3 CE credits This course was written for dentists, dental hygienists, and assistants.
Safety and Efficacy Considerations in Endodontic Irrigation A Peer-Reviewed Publication Written by Gary Glassman DDS, FRCD(C)
Publication date: January 2011 Expiry date: December 2013
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Educational Objectives The overall goal of this article is to provide the reader with information on endodontic irrigation. On completion of this course, the reader will be able to: 1. List and describe the challenges for successful endodontic treatment 2. List and describe the different types of root canal irrigants, their relative advantages and disadvantages 3. List and describe root canal irrigation systems 4. Describe and explain a sodium hypochlorite incident 5. List and describe the steps that can be taken to avoid a sodium hypochlorite incident.
The challenge for successful endodontic treatment has always been the removal of vital and necrotic remnants of pulp tissues, debris generated during instrumentation, the dentin smear layer, microorganisms, and microtoxins from the root canal system.9 Figure 1. Root canal complex
Abstract Endodontic treatment is a predictable procedure with high success rates. Success depends on a number of factors, including appropriate instrumentation, successful irrigation and decontamination of the root canal space to the apices and in areas such as isthmuses. These steps must be followed by complete obturation of the root canals, and placement of a coronal seal, prior to restorative treatment. Several irrigants and irrigation systems are available, all of which behave differently and have relative advantages and disadvantages. Common root canal irrigants include sodium hypochlorite, chlorhexidine gluconate, alcohol, hydrogen peroxide and ethylenediaminetetraacetic acid (EDTA). In selecting an irrigant and technique, consideration must be given to their efficacy and safety.
Introduction With the introduction of modern techniques, endodontic success rates of up to 98% are being achieved.1 The ultimate goal of endodontic treatment per se is the prevention or treatment of apical periodontitis such that there is complete healing and an absence of infection,2 while the overall long-term goal is the placement of a definitive, clinically successful restoration and preservation of the tooth. For these to be achieved, appropriate instrumentation, irrigation and decontamination, and root canal obturation must occur, as well as attainment of a coronal seal. There is clear evidence that apical periodontitis is a biofilm-induced disease.3 A biofilm is an aggregate of microorganisms in which cells adhere to each other and/or to a surface. These adherent cells are frequently embedded within a self-produced matrix of extracellular polymeric substance. The presence of microorganisms embedded in a biofilm and growing in the root canal system is a key factor for the development of periapical lesions.4,5,6,7 Additionally, the root canal system has a complex anatomy that consists of arborizations, isthmuses, and cul-de-sacs that harbor organic tissue and bacterial contaminants.8 2
Courtesy of Dr. Charles J. Goodis. In: Mandibular Molar Endodontic Treatment.
Even with the use of rotary instrumentation, the nickel-titanium instruments currently available only act on the central body of the root canal, resulting in a reliance on irrigation to clean beyond what may be achieved by these instruments.10 In addition, Enterococcus faecalis and Actinomyces israeliiâ€”which are both implicated in endodontic infections as well as in endodontic failureâ€”penetrate deep into the dentinal tubules, making their removal through mechanical instrumentation impossible.11,12 Finally, Enterococcus faecalis commonly expresses multiple drug resistance,13,14,15 further complicating treatment. Therefore, a suitable irrigant and irrigant delivery system are essential for efficient irrigation and the success of endodontic therapy.16 Not only should root canal irrigants be effective for dissolution of the organic component of the dental pulp, they must also effectively eliminate bacterial contamination and remove the smear layerâ€”the organic and inorganic layer that is created on the wall of the root canal during instrumentation. The ability to deliver irrigants to the root canal terminus in a safe manner without causing harm to the patient is as important as the efficacy of those irrigants.
Root Canal Irrigants Over the years, many irrigating agents have been used and tried in order to achieve tissue dissolution and bactewww.ineedce.com
rial decontamination. The desired attributes of a root canal irrigant include the ability to dissolve necrotic and pulpal tissue, bacterial decontamination and a broad antimicrobial spectrum, the ability to enter deep into the dentinal tubules, biocompatibility and lack of toxicity, the ability to dissolve inorganic material and remove the smear layer, ease of use, and moderate cost. Table 1. Desirable root canal irrigant attributes Bacterial decontamination Broad spectrum antimicrobial activity Ability to enter deep into dentinal tubules Ability to dissolve necrotic tissue Ability to dissolve inorganic material Safety Biocompatibility Lack of toxicity Ease of use Moderate cost Root canal irrigants currently in use include hydrogen peroxide, sodium hypochlorite, ethylenediaminetetraacetic acid (EDTA), alcohol, and chlorhexidine gluconate. Chlorhexidine gluconate offers a wide antimicrobial spectrum, the main bacteria associated with endodontic infections (Enterococcus faecalis and Actinomyces israelii) are sensitive to it, and it is biocompatible with no tissue toxicity for the periapical or surrounding tissues.17 Chlorhexidine gluconate, however, lacks the ability to dissolve necrotic tissue, which limits its usefulness. Hydrogen peroxide as a canal irrigant helps to remove debris by the physical act of irrigation as well as through effervescing of the solution. However, while an effective antibacterial irrigant, hydrogen peroxide also does not dissolve necrotic intracanal tissue, and exhibits toxicity to the surrounding tissues. Cases of tissue damage and facial nerve damage have been reported following use of hydrogen peroxide as a root canal irrigant.18 Alcohol-based canal irrigants also have antimicrobial activity, but will not dissolve necrotic tissue. Table 2. Common root canal irrigants Chlorhexidine gluconate Sodium hypochlorite Alcohol Hydrogen peroxide EDTA The irrigant that satisfies most of the requirements for a root canal irrigant is sodium hypochlorite (NaOCl).19,20 It has the unique ability to dissolve necrotic tissue and the www.ineedce.com
organic components of the smear layer.19,21,22 It also kills sessile endodontic pathogens organized in a biofilm.23,24 There is no other root canal irrigant that can meet all these requirements, even with the use of methods such as lowering the pH,25,26,27 increasing the temperature,28,29,30,31,32 or adding surfactants to increase the wetting efficacy of the irrigant.33,34 However, although sodium hypochlorite appears to be the most desirable single endodontic irrigant, it cannot dissolve inorganic dentin particles and thus cannot prevent the formation of a smear layer during instrumentation.35 Calcifications hindering mechanical preparation are frequently encountered in the canal system, further complicating treatment. Demineralizing agents such as EDTA have therefore been recommended as adjuvants in root canal therapy.20,36 Thus, in contemporary endodontic practice, dual irrigants such as sodium hypochlorite (NaOCl) with EDTA are often used as initial and final rinses to circumvent the shortcomings of a single irrigant.37,38,39 These irrigants must be brought into direct contact with the entire canal wall surfaces for effective action,20,37,40 particularly for the apical portions of small root canals.9 The combination of sodium hypochlorite and EDTA has been used worldwide for antisepsis of root canal systems. The concentration of sodium hypochlorite used for root canal irrigation ranges from 2.5% to 6%, depending on the country and local regulations; it has been shown, however, that tissue hydrolyzation is greater at the higher end of this range, as demonstrated in a study by Hand et al comparing 2.5% and 5.25% sodium hypochlorite. The higher concentration may also favor superior microbial outcomes.41 NaOCl has a broad antimicrobial spectrum,20 including but not limited to Enterococcus faecalis. Sodium hypochlorite is also second to none among irrigating agents that dissolve organic matter. EDTA is a chelating agent that aids in smear layer removal and increases dentin permeability,42,43 which will allow further irrigation with NaOCl to penetrate deep into the dentinal tubules.44
The combination of sodium hypochlorite and EDTA has been used worldwide for antisepsis of root canal systems. General Safety Precautions Regardless of which irrigant and irrigation system is employed, and particularly if an irrigant with tissue toxicity is used, there are several general precautions that must be followed. A rubber dam must be used and a good seal obtained to ensure that no irrigant can spill from the pulp chamber into the oral cavity. If deep caries or a fracture is present adjacent to the rubber dam on the tooth being isolated, a temporary sealing material must be used prior to performing the procedure to ensure a good rubber dam seal. It is also important to protect the patientâ€™s eyes with safety glasses and protect clothing from irrigant splatter or spill. 3
It is very important to note that while sodium hypochlorite has unique properties that satisfy most requirements for a root canal irrigant, it also exhibits tissue toxicity that can result in damage to the adjacent tissues, including nerve damage should sodium hypochlorite incidents occur during canal irrigation. Furthermore, Salzgeber reported in the 1970s that apical extrusion of an endodontic irrigant routinely occurred in vivo;45 this highlights the importance of using devices and techniques that minimize or prevent this. Sodium hypochlorite incidents are further discussed later in this article.
