|Year : 2020 | Volume
| Issue : 2 | Page : 212-218
Comparison of postoperative pain after foraminal enlargement of necrotic teeth using continuous rotary system and reciprocating instrument: A randomized clinical trial
Department of Endodontics, Faculty of Dentistry, Kutahya Health Sciences University, Kutahya, Turkey
|Date of Submission||16-Aug-2019|
|Date of Acceptance||01-Oct-2019|
|Date of Web Publication||7-Feb-2020|
Mr. S Kurnaz
Department of Endodontics, Faculty of Dentistry, Kutahya Health Sciences University, TR 43270 Kutahya
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Objectives: This single-blind, randomized clinical trial (RCT) aimed to compare the duration, intensity, and incidence of postoperative pain after foraminal enlargement (FE) with continuous rotary systems and reciprocating instruments. Materials and Methods: Sixty qualified patients were randomly divided into the following two groups: the ProTaper Next group and the WaveOne group. Participants were selected from patients who had both asymptomatic necrosis and asymptomatic apical periodontitis with a single root canal. Endodontic treatment was performed in one visit, and the patients were asked to record their pain severity and analgesic consumption during a 7-day follow-up period using a visual analog scale (VAS). The data were analyzed using the Mann–Whitney U-test and Chi-square test (P < 0.05). Results: A significant difference was observed between the two groups during the first two days of follow-up (P < 0.05). Pain experience was higher in FEs that had been created by reciprocating instruments than by continuous rotary systems. There were no significant differences in VAS pain scores over the other days (P > 0.05). None of the patients had severe postoperative pain during the follow-up period. No significant differences were observed in the prevalence of analgesic consumption between either group (P > 0.05). Conclusions: This RCT indicates that in the 2-day follow-up period after endodontic treatment, FEs created by reciprocated instruments associated more postoperative pain than continuous rotary systems.
Keywords: Foraminal enlargement, postoperative pain, reciprocating instrument, rotary system, visual analog scale
|How to cite this article:|
Kurnaz S. Comparison of postoperative pain after foraminal enlargement of necrotic teeth using continuous rotary system and reciprocating instrument: A randomized clinical trial. Niger J Clin Pract 2020;23:212-8
|How to cite this URL:|
Kurnaz S. Comparison of postoperative pain after foraminal enlargement of necrotic teeth using continuous rotary system and reciprocating instrument: A randomized clinical trial. Niger J Clin Pract [serial online] 2020 [cited 2020 Feb 19];23:212-8. Available from: http://www.njcponline.com/text.asp?2020/23/2/212/277870
| Introductıon|| |
The apical part of the root canal is vital to chemomechanical preparation during root canal treatment., Maintaining working length (WL) during root canal treatment is necessary for adequate removal of microorganisms that are considered to be the primary cause of pulpal and periapical diseases. Studies have shown that bacterial biofilms are present in the apical part of the root canal and even within periapical lesions., Therefore, cleaning and shaping of the foraminal region may be essential to obtain satisfactory chemomechanical preparation.
Foraminal enlargement (FE) is defined as an intentional and mechanical enlargement of the apical foramen to improve bacterial removal from the apical portion. Borlina et al. indicated that widening the apical foramen could reduce the microbial load and facilitate periapical healing. Despite the advantages of FE, Siqueira reported that FE can result in an increased incidence of postoperative pain due to direct mechanical irritation of the periapical tissues. In Silva et al.'s evaluation of postoperative pain after widening the apical foramen using hand files, they reported that FE caused the same level of postoperative pain as nonforaminal enlargement (NFE). However, Saini et al. observed that FEs increased the intensity of postoperative pain when they were facilitated with hand files, and Junior et al.and Yaylali et al. reported that FEs resulted in more postoperative pain than NFEs when they were applied with reciprocating instruments or continuous rotary systems.
While different studies, have evaluated the severity of postoperative pain after FEs created by continuous rotary systems or reciprocating instruments, comparisons between these two systems have yet to be assessed. This randomized clinical trial (RCT) was conducted to evaluate and compare postoperative pain after the use of continuous rotary systems and reciprocating instruments. The null hypothesis tested was that there is no difference in the level of postoperative pain after using these two different instrumentation systems.
| Materıals and Methods|| |
This study was a randomized, single-blinded, and single-center clinical trial. It was designed and reported by adhering to the Consolidated Standards of Reporting Trials Statement. The study was approved by the Ethics Committee of Dumlupinar University (ref. no.: 2017-5/2), and the study protocol was registered in the www.clinicaltrials.gov database with the identifier number NCT03380585. All of the participants received written information about the trial and provided written and informed consent for study participation.
