• Proceedings of the KACD Conference
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• 2002.11a
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• pp.720-720
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• 2002

A number of investigations have shown that the presence of bacteria is prerequisite for developing pulpal and/or periradicular pathosis. Depending on the stage of pulpal pathosis, various species of bacteria can be cultured from infected root canals. Kakehashi et al. showed that exposure of pulpal tissue in germ-free rats was characterized by minimal inflammation and dentinal bridging while exposure of pulpal tissue in conventional rats with normal oral flora was characterized by pulpal necrosis, chronic inflammation, and periapical lesions. Currently used methods of cleaning and shaping, especially rotary instrumentation techniques, produce a smear layer that covers root canal walls and the openings to the dentinal tubules. The smear layer contains inorganic and organic substances that include fragments of odontoblastic processes, microorganisms, their by products and necrotic materials. Because of its potential contamination and adverse effect on the outcome of root canal therapy, it seems reasonable to suggest removal of the smear layer for disinfection of the entire root canal system. Presence of this smear layer prevents penetration of intracanal medications into the irregularities of the root canal system and the dentinal tubules and also prevents complete adaptation of obturation materials to the prepared root canal surfaces. Removal of the smear layer by an intracanal irrigant and placement of an antibacterial agent in direct contact with the content of dentinal tubules should allow disinfection of this complex system and better outcome for the root canal therapy. A new solution, which was a mixture of a tetracycline, an acid, and a detergent(MTAD), was developed in the Department of Endodontics, Dental School. Lorna Linda University, USA. It has been demonstrated that MTAD was an effective solution for the removal of the smear layer and does not significantly change the structure of the dentinal tubules when used as a final irrigant in conjunction with 1 % NaOCl as a root canal irrigant. Studies are in progress to compare the anti- microbial properties of this newly developed solution with those of sodium hypochlorite and EDTA that are currently used to irrigate the root canals and remove the smear layer from the surfaces of instrumented root canals.canals.

• Restorative Dentistry and Endodontics
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• v.36 no.3
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• pp.180-187
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• 2011

Introduction: Eliminating the residual debris and bacteria in the root canal system is one of the main purposes of the endodontic treatment. However, the complexity on the anatomy of the root canal system makes it difficult to eliminate the bacterial biofilm existing along the root canal surface and necrotic pulp tissue by mechanical instrumentation and chemical irrigation. Recently, more effective irrigant delivery systems for root canal irrigation have been developed. The purpose of this review was to present an overview of root canal irrigant delivery techniques and devices available in endodontics. Review: The contents of this paper include as follows; - syringe-needle irrigation, manual dynamic irrigation, brushes - sonic and ultrasonic irrigation, passive ultrasonic irrigation, rotary brush, RinsEndo, EndoVac, Laser Conclusion: Though technological advances during the last decade have brought to fruition new agitation devices that rely on various mechanisms, there are few evidence based study to correlate the clinical efficacy of these devices with improved outcomes except syringe irrigation with needle and ultrasonic irrigation. The clinicians should try their best efforts to deliver antimicrobial and tissue solvent solutions in predictable volumes safely to working length.

• Restorative Dentistry and Endodontics
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• v.9 no.1
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• pp.107-114
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• 1983

The purpose of this study was to observe the effect of cleansing action of irrigation solutions which was 3% $H_2O_2$ and 5% NaOCl, and 15% EDTA solution on the root canal wall. After treatment with the irrigant, each sample was dehydrated, and coated with 200~250${\circ}$A of gold, and observations were made with the use of scanning electron microscope. The results were as follows: 1. In the root canal walls irrigated with 3% $H_2O_2$ and 5% NaOCl solution without instrumentation after extirpation through barbed broach, the predentin of root canal wall was found scarely affected, and the wall was shown retaining network structure and fibrous organic matters. 2. When 15% EDTA was applied as irrigants for 60, 90 and 120 seconds after instrumentation, there was no signigicant difference of the cleansing effect of the elapsed times which were 90 and 120 seconds on the root canal wall, but in the applied time which was 120 seconds, the canal wall was the cleanest. Therefore it was thought that the most suitable application time of 15% EDTA as the irigants was 120 seconds.

• Restorative Dentistry and Endodontics
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• v.42 no.1
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• pp.54-59
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• 2017

