INTRODUCTION
Endodontic irrigation is one of the major cornerstones of successful endodontic therapy. Several goals need to be accomplished to effectively clean the most apical portions of the canal system. These include proper access to the canal, adequate shaping of the system with rotary files, and appropriate depth of placement of an irrigation needle in the canal. These goals can often be accomplished with any number of burs, files systems, or irrigation needles. However, not every case will fit the cookie-cutter methods and, therefore, adjustments will need to be made to the usual and customary protocol. Oftentimes, conventional needle irrigation is inadequate in its capability to clean the apical third of the canal of both debris and bacteria. In cases such as these, alternative irrigation methods need to be considered. The EndoVac (Kerr Endodontics) system has several advantages over conventional needle irrigation due to its ability to safely deliver sodium hypochlorite (NaOCl) to the full working length without the risk of apical extrusion. These advantages include improved debris removal and disinfection of the root canal system, especially in curved canals; relative safety and minimal risk of hypochlorite accidents in large open-apex canals; and the ability to deliver large amounts of irrigant, which enhances the cleaning and identification of lateral and hidden canals (Figure 1).
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| Figure 1. Confocal images taken at the Louisiana State University School of Dentistry showing (a) the amount of live (green) and (b) dead (red) bacteria before and after EndoVac irrigation. (Image courtesy of Dr. Charles David Ratcliff and Zezhang “Tom” Wen, PhD [New Orleans].) |
Ultimately, the success of irrigation is dependent upon having the irrigant in contact with either pulp tissue (in vital cases) or bacteria (in necrotic cases).1 The fluid extends very little past the terminal end of the needle, thus placement of the needle close to working length is very important if one wants to maximize the effectiveness of irrigation.2 However, binding of the needle can increase the risk of extrusion and the possibility of a hypochlorite accident.3 Canal curvature, needle gauge, and preparation size can all have a significant effect on the depth of penetration of the irrigation needle.4
Applications
While straight canals do exist, practitioners are most often dealing with a curved canal. Even the canals that appear straightest on the radiograph have a significant amount of curvature in the buccal-lingual direction.5 Of course, some canals are curved much more than others, and the cases previously presented, such as in Figure 2, represent situations where a conventional 30-gauge needle will not reach much farther than the coronal or middle third of the canal without binding. The EndoVac MicroCannula (Figure 3) can be inserted right to working length in these cases, resulting in irrigation that is not possible with a conventional irrigation needle.
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| Figure 2. Apical curvatures that would prevent the placement of a conventional needle to working length. (Figure 2b provided by Dr. Charles David Ratcliff.) |
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| Figure 3. (a) EndoVac MicroCannula and (b) EndoVac MacroCannula (Kerr Endodontics). |
Though it will feel like the cannula will bind, there is no risk of extrusion because no positive pressure is used.6 The cannula will suction the irrigant from the pulp chamber and will not introduce irrigant at the apex (Figure 4).
However, some canals are very straight and large. This would be the case with immature open-apex anterior teeth. These teeth, especially if they have a periapical lesion, carry a high risk of irrigant extrusion due to increased contact with the periapical tissue and the high cytotoxicity of NaOCl.7 In these cases, the MacroCannula can be used at working length, due to the large size of the canal, with little to no risk of a hypochlorite accident. EndoVac has been shown to extrude less irrigant than other endodontic irrigation systems, including both conventional and ultrasonic needle irrigation8,9 (Figure 5).
It’s well-known that, in cross-section, root canals are more oval than round and that our instruments leave a significant amount of the canal wall untouched and unprepared.10 There are many cases in which the untouched area of the canal is greater than the area that one can debride, and these include C-shaped canals and defects from resorption. In these circumstances, we must rely heavily on irrigant cleaning for most of the canal. The best way to do this is to use a nondiluted ~6% (full strength) NaOCl solution, because it has been shown to be better at rendering bacteria nonviable, while also physically dissolving tissue and removing the biofilm, when compared to reduced (3% and 1%) concentrations of NaOCl.11 Increasing the concentration of NaOCl is one way to increase the effectiveness of NaOCl; another way is increasing the amount used.12 The EndoVac allows for the safe use of a large volume of a concentrated solution, especially in open-apex cases (Figure 6).
Several studies have highlighted the ability of EndoVac to remove debris from the canal system.13,14 Besides allowing us to penetrate dentinal tubules and further disinfect the canal space, it affords one more advantage: the cleaner the canal, the more easily identifiable additional canals are. These could include missed canals from previous treatments, canals that bifurcate, and/or even canals that trifurcate. Oftentimes, these appear as no more than a small speck on the lateral surface of a canal wall—something that could easily be missed if filled with dentinal debris.
CASE REPORT
Diagnosis and Treatment Planning
A 60-year-old woman presented to the office for a limited examination on tooth No. 10 (left lateral incisor). She complained of pain to palpation in her gums and tenderness of the tooth when her removable partial denture was seated. (Figure 7).
Medically, she had hypertension which was well-controlled with 5 mg of Lisinopril orally once daily.
No swellings or sinus tracts were noted. Probing depths ranged from 2.0 to 3.0 mm with no bleeding upon probing. Tooth No. 10 was tender to percussion and palpation, and nonresponsive to cold. A radiolucency was noted at the apex and mid-root in the canal space. A radiopacity was also noted and sent for radiographic review A CBCT scan was taken to determine the extent of the internal resorptive defect. The tooth was diagnosed with pulp necrosis and symptomatic apical periodontitis. Root canal therapy was recommended to the patient.