Regardless of which irrigant and irrigation system is used, a rubber dam must be used and a good seal obtained. Irrigant Delivery Systems Root canal irrigation systems can be divided into two categories: manual agitation techniques and machine-assisted agitation techniques.9 Manual irrigation includes positive pressure irrigation, which is commonly performed with a syringe and a side-vented needle. Machine-assisted irrigation techniques include sonics and ultrasonics, as well as newer systems such as the EndoVac® (Discus Dental, Culver City, CA) , which delivers apical negative pressure (ANP) irrigation,46 the plastic rotary F® File (Plastic Endo, Lincolnshire, IL),47,48 the Vibringe® (Vibringe BV, Amsterdam, The Netherlands),49 the RinsEndo® (Air Techniques Inc., NY),9 and the EndoActivator® (Dentsply Tulsa Dental Specialties, Tulsa, OK).9 Two important factors that should be considered during the process of irrigation are whether the irrigation system can deliver the irrigant to the whole extent of the root canal system, particularly at the apical third, and whether the irrigant is capable of debriding areas that could not be reached with mechanical instrumentation, such as lateral canals and isthmi. When evaluating irrigation of the apical third, the phenomenon of apical vapor lock should be considered.50,51,52 Apical Vapor Lock Since roots are surrounded by the periodontium, and unless the root canal foramen is open, the root canal behaves like a close-ended channel. This produces an apical vapor lock effect that resists displacement during instrumentation and final irrigation, thus preventing the flow of irrigant into the apical region and adequate debridement of the canal system.53,54 Apical vapor lock also results in gas entrapment at the apical third.9 During irrigation, sodium hypochlorite reacts with organic tissue in the root canal system, and the resulting hydrolysis liberates abundant quantities of ammonia and carbon dioxide.55 This gaseous mixture is trapped in the apical region and quickly forms a column of gas into which further fluid penetration is impossible. Extension of instruments into this vapor lock does not reduce or remove the gas bubble,56 just as it does not enable adequate flow of irrigant. 4
Apical vapor lock prevents the flow of irrigant into the apical region of roots and also results in gas entrapment at the apical third. The phenomenon of apical vapor lock has been confirmed in studies where roots were embedded in a polyvinylsiloxane (PVS) impression material to restrict fluid flow through the apical foramen, simulating a close-ended channel. The result in these studies was incomplete debridement of the apical part of the canal walls with the use of a positive pressure syringe delivery technique.57,58,59,60 Micro-CT scanning and histological tests conducted by Tay et al have also confirmed the presence of apical vapor lock.60 In fact, studies conducted without ensuring a close-ended channel cannot be regarded as conclusive on the efficacy of irrigants and the irrigant system.61,62,63 The apical vapor lock may also explain why, in a number of studies, investigators were unable to demonstrate a clean apical third in sealed root canals.59,64,65,66 Figure 2a. Close-ended channel
Figure 2b. Open-ended channel
Courtesy of Dr. Franklin Tay
In a paper published by Chow in 1983, based on research he determined that traditional positive pressure irrigation had virtually no effect apical to the orifice of the irrigation needle in a closed root canal system.67 Fluid exchange and debris displacement were minimal. Equally important to his primary findings, Chow set forth an infallible paradigm for endodontic irrigation: “For the solution to be mechanically effective in removing all the particles, it has to: (a) reach the apex; (b) create a current (force); and (c) carry the particles away.”67 The apical vapor lock and consideration for the patient’s safety have always prevented the thorough cleaning of the apical 3 mm. It is critically important to determine which irrigation system will effectively irrigate the apical third as well as isthmi and lateral canals,16 and in a safe manner that prevents the extrusion of irrigant.
An effective irrigant must reach the apex, create a current and remove particles. www.ineedce.com
Manual Agitation Techniques By far the most common and conventional set of irrigation techniques, manual irrigation involves dispensing of an irrigant into a canal through needles/cannulae of variable gauges, either passively or with agitation by moving the needle up and down the canal space without binding it on the canal walls. This allows good control of needle depth and the volume of irrigant that is flushed through the canal.9,63 However, the closer the needle tip is positioned to the apical tissue, the greater the chance of apical extrusion of the irrigant.67,68 This must be avoided; if sodium hypochlorite were to extrude past the apex there is a chance that a catastrophic accident could occur.69
Manual-Dynamic Irrigation Manual dynamic irrigation involves gently moving a well-fitting gutta-percha master cone up and down in short 2 mm to 3 mm strokes within an instrumented canal, thereby producing a hydrodynamic effect and significant irrigant exchange.70 Recent studies have shown that this irrigation technique is significantly more effective than an automated-dynamic irrigation system and static irrigation.9,71,72 Figure 3. Manual Dynamic Max-I-Probe速
Machine-Assisted Agitation Systems Sonic Irrigation Sonic activation has been shown to be an effective method for disinfecting root canals, operating at frequencies of 1-6 kHz.73,74 There are several sonic irrigation devices on the market. The Vibringe allows delivery and sonic activation of the irrigating solution in one step. It employs a 2-piece syringe with a rechargeable battery. The irrigant is sonically activated, as is the needle that attaches to the syringe. The EndoActivator System is a more recently introduced sonically driven canal irrigation system. 9,75 It consists of a portable handpiece and three types of disposable polymer tips of different sizes. The EndoActivator has been reported to effectively clean debris from lateral canals, remove the smear layer, and dislodge clumps of biofilm within the curved canals of molar teeth.9 www.ineedce.com
Figure 4. Sonic irrigation systems
Ultrasonics Ultrasonic energy produces higher frequencies than sonic energy but low amplitudes, oscillating at frequencies of 2530 kHz.9,76 Two types of ultrasonic irrigation are available for use. The first type is simultaneous ultrasonic instrumentation and irrigation (UI), and the second type is referred to as passive ultrasonic irrigation operating without simultaneous irrigation (PUI). The literature indicates that it is more advantageous to apply ultrasonics after completion of canal preparation rather than as an alternative to conventional instrumentation.9,20,77 PUI irrigation allows energy to be transmitted from an oscillating file or smooth wire to the irrigant in the root canal by means of ultrasonic waves.9 There is consensus that PUI is more effective than syringe . needle irrigation in removing pulpal tissue remnants and dentin debris.78,79,80 This may be due to the much higher velocity and volume of irrigant flow that are created in the canal during ultrasonic irrigation.9,81 PUI has been shown to remove the smear layer; there is a large body of evidence with different concentrations of NaOCl.9,80,82,83,84 In addition, numerous investigations have demonstrated that the use of PUI after hand or rotary instrumentation results in a significant reduction of the number of bacteria,9,85,86,87 or achieves significantly better results than syringe needle irrigation.9,84,88,89 Studies have demonstrated that effective delivery of irrigants to the apical third can be enhanced by using ultrasonic and sonic devices.79,81,90,91,92 However, some recent studies have shown that once a sonic or ultrasonically activated tip leaves the irrigant and enters the apical vapor lock, acoustic microstreaming and/or cavitation becomes physically impossible,93 which is not the case with the apical negative pressure irrigation technique.46,94 Consider the erroneous idea that acoustic microstreaming or cavitation that occurs during PUI can clean any part of the apical portion filled with gas (apical vapor lock). Acoustic microstreaming is defined as the movement of fluids along cell membranes, which occurs as a result of the ultrasound energy creating mechanical pressure changes within the tissue. Cavitation is defined as the formation and collapse of gas- and vapor-filled bubbles or cavities in a fluid. 5
This process (cavitation) results from the creation and collapse of microbubbles in the liquid. Acoustic microstreaming or cavitation is only possible in fluids/liquids, not in gases. Therefore, as previously mentioned, it is physically impossible for acoustic microstreaming and/or cavitation to disrupt the apical vapor lock..56 Other studies have shown that sonic or ultrasonic activation might allow a better removal of pulpal tissue remnants and debris from isthmi and fins.79,81 Although ultrasonics can effectively clean debris and bacteria from the root canal system, they still have the drawback of not being able to effectively get through the apical vapor lock in the apical 3 mm of the canal.