Objectives: The purpose of this study was to compare the antibacterial activity of urushiol against Enterococcus faecalis (E. faecalis) to that of NaOCl. Materials and Methods: The canals of thirty two single rooted human teeth were instrumented with Ni-Ti files (ProTaper Next X1, X2, X3, Dentsply). A pure culture of E. faecalis ATCC 19433 was prepared in sterile brain heart infusion (BHI) broth. The teeth were submerged in the suspension of E. faecalis and were incubated at $37^{\circ}C$ for 7 days to allow biofilm formation. The teeth were randomly divided into three experimental groups according to the irrigant used, and a negative control group where no irrigant was used (n = 8). Group 1 used physiologic normal saline, group 2 used 6% NaOCl, and group 3 used 10 wt% urushiol solution. After canal irrigation, each sample was collected by the sequential placement of 2 sterile paper points (ProTaper NEXT paper points, size X3, Dentsply). Ten-fold serial dilutions on each vials, and 100 µL were cultured on a BHI agar plate for 8 hours, and colony forming unit (CFU) analysis was done. The data were statistically analyzed using Kruskal-Wallis and Mann-whitney U tests. Results: Saline group exhibited no difference in the CFU counts with control group, while NaOCl and urushiol groups showed significantly less CFU counts than saline and control groups (p < 0.05). Conclusions: The result of this study suggests 10% urushiol and 6% NaOCl solution had powerful antibacterial activity against E. faecalis when they were used as root canal irrigants.

• Restorative Dentistry and Endodontics
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• v.24 no.4
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• pp.578-584
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• 1999

The purpose of this experiment was to determine: (1) the safe automatic apical reverse setting that prevents overinstrumentation of the root canal, using Tri Auto ZX$^{(R)}$ and (2) the effect of various irrigant on such instrumentation. The instrumentation was carried out with the automatic apical reverse setting of 0.5, 1.0, 1.5, and 2.0. The root canal irrigants used in usual manner were normal saline(0.9%), NaOCl(2.5%), and RC Prep$^{(R)}$. For each reverse setting and each irrigant, ten teeth were used with the total of 120 teeth. The distance between the file tip and the apical constriction was determined by stereomicroscope using the point that the file began to rotate in reverse direction. When the reverse setting mode was set to 0.5, 18 of 30 were overinstrumented. If these were discriminated by irrigant, 10 of 6 with 0.9% saline, 10 of 6 with NaOCl, and 10 of 6 with RC Prep$^{(R)}$ has the file tip located 0.57${\pm}$0.30mm, 0.73${\pm}$0.39mm, and 0.26${\pm}$0.25mm beyond the apical constriction respectively. In 1.0 setting 15 of 29 were over the apical constriction, and the distribution was 6 in saline, 5 in NaOCl, and 4 in RC Prep$^{(R)}$. The mean distance over the apical constriction was 0.28${\pm}$0.13mm with saline, 0.75${\pm}$0.61mm with NaOCl, and 0.25${\pm}$0.17mm with RC Prep$^{(R)}$. When the autoatic reverse mode was set to 1.5, and 2.0, 5, and 1 teeth were found to be overinstrumented in respective settings. But there were large variations in overinstrumented distances when an attempt was made to compare the effect of irrigants on this overinstrumentations and they were meaningless for the small sample size. When all of the autoreverse setting were combined to compare the number of overinstrumented teeth with each irrigant, there were no significant differences (14 for normal saline, 12 for NaOCl, 13 for RC Prep$^{(R)}$). When 0.5 or 1.0 automatic apical reverse setting mode was used the Tri Auto ZX$^{(R)}$ in clinical application, the possibility of overinstrumentation beyond the apical constriction exists in 55.9% of cases. Therefore 1.5 or 2.0 setting is safer for the preparation inside the canal but this type setting needs additional apical hand preparation of the root canal because the accuracy is lower than 0.5 or 1.0 setting.

• Restorative Dentistry and Endodontics
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• v.8 no.1
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• pp.147-153
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• 1982

The purpose of this study is to observe the effect of cleansing action of irrigation solutions which are 3% hydrogen peroxide, 5% sodium hypochlorite and 15% EDTA solution on the root canal wall. After the root canal wall is enlarged with K-file in distilled water, the canal wall which is irrigated with each irrigant for 2 minutes, is compared with the. control group without using any irrigants. Each sample is dehydrated, and coated with 200-250${\AA}$ of gold, and observations are made with the use of scanning electron microscope. The results are as follows: 1. The canal walls irrigated with 3% hydrogen peroxide, 5% sodium hypochlorite and 15% EDTA solution are cleaner than the walls without using irrigants. 2. There are no significant difference of cleansing effect among 3% hydrogen peroxide, 5% sodium hypochlorite and 15% EDTA. 3. After using 3% hydrogen peroxide and 5% sodium hypochlorite solution, large debris are removed on root canal walls, but micro debris remain on the canal walls. 4. The root canal walls irrigated with 15% EDTA solution are decalcifed slightly and show clean surfaces.