This study was conducted on consecutive patients who presented for routine endodontic treatment from the Faculty of Dentistry at Kutahya Health Sciences University's Department of Endodontics in Kutahya, Turkey. After comprehensive clinical and radiological examinations, 79 consecutive subjects (e.g. >18 years of age) were enrolled in the study [Figure 1]. Only patients who had single root canal teeth that had been diagnosed with asymptomatic pulp necrosis and radiographic evidence of apical periodontitis according to periapical radiography (minimum lesion size: 2 × 2 mm) were included. Criteria for exclusion included pregnancy, preoperative pain, systemic disorders, analgesic treatment within the past three days, and treatment with antibiotics over the past 1 month. Only one tooth from each patient was included in the study.
|Figure 1: Consolidated Standards of Reporting Trials flow diagram showing the progress of subjects at each stage of the clinical trial|
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The power analysis was performed according to the minimal-clinically important differences between the visual analogue scale's (VAS) pain scores. Calculation of the sample size indicated that a minimum of 30 participants would be required from each group to identify any significant differences in postoperative pain levels, with an alpha risk of 0.05, a power of 0.9, and an effect size of 0.8.
Sequence generation and blinding
The patients were randomly allocated into two groups with a 1:1 allocation ratio by a random-number-table generator on a computer (www.random.org). Participants were then separated into the two following groups: the ProTaper Next (PTN) group and the WaveOne (WO) group [Table 1]. The patients were blinded and not informed of the allocation. However, the operator (S.K.) was not blinded due to the nature of the interventions. The allocation sequence was placed in sealed, opaque, and sequentially numbered envelopes. Before treatment, the operator opened the sealed envelopes, wherein the type of intervention method was noted.
Using a standardized protocol, the investigator (S.K.) performed entire endodontic treatments during single visits. Pulp vitality was determined using a hot and cold test and confirmed visually by the absence of bleeding during access cavity preparation. In all cases, patients were administered local anesthesia (2% lidocaine with 1:100,000 epinephrine) and then rubber dam isolation was maintained. The access cavity was created using a sterile diamond bur. Working length (WL) was determined using an electronic apex locator (EAL) (Root ZX; J Morita, Tokyo, Japan) and confirmed radiographically. In both groups, instrumentation was performed to the WL maintained at the “APEX” reading (0.0) of the EAL.
Root canals were prepared using the PTN system with a continuous rotary movement speed of 300 rpm and 2 Ncm torque. In this group, the continuous rotary system was powered by the VDW Gold Reciproc Motor (VDW GmbH, Munich, Germany). The instrumentation sequences included X1 (17/04), X2 (25/06), X3 (30/.075), and X4 (40/.06).
In the WO group, the root canals were instrumented using a WO reciprocating single file (40/.08) that applied gentle in-and-out movements at amplitudes that did not exceed 3–4 mm. The instruments were used in reciprocating mode with the VDW Gold Reciproc Motor (VDW GmbH, Munich, Germany).
Between each instrument, irrigation was performed with 2.5% sodium hypochlorite using a 30-G irrigation needle (Max-i-Probe, Dentsply Maillefer). In both groups, canal patency was maintained by passing a size-8 stainless steel hand K-file (Dentsply Maillefer) 1 mm beyond the WL. All teeth were irrigated with the same volume of irrigant (a total of 40 mL). The final rinse was performed using 2.5% sodium hypochlorite and 5% EDTA. In both groups, all teeth were dried using WO and PTN absorbent paper points (Dentsply Maillefer).
Using a continuous-wave condensation technique, the canals were subsequently filled with WO and PTN gutta-percha cones (Dentsply Maillefer) in accordance with the groups that used AH Plus sealer (Dentsply Maillefer). The gutta-percha cones were coated with sealer and were placed to working length. The cone was seared off at the canal orifice and then the remaining material was packed down by using Elements Unit (SybronEndo, Orange, CA) to within 5 mm of the apex. Backfilling the canal was accomplished by using the Elements Backfill Unit until the canal orifice was reached., The obturation level and the quality of root canal filling were confirmed using periapical radiographs. In this way, it was ensured that no overfilling was occured. The final restorations were performed with dentinal adhesive and composite resin (Filtek P60; 3M Dental Products, St Paul, MN). All patients were instructed to take an analgesic (400 mg ibuprofen) if they experienced pain.
