B U J O D. Original Research

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1 Original Research COMPARISON OF THE EFFICACY OF 17% EDTA, 7% MALEIC ACID & 5% PHOSPHORIC ACID IN SMEAR LAYER REMOVAL FROM INSTRUMENTED HUMAN ROOT CANAL: A SCANNING ELECTRON MICROSCOPIC STUDY.. AUTHORS: Alpa Vora*, Kshiti Shah**, Vaishali Parekh*** ABSTRACT: Objective: The aim of the study was to Compare the efficacy of 17% Ethylenedia-minetetraacetic acid, 7% Maleic acid &5% Phosphoric acid and in smear layer removal from instrumented human root canal. Methodology: 35 single-rooted human Maxillary Central Incisor were subjected to root canal instrumentation (ProTaper-F5). Based on the final irrigating solution used, samples were divided randomly into three groups: (1) the EDTA group: 17% EDTA+ 2.5% NaOCl (n = 10), (2) the Maleic acid group: 7% Maleic acid + 2.5% NaOCl (n = 10), (3) the Phosphoric acid group : 5% Phosphoric aicd + 2.5% NaOCl (n=10)and (4) the control group: 0.9% saline (n = 5). After final irrigation, teeth were prepared for SEM analysis to evaluate the cleaning of the coronal, middle, and apical thirds of radicular dentin by determining the presence or absence of smear layer. The data was statistically analyzed using the Mann-Whitney test & Kruskall- Wallis test. Results: There was significant difference between 7% Maleic acid & 17% EDTA in all thirds of the canals. While, no significant difference was found between 7% Maleic acid & 5% Phosphoric acid. Conclusion: Final irrigation with 7% maleic acid is more efficient than 17%EDTA in the removal of smear layer from the apical third of the root canal system, which is a crucial area for disinfection. Keywords: EDTA, Maleic acid, Phosphoric acid, Smear layer removal, Scanning Electron Microscope INTRODUCTION: The objective of modern endodontic therapy is to clean and shape the root canal system removing all organic material and to seal this system with a permanent three-dimensional filling that does not [1,2] allow leakage. The most commonly used material for root canal obturation is gutta-percha combined with a sealer. Gutta-percha is considered to be an impermeable core material but it does not bond to the root dentin [3] walls. Because of the absence of a chemical union between the gutta-percha and the root canal sealers, ADDRESS FOR CORRESPONDENCE: Dr Alpa Vora, Professor, Department of Conservative and Endodontics, K.M. Shah Dental College and Hospital, Vadodara. establishing a seal in the root canal may be dependent on the ability of the root canal sealer to [4] penetrate into the dentinal tubules. Mechanical instrumentation of the root canal produces a smear layer that covers the dentinal tubules.the smear layer is an amorphous irregular layer containing inorganic dentin debris as well as organic material like pulp tissue, odontoblastic processes, necrotic debris, [6] microorganisms, and their metabolic products. It forms a barrier between the filling material and the sound dentin that inhibits the penetration of irrigants into dentinal tubules, increases the chance of microleakage, and decreases the bond strength of 7 resin based materials. Hence, to improve the sealing of the root canal and reduce further microleakage, it is important to remove the smear [8-12] layer before obturating the canal. *Professor, **PG Student, ***HOD & Professor, Department of Conservative and Endodontics, K.M. Shah Dental College and Hospital, Vadodara 8

2 Vora et al Complete cleaning of the root-canal system requires the use of irrigants that dissolve organic and inorganic material. As Sodium hypochlorite is active [13] only against the organic matter, other substances such as chelating agents can be usefulfor complete removal of the smear layer and dentin debris. Among various chelating agents EDTA, citric acid alone, MTAD (citric acid with mixture of tetracycline isomer (doxycycline) and Tween 80 (a detergent)), etc have been tried. In 1951, the first report on the demineralizing effect of EDTA on dental hard tissue was published by Hahn & Reygadas & is proven that EDTA is most commonly used as a 17% neutralized solution [14] (disodium EDTA, ph 7). Ballal et al in 2009 tried 7% Maleic acid as an