Ultrasonics can effectively clean debris and bacteria from the root canal system, but cannot effectively get through the apical vapor lock. The Plastic Rotary F File Although sonic or ultrasonic instrumentation is more effective in removing residual canal debris than rotary endodontic files95 and irrigation solutions are often unable to remove this during endodontic treatment, many clinicians still do not incorporate it in their endodontic instrument armamentarium. The common reasons given for not using sonic or ultrasonic filing are that it can be time-consuming to set up, an unwillingness to incur the cost of the equipment, and lack of awareness of the benefits of this final instrumentation step in endodontic treatment. It is for these reasons that an endodontic polymer-based rotary finishing file was developed. This new, single-use, plastic rotary file has a unique file design with a diamond abrasive embedded into a nontoxic polymer. The F File will remove dentinal wall debris and agitate the sodium hypochlorite without further enlarging the canal. Pressure Alternation Devices RinsEndo irrigates the canal by using pressure-suction technology. Its components are a handpiece, a cannula with a 7 mm exit aperture, and a syringe carrying irrigant. The handpiece is powered by a dental air compressor and has an irrigation speed of 6.2 ml/min. Research has shown that it has promising results in cleaning the root canal system, but more research is required to provide scientific evidence for its efficacy. Periapical extrusion of irrigant has been reported with this device.96,97
The EndoVac Apical Negative Pressure System The EndoVac apical negative pressure irrigation system has three components: The Master Delivery Tip, MacroCannula and MicroCannula. The Master Delivery Tip simultaneously delivers and evacuates the irrigant. The MacroCannula is used to suction irrigant from the chamber to the coronal and middle segments of the canal. The MacroCannula or MicroCannula is connected via tubing to the high-speed suction of a dental unit. The Master Delivery Tip is connected to a syringe of irrigant and the evacuation hood is connected via tubing to the high-speed suction of a dental unit.56 The plastic MacroCannula has an ISO size 0.55 mm diameter open end with a .02 taper and is attached to a Handpiece for gross, initial flushing of the coronal and mid-length parts of the root canal. The MicroCannula contains 12 microscopic holes and is capable of evacuating debris to full working length.97 The ISO size 0.32 mm diameter stainless steel MicroCannula has four sets of three laser-cut, laterally positioned, offset holes adjacent to its closed end, 100 microns in diameter and spaced 100 microns apart. This is attached to a Fingerpiece for irrigation of the apical part of the canal when it is positioned at the working length. The MicroCannula can be used in canals that are enlarged with endodontic files to ISO size #35/.04 or larger. Figure 6a. EndoVac Multi-Port Adapter
Figure 6b. EndoVac instruments Master Delivery Tip
Figure 5. RinsEndo MicroCannula with venting
During irrigation, the Master Delivery Tip delivers irrigant to the pulp chamber and siphons off the excess irrigant to prevent overflow. Both the MacroCannula and MicroCannula exert negative pressure that pulls irrigant from its fresh supply in the chamber, down the canal to the tip of the cannula, into the cannula, and out through the suction hose. Thus, a constant flow of fresh irrigant is being delivered by negative pressure to working length. A recent study showed that the volume of irrigant delivered was significantly higher than the volume delivered by conventional syringe needle irrigation during the same time period,46 and resulted in significantly more debris removal at 1 mm from the working length than did needle irrigation. During conventional root canal irrigation, clinicians must be careful when determining how far an irrigation needle is placed into the canal. Recommendations for avoiding NaOCl incidents include not binding the needle in the canal, not placing the needle close to working length, and using a gentle flow rate when using positive pressure irrigation.98 With the EndoVac, in contrast, irrigant is pulled into the canal at working length and removed by negative pressure. Apical negative pressure has been shown to enable irrigants to reach the apical third and help overcome the issue of apical vapor lock.46,99 In addition, with respect to isthmus cleaning, although it is not possible to reach and clean the isthmus area with instruments, it is not impossible to reach and totally clean these areas with NaOCl when the method of irrigation is safe and efficacious. In studies comparing the EndoActivator,100 passive ultrasonic,100 the F File,100 the Manual Dynamic Max-I-Probe, 100,101 the Pressure Ultrasonic,95 and the EndoVac,101 only the EndoVac was capable of cleaning 100% of the isthmus area.
The EndoVac uses negative pressure, pulls irrigant into the canal to working length and removes it with suction.
urement requiring multiple corrective surgical procedures,105 permanent paresthesia with loss of facial muscle control,69 andâ€”the least significant consequenceâ€”tooth loss.106 Table 2. Potential sequelae of sodium hypochlorite extrusion through the apex Ecchymosis Widespread tissue trauma Tooth loss Facial disfigurement Permanent paresthesia Loss of facial muscle control Irreversible muscle atrophy Life-threatening airway obstruction Although the exact etiology of the NaOCl incident is still uncertain, based on the evidence from actual incidents and the location of the associated tissue trauma, it would appear that an intravenous injection may be the cause. The patient shown in Figure 7 demonstrates a widespread area of tissue trauma that is in contrast to the characteristics of sodium hypochlorite incident trauma reported by Pashley.103,107 This extensive trauma, and particularly involving the pattern of ecchymosis around the eye, could only occur if the sodium hypochlorite were introduced intravenously to a vein close to the root apex through which extrusion of the irrigant occurred, and the irrigant then found its way into the venous complex. This would require positive pressure apically that exceeded venous pressure (10 mg of Hg). In one in vitro study, which used a positive pressure needle irrigation technique to realistically mimic clinical conditions and techniques, the apical pressure generated was found to be 8 times higher than the normal venous pressure.108 Figure 7. Widespread tissue trauma
Apart from being able to avoid air entrapment, the EndoVac system is also advantageous in its ability to safely deliver irrigants to working length without causing their undue extrusion into the periapex,46,97 thereby avoiding sodium hypochlorite incidents. It is important to note that it is possible to create positive pressure in the pulp canal if the Master Delivery Tip is misused, which would create the risk of a sodium hypochlorite incident. The manufacturerâ€™s instructions must be followed for correct use of the Master Delivery Tip.
Sodium Hypochlorite Incidents Although a devastating endodontic sodium hypochlorite (NaOCl) incident is a rare event,102 the cytotoxic effects of sodium hypochlorite on vital tissue have been well established.103 The associated sequelae of NaOCl extrusion have been reported to include life-threatening airway obstructions,104 facial disfigwww.ineedce.com
Figure 8. Irreversible musculature atrophy
when apical negative pressure irrigation was performed (EndoVac) rather than apical positive pressure irrigation.110
The use of apical negative pressure needle irrigation results in safer delivery of sodium hypochlorite, and less post-operative pain.