Postoperative pain evaluation
Pain levels were measured using a VAS for the first 7 days after endodontic treatment. The VAS was comprised of a horizontal line that measured 100 mm in length from two endpoints that included “no pain” (score of 0) and “pain as bad as it could be” (score of 100). Patients were asked to record their pain by placing a mark along the VAS line where it corresponded to the severity of their postoperative pain. The distances between 0 (no pain) and patients' marks were measured with a ruler to determine the severity of their postoperative pain., Pain severity was rated according to the four categories that follow: no pain (0–4 mm), mild pain (5–44 mm), moderate pain (45–74 mm), and severe pain (75–100 mm). Analgesic intake was also recorded by the patients on their cards.
All statistical analyses were performed using SPSS software (IBM Corp, Armonk, NY). Data normality was analyzed using the Shapiro–Wilk test. The Mann–Whitney U-test, a nonparametric statistical analysis, was used to analyze the independent samples. The Chi-square test was used to evaluate the differences between categoric variables. Comparisons were considered to be statistically significant at P < 0.05.
| Results|| |
In total, 79 patients were screened in this study. Of these, 15 were excluded, and 4 declined participation. There was no loss of patients during follow-up. The mean age (mean ± standard deviation) was 33.3 ± 7.1 years in the WO group and 31.7 ± 8.6 years in the PTN group. No statistically significant differences in age or sex were observed between the two groups (P > 0.05) [Table 2].
The results of this study demonstrated that pain intensity was significantly different between the two groups during the 2 days that followed treatment (P <.05, Mann–Whitney U-test), after which all differences became insignificant. In the WO group, the mean pain scores were higher than those of the PTN group [Table 3].
On the first day after FE, four patients (13%) from the PTN group reported moderate pain, and eight patients (27%) from the PTN group reported mild pain. On the second day, three of these patients (10%) reported moderate pain, and five of these patients (17%) reported mild pain. On the first day after FE, 8 patients (27%) from the WO group reported moderate pain, and 11 patients (37%) from the WO group reported mild pain. On the second day, six of these patients (20%) reported moderate pain, and nine of these patients (30%) reported mild pain. Overall, 18 patients (60%) in the PTN group and 11 patients (37%) in the WO group did not complain of pain [Figure 2].
|Figure 2: Postoperative pain prevalence. PTN = ProTaper Next group; WO = WaveOne group|
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No patients reported severe pain at any point in time. In addition, no serious adverse effect occurred during the follow-up period. Four patients (13%) in the PTN group and seven patients (23%) in the WO group requested analgesics during the first 3 days of follow-up. However, no significant differences were found between the groups in their analgesic consumption (P > 0.05).
| Dıscussıon|| |
This study evaluated the intensity, incidence, and duration of postoperative pain in patients who underwent FEs created by continuous rotary systems and reciprocating instruments. During the first 2 days of follow-up, the study's findings demonstrated that postoperative pain was significantly higher in the WO group than it was in the PTN group. Therefore, the study's null hypothesis was rejected.
No significant differences were observed between the groups in terms of age or sex. Because preoperative pain might have influenced the results, only patients with asymptomatic teeth were included in the study. The creation of FEs is especially practical in teeth with necrotic pulps, as microorganisms can easily penetrate into the apical foramen region in these cases. As a result, only teeth with necrotic pulps with asymptomatic apical periodontitis were included in this study. The only differences between either of the groups of this study were the instrumentation systems that were used to create the FEs. Therefore, all other variables were kept similar between both groups. Finally, to prevent the influence of intracanal medications on the outcome of treatment, all root canals were obturated during single visitations.