option due to its acidic ph & concluded that it is more effective than 17% EDTA. Maleic acid is a mild organic acid used as an acid conditioner in adhesive dentistry.prabhu et al in 2003 tried different concentrations of Maleic acid (5%, 7%, 10%, or 15%) for removal of the smear layer and reported that higher concentration (more than 7%) caused damage to the intertubular dentin [15].Among other acids, Phosphoric acid (5%-37%) which is used to remove the smear layer and smear plugs from coronal cavity preparations also has [7] been tried for root dentin. Comparison have been done between EDTA & Maleic acid and also between EDTA & Phosphoric acid separately. But no comparison have been done between Maleic acid & Phosphoric acid. So, the present study was designed to compare the efficacy of 17% Ethylenediaminetetraacetic Acid, 7% Maleic Acid & 5% Phosphoric Acid in removal of the smear layer from root canal by Scanning Electron Microscopy (SEM) to conclude which regimen best meet our objective with maximum efficiency & minimal damage to the root dentin. 24 MATERIAL & METHODOLOGY: Ethical clearance was obtained from the Ethical Committee of Sumandeep University, Vadodara. 35 Maxillary Central Incisors with closely matched apical diameter (i.e 0.20mm ±0.05mm) and single straight canal were included in the study. Teeth with caries & obturation were excluded from the study. Teeth were stored in 0.5% Chloramine-T solution for disinfection for 24 hours. They were decoronated to standardize the working length of 15 mm. Pulp was removed from canals by Barbed broaches. The samples were divided randomly into three experimental groups (n=10) and a control group (n = 5).The working length was confirmed by introducing a no.10 k-file into the canal until it exits from the apex and the working length was set 1 mm short of canal length. Chemomechanical preparation was performed with a crown-down technique using hand ProTaper files (Dentsply Maillefer, Ballaigues, Switzerland). Apically, the canals were enlarged up to F5. Irrigation was performed with 1 ml of 2.5% of NaOCl solution after each instrument change using 30 guage Max-I Probe (Dentsply Maillefer, Ballaigues, Switzerland). The probe was placed within 1 to 2 mm of the working length in each canal. The final irrigation sequence was as follows: (1) EDTA group (n=10) : 5 ml of 17% EDTA for 1 minute followed by 5 ml of 2.5% NaOCl for 1 minute. (2) Maleic acid group (n=10) : 5 ml of 7% maleic acid for 1 minute followed by 5 ml of 2.5% NaOCl for 1 minute. (3) Phosphoric acid group (n=10) : 5 ml of 5% phosphoric acid for 1 minute followed by 5 ml of 2.5% NaOCl for 1 minute. (4) Control group (n=5): 5 ml of 0.9% saline for 1 minute followed by 5 ml of 2.5% NaOCl for 1 minute. The root canals were finally irrigated with 5 ml of distilled water to remove any precipitate that might have formed. The canals were dried with absorbant points and cotton pellets were placed in the access o cavities. The teeth were stored at 37 C and 100% humidity in humidifier. Longitudinal grooves were prepared on the buccal and lingual surfaces of each root by using a diamond disc with coolant at a slow speed without penetrating the canal. The roots were then split into two halves using a chisel. The specimens were kept in 100% ethanol for 24 hours o to dehydrate. The samples were stored at 37 C until SEM analysis. 9

3 The samples were mounted on metallic stubs, gold sputtered using an ion sputter, and examined under scanning electron microscope for the presence or absence of the smear layer. Several photomicrographs were taken to observe the surface morphology at 2000x magnification of the canal wall at the coronal (10-12 mm from apex), middle (6-7 mm from apex), and apical (1-2 mm from apex) thirds of each specimen. The images were scored according to the following 16 criteria given by Torbinejad et al(2003). TABLE 1 : SCORING CRITERIA SCORE OBSERVATION 1 no smear layer ( no smear layer on the surface of The obtained data was subjected to statistical analysis using the SPSS 11.0 Program (SPSS Inc, Chicago, IL, USA). Non-parametric methods were used for statistical analysis. RESULTS: Mann-Whitney test showed that there was no