This does not imply that NaOCl can or should be excluded as an endodontic irrigant; in fact, its use is critical, as has been discussed in this article. What this does imply is that it must be safely delivered. Safety First To compare the safety of six current intracanal irrigation delivery devices, an in vitro test was conducted using the worstcase scenario of apical extrusion, with neutral atmospheric pressure and an open apex.97 The study concluded that the EndoVac did not extrude irrigant after deep intracanal delivery and suctioning of the irrigant from the chamber to full working length, whereas other devices did. The EndoActivator extruded only a very small volume of irrigant, the clinical significance of which is not known. Figure 9. Comparative extrusion of irrigant using irrigation devices Extrusion of irrigant (%)
100 80 60 40 20
Efficacy In vitro and in vivo studies have demonstrated greater removal of debris from the apical walls and a statistically cleaner result using apical negative pressure irrigation in closed root canal systems with sealed apices. In an in vivo study of 22 teeth by Siu and Baumgartner, less debris remained at 1 mm from working length using apical negative pressure compared to use of traditional needle irrigation, while Shin et al found in an in vitro study of 69 teeth comparing traditional needle irrigation with apical negative pressure that these methods both resulted in clean root canals but that apical negative pressure resulted in less debris remaining at 1.5 mm and 3.5 mm from working length.46, 99,111 When comparing root canal debridement using manual dynamic agitation or the EndoVac for final irrigation in a closed system and an open system, it was found that the presence of a sealed apical foramen adversely affected debridement efficacy when manual dynamic agitation was used, but did not adversely affect results when the EndoVac was used. Apical negative pressure irrigation is an effective method to overcome the fluid dynamic challenges inherent in closed canal systems.112
Apical negative pressure irrigation results in greater removal of debris and a cleaner result at working length. Microbial Control Hockett et al tested the ability of apical negative pressure to remove a thick biofilm of Enterococcus faecalis, finding that these specimens rendered negative cultures obtained within 48 hours while those irrigated using traditional positivepressure irrigation were positive at 48 hours.94 Figure 10 shows a scanning electron microscope image of decontaminated dentinal tubules after use of apical negative pressure irrigation with sodium hypochlorite and use of EDTA. Figure 10. SEM of decontaminated dentinal tubules
e r re la to ula do ob nu ssu Pr nn En iva e t s n I a r c x Ca oC Rin eP c oA Ma icr cro nd itiv soni a M s E M Po ltra U
Mitchell and Baumgartner tested irrigant Irrigation system used(NaOCl) extrusion from a root canal sealed with a permeable agarose gel.109 Significantly less extrusion occurred using the EndoVac system compared with positive pressure needle irrigation. A well-controlled study by Gondim et al found that patients experienced less postoperative pain, measured objectively and subjectively, 8
Courtesy of Dr. Jeffrey L. Hockett and Dr. Nestor Cohenca
One study found apical negative pressure irrigation resulted in similar bacterial reductions to use of apical positive pressure irrigation and a triple antibiotic in immature teeth.113 In a study comparing the use of apical positive pressure irrigation and a triple antibiotic that has been utilized for pulpal regeneration/revascularization in teeth with incompletely formed apices (Trimix=Cipro, Minocin, Flagyl) versus use of apical negative pressure irrigation with sodium hypochlorite, it was found that the results were statistically equivalent for mineralized tissue formation and the repair process.114 Using negative apical pressure and sodium hypochlorite also avoids the risk of drug resistance, tooth discoloration, and allergic reactions.115,116
Conclusion Since the dawn of contemporary endodontics, dentists have been syringing sodium hypochlorite into the root canal space and then proceeding to place endodontic instruments down the canal in the belief that they were carrying the irrigant to the apical termination. Biological, SEM, light microscopy, and other studies have proven this belief to be in error. Sodium hypochlorite reacts with organic material in the root canal and quickly forms micro gas bubbles at the apical termination that coalesce into a single large apical vapor bubble with subsequent instrumentation. Since the apical vapor lock cannot be displaced via mechanical means, it prevents further sodium hypochlorite flow into the apical area. Additionally, acoustic microstreaming and cavitation are limited to liquids and have no effect inside the vapor lock. The only method yet discovered to eliminate the apical vapor lock is to evacuate it via apical negative pressure. This method has also been proven to be safe because it always draws irrigants to the source via suction—down the canal and simultaneously away from the apical tissue in abundant quantities.117 When the proper irrigating agents are delivered safely to the full extent of the root canal terminus, thereby removing 100% of organic tissue and 100% of the microbial contaminants, success in endodontic treatment may be taken to levels never seen before.
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Friedman S, Mor C. The success of endodontic therapy—healing and functionality. J Calif Dent Assoc. 2004;32(6):493–503. Orstavik D, Pittford T. Essential endodontology: prevention and treatment of apical periodontitis. 2nd ed. Ames, IA: Blackwell Munksgaard Ltd; 2008:1. Ricucci D, Siqueira JF Jr. Biofilms and apical periodontitis: study of prevalence and association with clinical and histopathologic findings. J Endod. 2010;36(8);1277-88. Fabricius L, Dahlen G, Sundqvist G, et al. Influence of residual bacteria on periapical tissue healing after chemomechanical treatment and root filling of experimentally infected monkey teeth. Eur J Oral Sci. 2006;114:278-85. Siqueira JF Jr, Rocas IN. Clinical implications and microbiology of bacterial persistence after treatment
procedures. J Endod. 2008;34:1291-301. 6 Wong R. Conventional endodontic failure and retreatment. Dent Clin North Am. 2004;48:265-89. 7 Basmadjian-Charles CL, Farge P, Bourgeois DM, Lebrun T. Factors influencing the long-term results of endodontic treatment: a review of the literature. Int Dent J. 2002;52:81-6. 8 Nair PN, Henry S, Cano V, Vera J. Microbial status of apical root canal system of human mandibular first molars with primary apical periodontitis after “one-visit” endodontic treatment. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2005;99:231-52. 9 Gu LS, Kim JR, Ling J, Choi KK, Pashley DH, Tay FR. Review of contemporary irrigant agitation techniques and devices. J Endod. 2009;35(6):791-804. 10 Peters OA. Current challenges and concepts in the preparation of root canal systems: A review. J Endod. 2004;30:559-67. 11 Siqueira JF, de Uzeda M, Fonseca MEF. A scanning electron microscope evaluation of in vitro dental tubules penetration by selected anaerobic bacteria. J Endod. 1996;22:308-10. 12 Haapasalo M. In vitro infection and disinfection of dentinal tubules. J Dent Res. 1987;66:1375-79. 13 Gomes BP, Pinheiro ET, Gade-Neto CR, et al. Microbiological examination of infected dental root canals. Oral Microbiol Immunol. 2004;19:71-6. 14 Orstavik D, Haapasalo M. Disinfection by endodontic irrigants and dressings of experimentally infected dentinal tubules. Endod Dent Traumatol. 1990;6:142-9. 15 Nakajo K, Komori R, Ishikawa S, et al. Resistance to acidic and alkaline environments in the endodontic pathogen Enterococcus faecalis. Oral Microbiol Immunol. 2006;21:283-8. 16 de Gregorio C, Estevez R, Cisneros R, Paranjpe A, Cohenca N. Efficacy of different irrigation and activation systems on the penetration of sodium hypochlorite into simulated lateral canals and up to working length: An in vitro study. J Endod. 2010;36(7):1216-21. 17 Basson N, Tait C. Effectiveness of three root canal medicaments to eliminate Actinomyces israelii from infected dentinal tubules in vitro. S A Dent J. 2000;56:499-501. 18 Kruse A, Hellmich N, Luebbers HT, Grätz KW. Neurological deficit of the facial nerve after root canal treatment. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2009;108(2):e46-8. 19 Paragliola F, Franco V, Fabiani C, et al. Final rinse optimization: Influence of different agitation protocols. J Endod. 2010;36(2):282-5. 20 Zehnder M. Root canal irrigants review. J Endod. 2006;32:389-98. 21 Naenni N, Thoma K, Zehnder M. Soft tissue dissolution capacity of currently used and potential endodontic irrigants. J Endod. 2004;30:785-7. 22 Haikel Y, Gorce F, Allemann C, et al. In vitro efficiency of endodontic irrigation solutions on protein desorption. Int Endod J. 1994;27:16-20. 23 Spratt DA, Pratten J, Wilson M, et al. An in vitro evaluation of the antimicrobial efficacy of irrigants on biofilms of root canal isolates. Int Endod J. 2001;34:300-7. 9