The reduction of the microbial load and the deterioration of biofilms are achieved through chemomechanical instrumentation during root canal treatments. It has been claimed that a greater reduction of bacteria and a more effective irrigation can be achieved when larger apical preparations are performed. In spite of the many advantages of FE, it has been reported that postoperative pain can occur due to physical trauma in the periapical region. Although the creation of FEs is associated with postoperative pain and inflammation, this study revealed low incidences of FE-related pain. Like in previous studies, this study recorded the highest levels of postoperative pain during the first 24 h of follow-up.,
Because every patient's pain threshold is different, one of the major obstacles in the study of pain is the subjectivity of its assessment. For this reason, the design of pain-assessment questionnaires is critical to studies that evaluate the subject. In this study, a VAS model was used to evaluate pain. VAS has been reported to be one of the most commonly used methods for measuring pain intensity in pain research. Therefore, VAS was selected for the postoperative evaluation of pain in this study.
The correct determination of the WL is an important step during endodontic treatments. Improvement to EALs and the development of WL-determination techniques have resulted in several accurate estimations of apical constriction. It has also been recommended that the use of an EAL to determine a WL, and confirming WL radiographically, can minimize the chances of error during endodontic treatment. Therefore, this study confirmed its WL radiographically and used the EAL Root ZX (J. Morita), which proved its effectiveness and reliability under various conditions, to determine the apical constriction.
In this study, root canal treatments were performed using continuous rotary systems or reciprocating instruments. At present, several studies have evaluated postoperative pain after root canal treatments using both of these tools. In Kherlakian et al.'s comparison of the incidence of postoperative pain after the endodontic treatment of posterior teeth using a continuous rotary system and two reciprocating instruments, they observed no statistically significant differences among their three study groups in terms of postoperative pain or analgesic medication intake. In comparison, Nekoofar et al. showed that endodontic treatment with reciprocating instruments led to more postoperative pain than endodontic treatment with continuous rotary systems, and Pasqualini et al. demonstrated that reciprocating instruments affected postoperative quality of life more than continuous rotary systems. On the other hand, Junior et al. reported that FEs that had been created with reciprocating instruments resulted in a low incidence of pain, and Yaylali et al. observed that FEs that had been created with continuous rotary systems caused more pain on the first 2 days after root canal treatment. Regardless, it remains to be seen if the incidence of postoperative pain is higher for FEs that have been created with continuous rotary systems or reciprocating instruments.
The results of this study indicated that during the first days after endodontic treatment, FEs that had been created with reciprocating instruments associated more pain than those that had been created with continuous rotary systems. In one systematic review, the use of reciprocating instruments in endodontic treatment was associated with a higher incidence of postoperative pain than rotary systems. These findings are in agreement with the results of the current review. It is well known that debris and bacterial extrusion are associated with postoperative pain after endodontic treatment.In vitro studies have revealed that reciprocating instruments cause a greater amount of apical extrusion than continuous rotary systems., Therefore, the postoperative pain differences between these groups may have been caused by the varying amounts of apical extrusion during root canal instrumentation.
Irrigation is an important step for eliminating microorganisms from the root canal system. The cleaning and disinfection of the root canals depends on the mechanical instrumentation and chemical effects of the irrigant used. The application time of the irrigant plays a significant role in terms of eliminating the bacteria. The continuous rotary systems provide a slower and more gradual mechanical enlargement of the root canals, while reciprocating instruments provide faster mechanical preparations over a short period of time using only one single instrument during endodontic treatment. Therefore, when continuous rotary systems are used during root canal treatment, the application time of irrigation solutions may be longer. Consequently, longer application time of the irrigation solutions may result a greater dissolution of the organic tissues and a higher disinfection, which may have influenced the results of this study.
Yaylali et al. indicated that the creation of FEs with continuous rotary systems resulted in severe postoperative pain for certain patients during the first and second days after endodontic treatment. Regardless, no severe pain was observed in any of the patients of this study. This difference between Yaylali et al.'s study and the current one is likely because their study assessed molar teeth while this one evaluated teeth with single root canals.
In Junior et al.'s study, no patients reported severe pain after the creation of FEs on single root canals with reciprocating instruments. Likewise, in this RCT, no severe postoperative pain was observed after endodontic treatment in the WO group. Similar to this study, Nekoofar et al. demonstrated that root canal treatment with reciprocating instruments caused more postoperative pain than root canal treatment with continuous rotary systems.
While in this RCT, postoperative pain was significantly higher in the WO group than it was in the PTN group, no significant differences were found between either group's analgesic intake. This result is in agreement with previous studies,,, and may be attributed to the fact that every patient's pain threshold is different and that it is their decision to use or forgo the use of analgesics.