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| Figure 4. (a) Open-apex anterior teeth have a greater risk of extrusion. (b) A cleaned lateral canal corresponding to a lateral periapical radiolucency. |
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| Figure 5. (a) Internal resorptions and (b) C-shaped molars require advanced irrigation protocols. |
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| Figure 6. Removal of debris can reveal (a) middle mesial canals and (b) bifurcations of canal systems. |
Clinical Protocol
Local anesthetic (4% Articaine [with 1:100,000 epi]) was administered at 1.5 carpules via buccal and palatal infiltration. The tooth was isolated using a dental dam, and a small conservative access was prepared. A precurved file was used to locate the canal apical to the defect, and then an electronic foramen locator was used to determine the working length. The canal space was shaped using precurved rotary files to negotiate the defect. The EndoVac Master Delivery Tip (MDT) (Kerr Endodontics) was used to introduce 6% NaOCl into the canal space during flaring and between files (Figure 8). Next, the MacroCannula was shaped and then placed into the defect, and 20 cc of NaOCl was introduced with the MDT (Figure 9).
Following irrigation of the internal resorption, the MicroCannula was placed to working length. The canal was irrigated with 10 cc of NaOCl, followed by 3 cc of ethylenediaminetetraacetic acid to remove the smear layer, and then with another 10 cc of NaOCl. Next, the canal was dried with the MicroCannula. A radiograph was taken of the MicroCannula in place to confirm the length of the canal prior to placing an interappointment medicament. Calcium hydroxide was then placed into the canal space. The access was temporarily restored with a sterile sponge and Cavit (3M) (Figure 10).
The patient returned 2 weeks later for completion of the root canal. The patient reported complete resolution of her symptoms. No tenderness to biting or percussion was noted at this appointment. Local anesthetic (4% Articaine [with 1:100,000 epi]) was administered at one carpule via buccal and palatal infiltration. The tooth was isolated with a rubber dam (Hygenic Dental Dam [Coltene]) and re-accessed. The EndoVac protocol utilized in the first appointment was repeated, and the canals were dried with paper points. Sealer (AH Plus [Densply Sirona]) was applied to the canal walls. Next, the tooth was obturated with gutta-percha using the warm vertical compaction technique. The access was again temporarily restored with Cavit.
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| Figure 7. (a) Preoperative periapical image of tooth No. 10. (b) CBCT cross-section showing extent of resorption. |
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| Figure 8. (a) Precurved rotary file. (b) EndoVac Master Delivery Tip (MDT) (Kerr Endodontics) and the MacroCannula in use. |
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| Figure 9. (a) MicroCannula placed at length. (b) MDT and MicroCannula in use. |
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| Figure 10. (a) Calcium hydroxide in the canal space. (b) Master cone placement. (c) Postoperative radiograph (note the complete obturation of the internal resorption). |
CLOSING COMENTS
The safety and efficacy of the EndoVac system in endodontics is well-established in scientific literature. Clinically, its use can potentially result in the elimination of sodium hypochlorite accidents, the identification of additional canals, and the enhanced removal of vital and necrotic nerve tissue in complex anatomies.
References
- Hand RE, Smith ML, Harrison JW. Analysis of the effect of dilution on the necrotic tissue dissolution property of sodium hypochlorite. J Endod. 1978;4:60-64.
- Chow TW. Mechanical effectiveness of root canal irrigation. J Endod. 1983;9:475-479.
- Hülsmann M, Hahn W. Complications during root canal irrigation—literature review and case reports. Int Endod J. 2000;33:186-193.
- Psimma Z, Boutsioukis C, Kastrinakis E, et al. Effect of needle insertion depth and root canal curvature on irrigant extrusion ex vivo. J Endod. 2013;39:521-524.
- Cunningham CJ, Senia ES. A three-dimensional study of canal curvatures in the mesial roots of mandibular molars. J Endod. 1992;18:294-300.
- Khan S, Niu LN, Eid AA, et al. Periapical pressures developed by nonbinding irrigation needles at various irrigation delivery rates. J Endod. 2013;39:529-533.
- Spangberg L, Engström B, Langeland K. Biologic effects of dental materials. 3. Toxicity and antimicrobial effect of endodontic antiseptics in vitro. Oral Surg Oral Med Oral Pathol. 1973;36:856-871.
- Desai P, Himel V. Comparative safety of various intracanal irrigation systems. J Endod. 2009;35:545-549.
- Yost RA, Bergeron BE, Kirkpatrick TC, et al. Evaluation of 4 different irrigating systems for apical extrusion of sodium hypochlorite. J Endod. 2015;41:1530-1534.
- Peters OA, Laib A, Göhring TN, et al. Changes in root canal geometry after preparation assessed by high-resolution computed tomography. J Endod. 2001;27:1-6.
- Clegg MS, Vertucci FJ, Walker C, et al. The effect of exposure to irrigant solutions on apical dentin biofilms in vitro. J Endod. 2006;32:434-437.
- Stojicic S, Zivkovic S, Qian W, et al. Tissue dissolution by sodium hypochlorite: effect of concentration, temperature, agitation, and surfactant. J Endod. 2010;36:1558-1562.
- Nielsen BA, Baumgartner JC. Comparison of the EndoVac system to needle irrigation of root canals. J Endod. 2007;33:611-615.
- Siu C, Baumgartner JC. Comparison of the debridement efficacy of the EndoVac irrigation system and conventional needle root canal irrigation in vivo. J Endod. 2010;36:1782-1785.
Dr. Lally graduated from the University of Detroit Mercy School of Dentistry (2012) and, immediately afterwards, completed an endodontic residency program at Louisiana State University School of Dentistry (New Orleans) and earned his specialty certificate in endodontics (2014). Upon completion of the endodontic program, Dr. Lally joined Valley Endodontic Specialty Group in Tucson, Ariz. He can be reached via email at tlally01@gmail.com.
Disclosure: Dr. Lally receives honoraria from Kerr Dental for articles he publishes.
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