24 Clegg MS, Vertucci FJ, Walker C, Belanger M, Britto LR. The effect of exposure to irrigant solutions on apical dentin biofilms in vitro. J Endod. 2006;32(5):434-7. 25 Cotter JL, Fader RC, Lilley C, Herndon DN. Chemical parameters, antimicrobial activities, and tissue toxicity of 0.1 and 0.5% sodium hypochlorite solutions. Antimicrob Agents Chemother. 1985;28:118-22. 26 Christensen CE, McNeal SF, Eleazer P. Effect of lowering the pH of sodium hypochlorite on dissolving tissue in vitro. J Endod. 2008;34:449-52. 27 Bloomfield SF, Miles G. The relationship between residual chlorine and disinfection capacity of sodium hypochlorite and sodium dichlorisocyanurate solutions in the presence of E. coli and milk. Microbios. 1979;10:33-43. 28 Sirtes G, Waltimo T, Schaetzle M, Zehnder M. The effects of temperature on sodium hypochlorite short-term stability, pulp dissolution capacity, and antimicrobial efficacy. J Endod. 2005;31:669-71. 29 Abou-Rass M, Oglesby SW. The effects of temperature, concentration, and tissue type on the solvent ability of sodium hypochlorite. J Endod. 1981;7:376-7. 30 Cunningham WT, Joseph SW. Effect of temperature on the bactericidal action of sodium hypochlorite endodontic irrigant. Oral Surg Oral Med Oral Pathol. 1980;50:569-71. 31 Cunningham WT, Balekjian AY. Effect of temperature on collagen-dissolving ability of sodium hypochlorite endodontic irrigant. Oral Surg Oral Med Oral Pathol. 1980;49:175-7. 32 Kamburis JJ, Barker TH, Barfield RD, Eleazer PD. Removal of organic debris from bovine dentin shavings. J Endod. 2003;29:559-61. 33 Lui JN, Kuah HG, Chen NN. Effect of EDTA with and without surfactants or ultrasonics on removal of smear layer. J Endod. 2007;33:472-5. 34 Giardino L, Ambu E, Becce C, Rimondini L, Morra M. Surface tension comparison of four common root canal irrigants and two new irrigants containing antibiotic. J Endod. 2006;32:1091-3. 35 Lester KS, Boyde A. Scanning electron microscopy of instrumented, irrigated and filled root canals. Br Dent J. 1977;143:359-67. 36 Nygaard Östby B. Chelation in root canal therapy. Odontol Tidskr. 1957;65:3-11. 37 Grande NM, Plotino G, Falanga A, Pomponi M, Somma F. Interaction between EDTA and sodium hypochlorite: a nuclear magnetic resonance analysis. J Endod. 2006;32:460-4. 38 Kishen A, Sum CP, Mathew S, Lim CT. Influence of irrigation regimens on the adherence of Enterococcus faecalis to root canal dentin. J Endod. 2008;34:850-4. 39 Ringel AM, Patterson SS, Newton CW, Miller CH, Mulhern JM. In vivo evaluation of chlorhexidine gluconate solution and sodium hypochlorite solution as root canal irrigants. J Endod. 1982;8:200-4. 40 Al-Hadlaq SM, Al-Turaiki SA, Al-Sulami U, Saad AY. Efficacy of a new brush-covered irrigation needle in removing root canal debris: a scanning electron microscopic study. J Endod. 2006;32:1181-4. 10
41 Hand RE, Smith ML, Harrison JW. Analysis of the effect of dilution on the necrotic tissue dissolution property of sodium hypochlorite. J Endod. 1978;4(2):60-4. 42 Zehnder M, Schmidlin P, Sener B, et al. Chelation in root canal therapy reconsidered. J Endod. 2005;31:817-20. 43 Surapipongpuntr P, Duangcharee W, Kwangsamai S, et al. Effect of root canal irrigants on cervical dentine permeability to hydrogen peroxide. Int Endod J. 2008;41:821-7. 44 Soares JA, Roque de Carvalho MA, Cunha Santos SM, et al. Effectiveness of chemomechanical preparation with alternating use of sodium hypochlorite and EDTA in eliminating intracanal Entercoccus faecalis biofilm. J Endod. 2010;36(5):894-8. 45 Salzgeber M, Brilliant LD. An in vivo evaluation of the penetration of an irrigating solution in root canals. J Endod. 1974;3(10):394-8. 46 Nielsen BA, Baumgartner JC. Comparison of the endovac system to needle irrigation of root canals. J Endod. 2007;33:611-5. 47 Bahcall J, Olsen FK. Clinical introduction of a plastic rotatory endodontic finishing file. Endo Prac. 2007;10:17-20. 48 Chopra S, Murray PE, Namerow KN. A scanning electron microscopic evaluation of the effectiveness of the F-file versus ultrasonic activation of a K-file to remove smear layer. J Endod. 2008;34:1243-5. 49 Rödig T, Bozkurt M, Konietschke F, Hülsmann M. Comparison of the Vibringe System with syringe and passive ultrasonic irrigation in removing debris from simulated root canal irregularities. J Endod. 2010;36(8):1410-3. 50 Dovgyallo GI, Migun NP, Prokhorenko PP. The complete filling of dead-end conical capillaries with liquid. J Eng Phy. 1989;56:395-7. 51 Migun NP, Azuni MA. Filling of one-side-closed capillaries immersed in liquids. J Coll Interf Sci. 1996;181:337-40. 52 Pesse AV, Warrier GR, Dhir VK. An experimental study of the gas entrapment process in closed-end microchannels. Int J Heat Mass Transfer. 2005;48:5150-65. 53 Senia ES, Marshall FJ, Rosen S. The solvent action of sodium hypochlorite on pulp tissue of extracted teeth. Oral Surg Oral Med Oral Pathol. 1971;31:96-103. 54 de Gregorio C, Estevez R, Cisneros R, Heilborn C, Cohenca N. Effect of EDTA, sonic, and ultrasonic activation on the penetration of sodium hypochlorite into simulated lateral canals: an in vitro study. J Endod. 2009;35:891-5. 55 Kinetics mechanisms hypochlorite oxidation alpha amino acids time water disinfection. Available at: http:// eurekamag.com/research/005/782/kinetics-mechanismshypochlorite-oxidation-alpha-amino-acids-time-waterdisinfection.php 56 Schoeffel GJ. The EndoVac method of endodontic irrigation: part 2—efficacy. Dent Today. 2008;27:82,84,86-87. 57 Baumgartner JC, Mader CL. A scanning electron microscopic evaluation of four root canal irrigation regimens. J Endod. 1987;13:147-57. 58 O’Connell MS, Morgan LA, Beeler WJ, Baumgartner JC. A comparative study of smear layer removal using different salts of EDTA. J Endod. 2000;26:739-43. www.ineedce.com
59 Albrecht LJ, Baumgartner JC, Marshall JG. Evaluation of apical debris removal using various sizes and tapers of ProFile GT files. J Endod. 2004;30:425-8. 60 Tay FR, Gu LS, Schoeffel GJ, et al. Effect of vapor lock on root canal debridement by using a side-vented needle for positivepressure irrigant delivery. J Endod. 2010;36(4):745-50. 61 Torabinejad M, Cho Y, Khademi AA, Bakland LK, Shabahang S. The effect of various concentrations of sodium hypochlorite on the ability of MTAD to remove the smear layer. J Endod. 2003;29(4):233-9. 62 Tinaz AC, Alacam T, Uzun O, Maden M, Kayaoglu G. The effect of disruption of apical constriction on periapical extrusion. J Endod. 2005;31(7):533-5. 63 van der Sluis LW, Gambarini G, Wu MK, Wesselink PR. The influence of volume, type of irrigant and flushing method on removing artificially placed dentine debris from the apical root canal during passive ultrasonic irrigation. Int Endod J. 2006;39(6):472-6. 64 Fukumoto Y, Kikuchi I, Yoshioka T, Kobayashi C, Suda H. An ex vivo evaluation of a new root canal irrigation technique with intracanal aspiration. Int Endod J. 2006;39(2):93-9. 65 Usman N, Baumgartner JC, Marshall JG. Influence of instrument size on root canal debridement. J Endod. 2004;30(2):110-2. 66 Berutti E, Marini R. A scanning electron microscopic evaluation of the debridement capability of sodium hypochlorite at different temperatures. J Endod. 1996;22(9):467-70. 67 Chow TW. Mechanical effectiveness of root canal irrigation. J Endod. 1983;9:475-479. 68 Ram Z. Effectiveness of root canal irrigation. Oral Surg Oral Med Oral Pathol. 1977;44:306-12. 69 Pelka M, Petschelt A. Permanent mimic musculature and nerve damage caused by sodium hypochlorite: a case report. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2008;106(3):e80-3. 70 Machtou P. Irrigation investigation in endodontics. Paris VII University, Paris, France: Master’s thesis; 1980. 71 McGill S, Gulabivala K, Mordan N, Ng YL. The efficacy of dynamic irrigation using a commercially available system (RinsEndo) determined by removal of a collagen ‘bio-molecular film’ from an ex vivo model. Int Endod J. 2008;41:602-8. 72 Huang TY, Gulabivala K, Ng Y-L. A bio-molecular film exvivo model to evaluate the influence of canal dimensions and irrigation variables on the efficacy of irrigation. Int Endod J. 2008;41:60-71. 73 Pitt WG. Removal of oral biofilm by sonic phenomena. Am J Dent. 2005;18:345-52. 74 Ahmad M, Pitt Ford TR, Crum LA. Ultrasonic debridement of root canals: an insight into the mechanisms involved. J Endod. 1987;13:93-101. 75 Ruddle CJ. Endodontic disinfection: tsunami irrigation. Endod Pract. 2008;7-15. 76 Walmsley AD, Williams AR. Effects of constraint on the oscillatory pattern of endosonic files. J Endod. 1989;15:189-94. 77 Weller RN, Brady JM, Bernier WE. Efficacy of ultrasonic www.ineedce.com