Because this clinical study was conducted on patients with necrotic pulp and asymptomatic apical periodontitis, these findings cannot be generalized to teeth with vital pulp that are without apical periodontitis.
| Conclusıons|| |
Within the limitations of this study, while postoperative pain was significantly higher in the WO group than in the PTN group during the first 2 days of follow-up, there were no significant differences between the two groups in terms of analgesic consumption.
The author would like to thank very much to Dr. İbrahim Ethem Yaylali for his valuable contribution to the research.
Financial support and sponsorship
This work was supported by Dumlupinar University's Scientific Research Project Coordination Unit (project number: 2017– 57).
Conflicts of interest
There are no conflicts of interest.
| References|| |
Grossman LI. Physical properties of root canal cements. J Endod 1976;2:166-75.
Simon J. The apex: How critical is it? Gen Dent 1993;42:330-4.
Nair P. On the causes of persistent apical periodontitis: A review. Int Endod J 2006;39:249-81.
Subramanian K, Mickel AK. Molecular analysis of persistent periradicular lesions and root ends reveals a diverse microbial profile. J Endod 2009;35:950-7.
de Paz LC. Redefining the persistent infection in root canals: Possible role of biofilm communities. J Endod 2007;33:652-62.
Saini H, Sangwan P, Sangwan A. Pain following foraminal enlargement in mandibular molars with necrosis and apical periodontitis: A randomized controlled trial. Int Endod J 2016;49:1116-23.
Borlina SC, de Souza V, Holland R, Murata SS, Gomes-Filho JE, Junior ED, et al.
Influence of apical foramen widening and sealer on the healing of chronic periapical lesions induced in dogs' teeth. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;109:932-40.
Siqueira J. Microbial causes of endodontic flare-ups. Int Endod J 2003;36:453-63.
Silva EJNL, Menaged K, Ajuz N, Monteiro MRFP, de Souza Coutinho-Filho T. Postoperative pain after foraminal enlargement in anterior teeth with necrosis and apical periodontitis: A prospective and randomized clinical trial. J Endod 2013;39:173-6.
Junior JAC, Coelho MS, Kato AS, Vivacqua-Gomes N, Fontana CE, Rocha DGP, et al.
The effect of foraminal enlargement of necrotic teeth with the Reciproc System on postoperative pain: A prospective and randomized clinical trial. J Endod 2016;42:8-11.
Yaylali IE, Teke A, Tunca YM. The effect of foraminal enlargement of necrotic teeth with a continuous rotary system on postoperative pain: A randomized controlled trial. J Endod 2017;43:359-63.
Schulz KF, Altman DG, Moher D. CONSORT 2010 Statement: Updated guidelines for reporting parallel group randomised trials. BMC Medicine 2010;8:18.
Arora M, Sangwan P, Tewari S, Duhan J. Effect of maintaining apical patency on endodontic pain in posterior teeth with pulp necrosis and apical periodontitis: A randomized controlled trial. Int Endod J 2016;49:317-24.
Iglecias EF, Freire LG, de Miranda Candeiro GT, Dos Santos M, Antoniazzi JH, Gavini G. Presence of voids after continuous wave of condensation and single-cone obturation in mandibular molars: A micro-computed tomography analysis. J Endod 2017;43:638-42.
Marciano MA, Ordinola-Zapata R, Cunha TV, Duarte MA, Cavenago BC, Garcia RB, et al.
Analysis of four gutta-percha techniques used to fill mesial root canals of mandibular molars. Int Endod J 2011;44:321-9
Wewers ME, Lowe NK. A critical review of visual analogue scales in the measurement of clinical phenomena. Res Nurs Health 1990;13:227-36.
Hawker GA, Mian S, Kendzerska T, French M. Measures of adult pain: Visual Analog Scale for Pain (VAS Pain), Numeric Rating Scale for Pain (NRS Pain), McGill Pain Questionnaire (MPQ), Short-Form McGill Pain Questionnaire (SF-MPQ), Chronic Pain Grade Scale (CPGS), Short Form-36 Bodily Pain Scale (SF-36 BPS), and Measure of Intermittent and Constant Osteoarthritis Pain (ICOAP). Arthritis Care Res 2011;63(Suppl 11):240-52.
