-cemented following ENDODONTIC technologies exist which facilitate the saferemoval of a restorative. Coronal disassembly improvesaccess, vision and the RETREATMENT safe dislodgment of a restoration is dependent on severalfactors such as the type of preparation, the restorative designand strength, the restorative material(s), the cementing agentand knowing how to use the best removal devices. There areseveral important removal devices which may be divided intothree categories: (1) Grasping instruments, such as (GC America)and Wynman Crown Gripper (MiltexInstrument Company), (2) Percussive instruments like thePeerless Crown-a-Matic (Henry Schein) and the Coronaflex(KaVo America), and (3) Passive-active instruments such asthe Metalift (Classic Practice Resources), the Kline CrownRemover (Brasseler)and the Higa Bridge Remover (HigaManufacturing).

5 Clinicians must clearly define the risk versusbenefit with patients before commencing with the safe andintact removal of an existing restorative (Figure 2).Figure 2a. A photograph demonstrates removal of a crown utilizing Pliers. Note the grasping pads have been dipped in emery powder toreduce 2b. A photograph demonstrates bridge removal utilizing theCoronaflex. The air driven hammer generates the removal force againstvarious prosthetic attachment 2c. A photograph demonstrates the removal of a PFM crown utilizing the Metalift. This system applies a force between the crown andthe tooth. canals hold tissue, and at times bacteria and relatedirritants that inevitably contribute to clinical symptoms andlesions of ENDODONTIC , surgical treatmenthas been directed towards corking the end of the canalwith the hopes that the retrograde material will incarceratebiological irritants within the root canal system over the lifeof the this clinical scenario occurs anecdotally, it is not as predictable as NONSURGICAL retreat-ment.

6 ENDODONTIC prognosis is maximized in teeth whoseroot canals are shaped and root canal systems cleaned andpacked in alltheir dimensions (Figure 3).5,8 There are multiple concepts, armamentarium and techniquesthat are useful to locate canals. The most reliable method forlocating canals is to have knowledge regarding root canalsystem anatomy and appreciation for the range of variationcommonly associated with each type of methods for identifying canals include: radiographicanalysis, magnification and lighting (microscopes), completeaccess, firm explorer pressure, ultrasonics, Micro-Openers(Dentsply Tulsa Dental), dyes, sodium hypochlorite, colorand texture, removing restorations, and probing the , if a missed canal is suspected but cannot be readilyidentified and treated, then an ENDODONTIC referral may beprudent to avoid complications.

7 Caution should be exercisedwhen contemplating surgery due to the aforementionedconcerns, but at times may be necessary to retain the are four commonly encountered obturation materialsfound in root canals. These materials are gutta percha, carrier-based obturators, silver points and paste it is necessary to remove an obturation material toachieve ENDODONTIC RETREATMENT success or to facilitate placinga post for restorative reasons. The effective removal of an obturation material requires utilizing the most provenmethods from the past in conjunction with the best presentlydeveloped 3a. A radiograph of a maxillary right second bicuspid revealspins, a post, incomplete endodontics and an asymmetrical 3c. Aphotograph at 12x demonstrates complete access and identification of the lingual 3d. A 10-year recall radiograph shows excellent osseous repair, theimportance of 3-D endodontics , and a well-designed and sealed 3b.

8 A photograph at 12x shows the post is out of the buccal canal,thread marks in the gutta percha from the screw post, and evidence of amissed lingual system. PERCHA REMOVALThe relative difficulty in removing gutta percha variesaccording to the obturation technique previously employedand further influenced by the canal s length, cross-sectionaldimension, curvature and internal configuration. Regardless oftechnique, gutta percha is best removed from a root canalin a progressive manner to prevent inadvertent displacementofirritants periapically. Dividing the root into thirds, guttapercha may be initially removed from the canal in the coronalone-third, then the middle one-third, and finally eliminatedfrom the apical one-third. At times, single cones in largerand straighter canals can be removed with one instrumentin one motion. For other canals, there are a number of possible gutta percha removal removaltechniques include rotary files, ultrasonic instruments,heat, hand files with heat or chemicals, and paper pointswith these options, the best technique(s)for a specific case is selected based on preoperative radiographs, clinically assessing the available diameter ofthe orifices after re-entering the pulp chamber, and clinicalexperience.

9 Certainly, a combination of methods are generallyrequired and, in concert, provide safe, efficient and potentiallycomplete elimination of gutta percha and sealer from theinternal anatomy of the root canal system (Figure 4).NONSURGICALENDODONTICRETREATMENTs4 Figure 4b. A photograph at 8x shows a 45hedstroem mechanicallyremoving the heat softened single cone of gutta pre-operative radio-graph of a maxillarycentral incisordemonstrates inade-quate endodontics ,resorption and apicalone-third post-operative radiograph showsthe NONSURGICAL RETREATMENT result and three-dimensional obturation. POINT REMOVALThe relative ease of removing a silver point is based on thefact that chronic leakage reduces the seal and hence, the lateral retention. Access preparations must be thoughtfullyplanned and carefully performed to minimize the risk of inadvertently foreshortening any given silver point.

10 Initialaccess is accomplished with highspeed, surgical length cuttingtools, then oftentimes ultrasonic instruments are used tobrush-cut away remaining restorative materials and fullyexpose the silver techniques have been developed for removing silverpoints depending on their lengths, diameters, and positionsthey occupy within the root canal space (Figure 5).23,26,27 Certainremoval techniques evolved to address silver points that bindin unshaped canals over distance. Other techniques arose toremove silver points with large cross-sectional diameters,approaching the size of smaller posts. Finally, other techniques are necessary to remove intentionally sectionedsilver points lying deep within the root canal space. The moreeffective methods for removing silver points include: graspingpliers utilizing the principles of fulcrum mechanics, indirectNONSURGICALENDODONTICRETREATMENT s5 Figure 5b.