cleaning. J Endod. 1980;6:740-3. 78 Sabins RA, Johnson JD, Hellstein JW. A comparison of the cleaning efficacy of short-term sonic and ultrasonic passive irrigation after hand instrumentation in molar root canals. J Endod. 2003;29:674-8. 79 Goodman A, Reader A, Beck M, Melfi R, Meyers W. An in vitro comparison of the efficacy of the step-back technique versus a step-back/ultrasonic technique in human mandibular molars. J Endod. 1985;11:249-56. 80 Cameron JA. The synergistic relationship between ultrasound and sodium hypochlorite: a scanning electron microscope evaluation. J Endod. 1987;13:541-5. 81 Lee SJ, Wu MK, Wesselink PR. The effectiveness of syringe irrigation and ultrasonics to remove debris from simulated irregularities within prepared root canal walls. Int Endod J. 2004;37:672-8. 82 Cameron JA. The use of ultrasonics in the removal of the smear layer: a scanning electron microscope study. J Endod. 1983;9:289-92. 83 Alacam T. Scanning electron microscope study comparing the efficacy of endodontic irrigating systems. Int Endod J. 1987;20:287-94. 84 Huque J, Kota K, Yamaga M, Iwaku M, Hoshino E. Bacterial eradication from root dentine by ultrasonic irrigation with sodium hypochlorite. Int Endod J. 1998;31:242-50. 85 Martin H, Cunningham WT, Norris JP, Cotton WR. Ultrasonic versus hand filing of dentin: a quantitative study. Oral Surg Oral Med Oral Pathol. 1980;49:79-81. 86 Cunningham WT, Martin H, Forrest WR. Evaluation of root canal debridement by the endosonic ultrasonic synergistic system. Oral Surg Oral Med Oral Pathol. 1982;53:401-4. 87 Cunningham WT, Martin H, Pelleu GB Jr., Stoops DE. A comparison of antimicrobial effectiveness of endosonic and hand root canal therapy. Oral Surg Oral Med Oral Pathol. 1982;54:238-41. 88 Spoleti P, Siragusa M, Spoleti MJ. Bacteriological evaluation of passive ultrasonic activation. J Endod. 2003;29:12-4. 89 Weber CD, McClanahan SB, Miller GA, Diener-West M, Johnson JD. The effect of passive ultrasonic activation of 2% chlorhexidine or 5.25% sodium hypochlorite irrigant on residual antimicrobial activity in root canals. J Endod. 2003;29:562-4. 90 Cameron JA. The use of 4 per cent sodium hypochlorite, with or without ultrasound, in cleansing of uninstrumented immature root canals: SEM study. Aust Dent J. 1987;32:204-13. 91 Metzler RS, Montgomery S. Effectiveness of ultrasonics and calcium hydroxide for the debridement of human mandibular molars. J Endod. 1989;15:373-8. 92 Cheung GS, Stock CJ. In vitro cleaning ability of root canal irrigants with and without endosonics. Int Endod J. 1993;26:334-43. 93 Schoeffel GJ. The EndoVac method of endodontic irrigation, part 3: system components and their interaction. Dent Today. 2008;27(106):8-11. 94 Hockett JL, Dommisch JK, Johnson JD, Cohenca N. Antimicrobial efficacy of two irrigation techniques in tapered and nontapered canal preparations: an in vitro study. J 11
Endod. 2008;34:1374-7. 95 Gutarts R, Nusstein J, Reader A, Beck M. In vivo debridement efficacy of ultrasonic irrigation following handrotary instrumentation in human mandibular molars. J Endod. 2005;3:166-170. 96 Pouch D, Bohne W, et al. Cleaning qualities of Rinsendo: an in vitro study. Eur Cells Mater. 2007;13:7. 97 Desai P, Himel V. Comparative safety of various intracanal irrigation systems. J Endod. 2009;35(4):545-9. 98 Hülsmann M, Hahn W. Complications during root canal irrigation: literature review and case reports. Int Endod J. 2000;33:186-93. 99 Shin SJ, Kim HK, Jung IY, Lee CY, Lee SJ, Kim E. Comparison of the cleaning efficacy of a new apical negative pressure irrigating system with conventional irrigation needles in the root canals. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2010 Mar;109(3):479-84. 100 Klyn SL, Kirkpatrick TC, Rutledge RE. In vitro comparisons of debris removal of the EndoActivator System, the F File, ultrasonic irrigation, and NaOCl irrigation alone after handrotary instrumentation in human mandibular molars. J Endod. 2010;36(8):1367-71. 101 Susin L, Parente JM, Loushine RJ, et al. Canal and isthmus debridement efficacies of two irrigant agitation techniques in a closed system. Int Endod J. 2010;43(12):1077-90. 102 Mehdipour O, Kleier DJ, Averbach RE. Anatomy of sodium hypochlorite accidents. Compend Contin Educ Dent. 2007;28(10):544-6. 103 Pashley EL, Birdsong NL, Bowman K, Pashley DH. Cytotoxic effects of sodium hypochlorite on vital tissue. J Endod. 1985;11:525- 8. 104 Bowden JR, Ethunandan M, Brennan PA. Life-threatening airway obstruction secondary to hypochlorite extrusion during root canal treatment. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2006;101(3):402-4. 105 Markose G, Cotter CJ, Hislop WS. Facial atrophy following accidental subcutaneous extrusion of sodium hypochlorite. Br Dent J. 2009;206(5):263-4. 106 Linden J. When Irrigation Leads to Litigation. Dental Products Report. Sept. 2010, 75-81. 107 Hülsmann M, Rödig T, Nordmeyer S. Complications during root canal. Endo Topics. 2009;16:27-63. 108 Boutsioukis C, Verhaagen B, Versluis M, Kastrinakis E, Wesselink PR, van der Sluis PR. Evaluation of irrigant flow in the root canal using different needle types by an unsteady computational fluid dynamics model. J Endod. 2010;36(5):875-97. 109 Mitchell RP, Yang SE, Baumgartner JC. Comparison of apical extrusion of NaOCl using the EndoVac or needle irrigation of root canals. J Endod. 2010;36(2):338-41. 110 Gondim E Jr., Setzer F, dos Carmo CD, Kim S. Postoperative pain after the application of two different irrigation devices in a prospective randomized clinical trial. J Endod. 2010;36;(8):1295-1301. 111 Siu C, Baumgartner JC. Comparison of the debridement efficacy of the EndoVac irrigation system and conventional needle root canal irrigation in vivo. J Endod. 12
2010;36(11):1782-5. 112 Parente JM, Loushine RJ, Susin L, Gu L, Looney SW, Weller RN, et al. Root canal debridement using manual dynamic agitation or the EndoVac for final irrigation in a closed system and an open system. Int Endod J. 2010;43(11):1001-12. 113 Cohenca N, Heilborn C, Johnson JD, Flores DS, Ito IY, da Silva LA. Apical negative pressure irrigation versus conventional irrigation plus triantibiotic intracanal dressing on root canal disinfection in dog teeth. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2010;109(1):e42-6. 114 da Silva LA, Nelson-Filho P, da Silva RA, et al. Revascularization and periapical repair after endodontic treatment using apical negative pressure irrigation versus conventional irrigation plus triantibiotic intracanal dressing in dogs’ teeth with apical periodontitis. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2010;109(5):779-87. 115 Eickholz P, Kim TS, Bürklin T, et al. Nonsurgical periodontal therapy with adjunctive topical doxycycline: a double-blind randomized controlled multicenter study. J Clin Periodontol. 2002;29:108-17. 116 de Paz S, Perez A, Gomez M, Trampal A, Dominguez Lazaro A. Severe hypersensitivity reaction to minocycline. J Invest Allergol Clin Immunol. 1999;9:403-4. 117 Schoeffel GJ. The EndoVac method of endodontic irrigation: Part 4, Clinical Use. Dent Today. 2009;28(6):64, 66-67.