Torabinejad M, Kettering JD, McGraw JC, Cummings RR, Dwyer TG, Tobias TS. Factors associated with endodontic interappointment emergencies of teeth with necrotic pulps. J Endod 1988;14:261-6.
Souza RA. The importance of apical patency and cleaning of the apical foramen on root canal preparation. Braz Dent J 2006;17:6-9.
Kherlakian D, Cunha RS, Ehrhardt IC, Zuolo ML, Kishen A, da Silveira Bueno C. Comparison of the incidence of postoperative pain after using 2 reciprocating systems and a continuous rotary system: A prospective randomized clinical trial. J Endod 2016;42:171-6.
Ørstavik D, Ford TRP. Essential Endodontology, Prevention and Treatment of Apical Periodontitis. 1st
ed. Oxford: Blackwell Publishing Ltd.; 1998.
Card SJ, Sigurdsson A, Ørstavik D, Trope M. The effectiveness of increased apical enlargement in reducing intracanal bacteria. J Endod 2002;28:779-83.
Ricucci D. Apical limit of root canal instrumentation and obturation, part 1. Literature review. Int Endod J 1998;31:384-93.
Holland R, Sant'Anna Júnior A, Souza Vd, Dezan Júnior E, Otoboni Filho JA, Bernabé PFE, et al.
Influence of apical patency and filling material on healing process of dogs' teeth with vital pulp after root canal therapy. Braz Dent J 2005;16:9-16.
Arias A, Azabal M, Hidalgo JJ, José C. Relationship between postendodontic pain, tooth diagnostic factors, and apical patency. J Endod 2009;35:189-92.
Jensen MP, Chen C, Brugger AM. Interpretation of visual analog scale ratings and change scores: A reanalysis of two clinical trials of postoperative pain. J Pain 2003;4:407-14.
Plotino G, Grande N, Brigante L, Lesti B, Somma F. Ex vivo
accuracy of three electronic apex locators: Root ZX, elements diagnostic unit and Apex locator and ProPex. Int Endod J 2006;39:408-14.
Martins JN, Marques D, Mata A, Caramês J. Clinical efficacy of electronic apex locators: Systematic review. J Endod 2014;40:759-77.
Herrera M, Ábalos C, Lucena C, Jiménez-Planas A, Llamas R. Critical diameter of apical foramen and of file size using the Root ZX apex locator: An in vitro
study. J Endod 2011;37:1306-9.
Nekoofar MH, Sheykhrezae MS, Meraji N, Jamee A, Shirvani A, Jamee J, et al.
Comparison of the effect of root canal preparation by using WaveOne and ProTaper on postoperative pain: A randomized clinical trial. J Endod 2015;41:575-8.
Pasqualini D, Corbella S, Alovisi M, Taschieri S, Del Fabbro M, Migliaretti G, et al.
Postoperative quality of life following single-visit root canal treatment performed by rotary or reciprocating instrumentation: A randomized clinical trial. Int Endod J 2016;49:1030-9.
Hou X-M, Su Z, Hou B-X. Post endodontic pain following single-visit root canal preparation with rotary vs reciprocating instruments: A meta-analysis of randomized clinical trials. BMC Oral Health 2017;17:86.
Siqueira JF, Rôças IN, Favieri A, Machado AG, Gahyva SM, Oliveira JC, et al.
Incidence of postoperative pain after intracanal procedures based on an antimicrobial strategy. J Endod 2002;28:457-60.
Bürklein S, Schäfer E. Apically extruded debris with reciprocating single-file and full-sequence rotary instrumentation systems. J Endod 2012;38:850-2.
Nayak G, Singh I, Shetty S, Dahiya S. Evaluation of apical extrusion of debris and irrigant using two new reciprocating and one continuous rotation single file systems. J Dent (Tehran, Iran) 2014;11:302.
Retamozo B, Shabahang S, Johnson N, Aprecio RM, Torabinejad M. Minimum contact time and concentration of sodium hypochlorite required to eliminate Enterococcus faecalis. J Endod 2010;36:520-3.
Tinoco JM, De-Deus G, Tinoco EMB, Saavedra F, Fidel RAS, Sassone LM. Apical extrusion of bacteria when using reciprocating single-file and rotary multifile instrumentation systems. Int Endod J 2014;47:560-6.
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[Table 1], [Table 2], [Table 3]