• Restorative Dentistry and Endodontics
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• v.48 no.1
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• pp.1.1-1.11
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• 2023

Objectives: This study evaluated the dentinal penetration depth of 2.5% sodium hypochlorite (NaOCl) in root canals with and without preparation and different irrigant activation protocols. Materials and Methods: Sixty-three bovine mandibular incisors were randomly allocated to 6 groups (n = 10): G1, preparation + conventional needle irrigation (CNI); G2, preparation + passive ultrasonic irrigation (PUI); G3, preparation + Odous Clean (OC); G4, no preparation + CNI; G5, no preparation + PUI; G6, no preparation + OC; and CG (negative control; n = 3). Samples were filled with crystal violet for 72 hours. Irrigant activation was performed. Samples were sectioned perpendicularly along the long axis, 3 mm and 7 mm from the apex. Images of the root thirds of each block were captured with a stereomicroscope and analyzed with an image analysis software. One-way analysis of variance, followed by the Tukey post hoc test, and the Student's t-test were used for data analysis, with a significance level of 5%. Results: The NaOCl penetration depth was similar when preparation was performed, regardless of the method of irrigation activation (p > 0.05). In the groups without preparation, G6 showed greater NaOCl penetration depth (p < 0.05). The groups without preparation had a greater NaOCl penetration depth than those with preparation (p = 0.0019). Conclusions: The NaOCl penetration depth was similar in groups with root canal preparation. Without root canal preparation, OC allowed deeper NaOCl penetration. The groups without preparation had greater NaOCl penetration than those undergoing root canal preparation.

• Restorative Dentistry and Endodontics
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• v.46 no.1
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• pp.10.1-10.16
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• 2021

Root canal debridement, which includes the removal of infected tissues and microbial biofilms, is considered the corner stone of root canal treatment. Chemical adjuncts play a multitude of functions in this regard, as tissue solvents, antimicrobial agents and for removing the smear layer. These adjuncts (irrigants) are usually delivered using a syringe and needle. With increasing knowledge of the complexity of root canal anatomy and tenacity of microbial biofilms, the need for strategies that potentiate the action of these irrigants within the root canal system cannot be overemphasized. Several such activated irrigation strategies exist. The aim of this review is to comprehensively discuss the different irrigant activation methods from the context of clinical studies.

• Restorative Dentistry and Endodontics
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• v.31 no.2
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• pp.119-124
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• 2006

The purpose of this study was to evaluate the effect of newly developed endodontic root canal cleanser (MTAD) on the apical leakage of obturated root canal using an electrochemical method. Canals of 60 extracted single-rooted human teeth were prepared by using a crown-down technique with rotary nickel-titanium files. In Group 1 (positive control group) and 2 (negative centre) group), 5.25% NaOCl was used as a canal irrigant and no canal wall treatment was done. In group 3 only 5.25% NaOCl were used as canal irrigant, canal wall treatment and final rinse. In group 4, specimens were irrigated with 5.25% NaOCl, treated with 5 ml of 17% EDTA for 5 minutes and final rinsed with 5.25% NaOCl Specimens of group 5 were irrigated with 1 3% NaOCl and treated with 5 ml of MTAD for 5 minutes. All root canals are dried with paper points and obtuated with gutta-percha and AH plus as a sealer using a continuous wave of condensation technique except in the group 1. The electrical resistance between the standard and experimental electrodes in canals was measured over a period of 10 days. Rising of apical leakage with time was observed for all the groups. Group 4 and 5 showed lower apical leakage than group 3 but differences between the group 3, 4 and 5 were no statistical significance at any measurement time.

• Proceedings of the KACD Conference
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• 2001.05a
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• pp.259-259
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• 2001

;A new root canal instrument and instrumentation technique: a preliminary report. Cleaning and shaping the root canal system has been and continues to be a challenge for even the most experienced endodontist. Curved. narrow canals. in particular. cause difficulties for the beginner as well as the specialist. A new instrument designed to incorporate new concepts was developed to ameliorate the problems in cleaning and shaping root canal systems. This new instrument has been given the name of SW (Senia and Wildey). The new SW instrument uses controlled right and left rotational forces. This motion was used to clean and shape simulated root canals in plastic blocks and root canals in extracted teeth. Instrumentation appeared to be easier. faster. and more precise than with conventional instruments. especially in curved canals where there was remarkable reduction of canal transportation. A mechanical version of the SW instrument was also developed. It was used to flare the coronal portion of the root canal system. Wildey WL. Senia ES., Oral Surg Oral Med Oral Pathol1989 Feb:67(2):198-207 Another look at root canal instrumentation. Several aspects of root canal instrumentation need additional research. Various factors must be considered in an analysis of instrumentation of the root canal system: the dentin that is cut: the technique used to cut it: the design of the instruments: the material and manufacturing process used to make the instruments: the irrigant used during the procedure: and the anatomic configuration of the root canal system. An analysis of these factors clearly indicates that existing root canal instruments and techniques are less than ideal and. in fact. do not accomplish what is expected of them. Root canals must be properly. but. at the same time. destructive and unnecessary removal of dentin should be kept to a minimum. The Flex-R and Canal Master instruments were developed to address some of the shortcomings of existing instruments and techniques. More scientifically based research is needed to fully evaluate these new instruments and techniques and to develop future instruments. Wildey WL; Senia ES. Montgomery S., Oral Surg Oral Med Oral Pathol1992 Oct:74(4):499-50799-507