Gary Glassman DDS, FRCD(C) Dr. Gary Glassman graduated from the University of Toronto School of Dentistry in 1984 and graduated from the Endodontology Program at Temple University in 1987 where he received the Louis I. Grossman Study Club Award for academic and clinical proficiency in Endodontics. The author of numerous publications, Dr. Glassman lectures globally on endodontics and is on staff at the University of Toronto, Faculty of Dentistry in the graduate department of endodontics. Gary is a Fellow of the Royal College of Dentists of Canada, and the endodontic editor for Oral Health dental journal. He maintains a private practice, Endodontic Specialists, in Toronto, Ontario, Canada. He can be reached through his website www.rootcanals.ca.
Disclaimer The author of this course has no commercial ties with the sponsors or the providers of the unrestricted educational grant for this course.
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1. Endodontic success rates of up to _______ are being achieved. a. b. c. d.
68% 78% 88% 98%
2. There is clear evidence that apical periodontitis is a _______ disease. a. b. c. d.
fungal viral biofilm-induced all of the above
3. The root canal system contains _______. a. b. c. d.
cul-de-sacs arborizations isthmuses all of the above
4. _______ from the root canal is one of the challenges for successful endodontic treatment. a. b. c. d.
The removal of pulp tissue The removal of debris and the smear layer The removal of microorganisms and microtoxins all of the above
5. The nickel-titanium instruments currently available act on the _______ of the root canal. a. b. c. d.
isthmi central body lateral body all of the above
6. _______ penetrates deep into the dentinal tubules. a. b. c. d.
Actinomyces israelii Candida albicans Enterococcus faecalis a and c
7. To be effective, root canal irrigants must _______. a. b. c. d.
eliminate bacterial contamination remove the smear layer dissolve the organic component of the dental pulp all of the above
8. _______ is a desired attribute for a root canal irrigant. a. b. c. d.
Bacterial decontamination A broad antimicrobial spectrum The ability to enter deep into dentinal tubules all of the above
9. _______ is currently used as a root canal irrigant. a. b. c. d.
Chlorhexidine gluconate Hydrogen peroxide Sodium hypochlorite all of the above
10. Chlorhexidine gluconate _______. a. b. c. d.
offers a wide antimicrobial spectrum is biocompatible lacks the ability to dissolve necrotic tissue all of the above
11. Hydrogen peroxide _______. a. b. c. d.
is an effective antibacterial irrigant exhibits no tissue toxicity dissolves necrotic tissue a and c
12. The irrigant that satisfies most of the requirements for a root canal irrigant is _______. a. b. c. d.
polyalkenoic acid sodium hypochlorite saline chlorhexidine gluconate
13. Sodium hypochlorite _______. a. dissolves necrotic tissue b. dissolves the organic components of the smear layer c. kills sessile endodontic pathogens d. all of the above
14. EDTA has been recommended as an adjuvant in root canal therapy because it is a _______. a. b. c. d.
remineralizing agent dilutant demineralizing agent b and c
15. The combination of _______ has been used worldwide for antisepsis of root canal systems. a. b. c. d.
sodium hypochlorite and calcium chloride EDTA and chlorhexidine gluconate sodium hypochlorite and EDTA all of the above
16. _______ is a general safety precaution prior to root canal irrigation. a. Use of a rubber dam b. Protecting the patient’s eyes with safety glasses c. Use of a temporary sealing material if deep caries is present adjacent to a rubber dam d. all of the above
17. Apical extrusion of an endodontic irrigant _______ occurs. a. b. c. d.
never rarely routinely always
18. Root canal irrigation systems are available that work using _______. a. b. c. d.
manual agitation techniques manual rotation techniques machine-assisted agitation techniques a and c
19. When irrigating the root canal system, it is important to consider if _______. a. the irrigation system can deliver the irrigant to the whole extent of the root canal system b. the irrigant can debride areas that cannot be reached mechanically c. the irrigant contains any dye d. a and b
20. An apical vapor lock effect _______. a. prevents the flow of irrigant into the apical region of the root canal b. results in gas entrapment at the apical third c. resists displacement by instrumentation d. all of the above
21. The _______ of sodium hypochlorite liberates ammonia and carbon dioxide. a. b. c. d.
dessication hydrolysis cross-linking none of the above
22. An apical vapor lock occurs in root canals with _______. a. b. c. d.
an open-ended channel a close-ended channel multiple isthmuses all of the above
23. _______ have confirmed the presence of apical vapor lock. a. b. c. d.
Histological tests Micro-CT scans Radiographs a and b
24. For a root canal irrigant to be mechanically effective in removing all the particles, it has to _______. a. b. c. d.
reach the apex create a current carry the particles away all of the above
25. The apical vapor lock and consideration for the patient’s safety has always prevented the thorough cleaning of the _______. a. b. c. d.
apical 3 mm lateral 3 mm apical 5 mm lateral 5 mm
26. The most common and conventional set of irrigation techniques is _______. a. b. c. d.
mechanical irrigation manual irrigation hydrodynamic theory irrigation all of the above
27. Manual dynamic irrigation produces _______. a. b. c. d.
a hydrodynamic effect effervescence significant irrigant exchange a and c
28. Sonic activation has been shown to be an effective root canal irrigation method, operating at frequencies of _______. a. b. c. d.
1-6 kHz 2-7 kHz 3-8 kHz none of the above
29. Ultrasonic energy _______. a. b. c. d.
produces higher frequencies than sonic energy produces low amplitudes results in oscillations at frequencies of 25-30 kHz all of the above
30. The literature indicates that it is more advantageous to apply ultrasonics _______. a. b. c. d.
as an alternative to conventional instrumentation after completion of canal preparation after initial root canal preparation a and c
31. Passive ultrasonic irrigation _______. a. operates without simultaneous irrigation b. allows energy to be transmitted from an oscillating file or smooth wire to the irrigant c. is the only type of ultrasonic irrigation d. a and b
32. Passive ultrasonic irrigation _______. a. effectively removes pulpal tissue remnants b. effectively removes dentin debris c. results in a significant reduction of the number of bacteria d. all of the above
33. Studies have demonstrated that effective delivery of irrigants to the apical third can be enhanced by using _______ devices. a. b. c. d.
ultrasonic sonic air abrasion a and b
34. Acoustic microstreaming is defined as the movement of _______. a. b. c. d.
sound along cell membranes fluids along cell membranes gases along cell membranes all of the above
35. Once a sonic or ultrasonically activated tip leaves the irrigant and enters the apical vapor lock, _______ becomes physically impossible. a. b. c. d.
acoustic microstreaming cavitation cell death a and/or b
36. Ultrasonics _______. a. can effectively clean bacteria from the root canal system b. can effectively clean debris from the root canal system c. cannot effectively get through the apical vapor lock d. all of the above
37. _______ is a common reason given for not using sonic or ultrasonic filing. a. The time required for set-up b. An unwillingness to incur the equipment costs c. Lack of awareness of the benefits of this final instrumentation step d. all of the above
38. Sonic or ultrasonic activation might allow a better removal of _______. a. b. c. d.
pulpal tissue remnants debris from isthmi debris from fins all of the above
39. An apical negative pressure system contains a _______. a. b. c. d.
Master Delivery Tip MacroCannula MicroCannula all of the above
40. A pressure alternation device consists of _______. a. b. c. d.
a handpiece a cannula with a 7 mm exit aperture a syringe carrying irrigant all of the above
41. With an apical negative pressure system, the cannulae in the canal _______. a. exert negative pressure b. pull irrigant from its fresh supply in the chamber, down the canal to the tip of the cannula c. pull irrigant into the cannula and out through the suction hose d. all of the above
42. Apical negative pressure has been shown to _______. a. b. c. d.
enable irrigants to reach the apical third help overcome the issue of apical vapor lock remove the risk of sodium hypochlorite incidents all of the above
43. A sodium hypochlorite incident occurs when the irrigant _______. a. b. c. d.
extrudes through the root canal foramen is at a concentration above 3% is mixed with a second irrigant all of the above
44. Recommendations for avoiding sodium hypochlorite incidents include _______. a. not binding the needle in the canal b. not placing the needle close to working length
c. using a gentle flow rate d. all of the above
45. _______ is a sequela of a sodium hypochlorite incident. a. Life-threatening airway obstruction b. Permanent paresthesia c. Facial disfigurement d. all of the above
46. Based on the evidence from actual sodium hypochlorite incidents and the location of the associated tissue trauma, it would appear that an _______may be the cause. a. anatomical anomaly b. intravenous injection c. arterial injection d. a and b
47. In an in vitro study comparing intracanal irrigation delivery devices, only the use of a device using _______ resulted in no extrusion at the apex. a. ultrasonics b. apical positive pressure c. apical negative pressure d. sonics
48. The presence of a sealed apical foramen was shown in one study to adversely affect debridement efficacy when _______ was used. a. manual dynamic agitation b. apical negative pressure c. water d. all of the above
49. The only method yet discovered to eliminate the apical vapor lock is to evacuate it via _______. a. apical positive pressure b. apical negative pressure c. acoustic microstreaming d. all of the above
50. Proper root canal irrigation should result in _______. a. safe delivery of the irrigating agent(s) b. removal of 100% of the organic tissue in the canal(s) c. removal of 100% of the microbial contaminants d. all of the above
Safety and Efficacy Considerations in Endodontic Irrigation Name:
Telephone: Home (
Lic. Renewal Date:
Requirements for successful completion of the course and to obtain dental continuing education credits: 1) Read the entire course. 2) Complete all information above. 3) Complete answer sheets in either pen or pencil. 4) Mark only one answer for each question. 5) A score of 70% on this test will earn you 3 CE credits. 6) Complete the Course Evaluation below. 7) Make check payable to PennWell Corp. For Questions Call 216.398.7822
For immediate results, go to www.ineedce.com to take tests online. Answer sheets can be faxed with credit card payment to (440) 845-3447, (216) 398-7922, or (216) 255-6619.
1. List and describe the challenges for successful endodontic treatment 2. List and describe the different types of root canal irrigants, their relative advantages and disadvantages 3. List and describe root canal irrigation systems
P ayment of $59.00 is enclosed. (Checks and credit cards are accepted.)
4. Describe and explain a sodium hypochlorite incident 5. List and describe the steps that can be taken to avoid a sodium hypochlorite incident
If paying by credit card, please complete the following: MC Visa AmEx Discover
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Please evaluate this course by responding to the following statements, using a scale of Excellent = 5 to Poor = 0. 1. Were the individual course objectives met?
O bjective #1: Yes No Objective #2: Yes No Objective #5: Yes No
2. To what extent were the course objectives accomplished overall?
Exp. Date: _____________________ Charges on your statement will show up as PennWell
Objective #3: Yes No Objective #4: Yes No 3
3. Please rate your personal mastery of the course objectives.
4. How would you rate the objectives and educational methods?
5. How do you rate the author’s grasp of the topic?
6. Please rate the instructor’s effectiveness.
7. Was the overall administration of the course effective?
8. Do you feel that the references were adequate?
9. Would you participate in a similar program on a different topic?
10. If any of the continuing education questions were unclear or ambiguous, please list them. ___________________________________________________________________ 11. Was there any subject matter you found confusing? Please describe. ___________________________________________________________________ ___________________________________________________________________ 12. What additional continuing dental education topics would you like to see? ___________________________________________________________________ ___________________________________________________________________ If not taking online, mail completed answer sheet to
Academy of Dental Therapeutics and Stomatology, A Division of PennWell Corp.
P.O. Box 116, Chesterland, OH 44026 or fax to: (440) 845-3447
31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. AGD Code 074
PLEASE PHOTOCOPY ANSWER SHEET FOR ADDITIONAL PARTICIPANTS. AUTHOR DISCLAIMER The author of this course has no commercial ties with the sponsors or the providers of the unrestricted educational grant for this course. SPONSOR/PROVIDER This course was made possible through an unrestricted educational grant from Discus Dental. No manufacturer or third party has had any input into the development of course content. All content has been derived from references listed, and or the opinions of clinicians. Please direct all questions pertaining to PennWell or the administration of this course to Machele Galloway, 1421 S. Sheridan Rd., Tulsa, OK 74112 or macheleg@ pennwell.com. COURSE EVALUATION and PARTICIPANT FEEDBACK We encourage participant feedback pertaining to all courses. Please be sure to complete the survey included with the course. Please e-mail all questions to: email@example.com.
INSTRUCTIONS All questions should have only one answer. Grading of this examination is done manually. Participants will receive confirmation of passing by receipt of a verification form. Verification forms will be mailed within two weeks after taking an examination. EDUCATIONAL DISCLAIMER The opinions of efficacy or perceived value of any products or companies mentioned in this course and expressed herein are those of the author(s) of the course and do not necessarily reflect those of PennWell. Completing a single continuing education course does not provide enough information to give the participant the feeling that s/he is an expert in the field related to the course topic. It is a combination of many educational courses and clinical experience that allows the participant to develop skills and expertise.
COURSE CREDITS/COST All participants scoring at least 70% on the examination will receive a verification form verifying 3 CE credits. The formal continuing education program of this sponsor is accepted by the AGD for Fellowship/Mastership credit. Please contact PennWell for current term of acceptance. Participants are urged to contact their state dental boards for continuing education requirements. PennWell is a California Provider. The California Provider number is 4527. The cost for courses ranges from $49.00 to $110.00. Many PennWell self-study courses have been approved by the Dental Assisting National Board, Inc. (DANB) and can be used by dental assistants who are DANB Certified to meet DANB’s annual continuing education requirements. To find out if this course or any other PennWell course has been approved by DANB, please contact DANB’s Recertification Department at 1-800-FOR-DANB, ext. 445.
Customer Service 216.398.7822
RECORD KEEPING PennWell maintains records of your successful completion of any exam. Please contact our offices for a copy of your continuing education credits report. This report, which will list all credits earned to date, will be generated and mailed to you within five business days of receipt. CANCELLATION/REFUND POLICY Any participant who is not 100% satisfied with this course can request a full refund by contacting PennWell in writing. © 2011 by the Academy of Dental Therapeutics and Stomatology, a division of PennWell
Kills microbes dead. 100% Safe.* 100% Kill. 1 Single Visit. Single-Visit Disinfection is now a Reality Time is valuable for both your patients and your practice. Fortunately, the EndoVac is clinically proven to deliver 100% bacterial kill levels1 with complete safety2 and significantly less post-operative pain3 for your patients. EndoVac delivers dead-on success, the first time around. If the bugs are dead, close the case. “...the present results demonstrated that reliable disinfection can be achievable with efficient and safer irrigation delivery systems, such as the EndoVac system, and that the use of intracanal antibiotics might not be necessary.” Cohenca OOOOE 2010 Jan;109:e42-46
Irrigation Protocol. Easy as 1, 2, 3... 1. EndoVac Master Delivery Tip 2. EndoVac MacroCannula — — Gross Debridement & Disinfection Provides a constant flow of irrigant without the risk of overflow. The MDT is used after each instrument change to remove gross debris arising from instrumentation.
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Debridement & Disinfection Deep in the Canal Removes coarse debris deep inside the canal after all instrumentation is completed.
IAL SPECuC tory d o Intr offEro!de: nC tio MenSP2017
3. EndoVac MicroCannula
— Complete Apical Debridement & Disinfection at Working Length Maximum microbial control using a 0.32 mm cannula and negative pressure to safely draw irrigants to the apical termination and create a vortex-like cleaning of the apical third.
(1) Journal of Endodontics 2008;34:1374-1377 (2) Journal of Endodontics 2009;35:545-549 (3) Journal of Endodontics 2010;36:1295-1301 * The claim “100% Safe” refers to the finding that the EndoVac MicroCannula and MacroCannula produced no extrusion of irrigant apically in the study reported in J Endod 2009;35:545-549. The EndoVac is intended only for the irrigation of root canals during endodontic treatment and only for use according to manufacturer’s instructions. © 2010 Discus Dental, LLC. All rights reserved. ADV-3172 120910 20-2653