significant difference between Maleic acid & Phosphoric acid at coronal, middle & apical third levels. There was no smear layer present and tubules were wide open. In Phosphoric acid treated specimens dentinal erosion was present. There was significant difference between Maleic acid & EDTA as well as Phosphoric acid & EDTA( p-value < 0.05 ). In EDTA treated specimens, there was moderate smear layer present at all the levels of canals. In the control(saline) group, all the specimens were heavily smeared at all three levels. DISCUSSION : the root canal; all tubules were clean and open) 2 moderate smear layer ( no smear layer on the surface of root canal; but tubules contained debris) 3 heavy smear layer ( smear layer covered the root canal surface and tubules) The literature describes a variety of chemicals with broad range of concentrations and different [7] irrigation regimens to remove smear layer. In the present study, we compared the efficacy of 17% EDTA, 7% Maleic acid & 5% Phosphoric acid for the same purpose from the coronal, middle & apical thirds of the human root canal system. The results revealed that 7% Maleic acid had a better smear layer removal ability than 17% EDTA in all thirds of the canal. [15] Similar study done by Prabhu et al in 2003, Ballal et al in 2009 stated that there was no significant difference between 17% EDTA & 7% Maleic acid at coronal and middle thirds, while in apical thrid 7% Maleic acid is more efficient. In their study, apical preparation was done with 40 no. K-file (D0=0.40 mm) & 2% taper throughout the canal length. 27- guage bevelled needle (0.4mm outer diameter) was used for irrigation. Because of this closely matching diameter of apical preparation & irrigating needle there seems to be no space for the irrigating solutions to act in apical area. Moreover, the bevelled needle tends to extrude atleast some volume of solution beyond the apical foramen unavoidably, rather than being the full amount available to act in the apical third of the canal. It also cannot create upward turbulence for its maximum [17] cleansing effect as in case of side bore needles. In the present study, we have used Max-I Probe, 30 guage (0.3 mm) (Dentsply Maillefer, Ballaigues, Switzerland) for irrigation of root canals. The introduction of a slim irrigating needle with a safety tip & side vent to working length or 1 mm short of it is a promising approach to improve irrigant efficacy [17] in the apical third. The dispersal of irrigating solution through the side-vent in the cannula creates a unique upward turbulent motion, which thoroughly irrigates the root canal preparation & prevents solution and debris from being expressed through the apical foramen. The closed & rounded [18] end of probe reduces risk of periapical damage. When a 30-gauge needle is used, the apical preparation should be till ISO-size 40 to 50 to secure [17] proper rinsing of the apical area. Thus, in our study the apical part of canal preparation was performed up to ProTaper F5 (D0= 0.50 mm) & 5% taper. Many studies have provided a strong consensus that larger apical preparation produces a 10

4 Vora et al greater reduction in remaining bacteria and dentin debris as compared to smaller preparation [19,20].Hence, apical preparation size becomes an issue. Though the apical preparation was performed up to ISO size no. 50, EDTA was not able to remove smear layer effectively when compared with Maleic acid. This might be attributed to the increased surface tension of 17% EDTA ( N/m) when compared 5 to that of 7% maleic acid ( N/m). Seidberg & Schilder in 1974 showed that under neutral conditions most chelators have a ph under the neutral value. The exchange of calcium from the dentin by hydrogen results in a subsequent decrease in ph. Because acid is released, the efficiency of EDTA decreases, thus decreasing the [21] rate of demineralization. As Maleic acid is highly acidic, it has a better demineralizing effect within a shorter period of time. The results also revealed that 5% Phosphoric acid had a better smear layer removal ability than 17% EDTA in all thirds of the canal. The SEM photographs revealed that in addition to smear layer removal, 5% Phosphoric acid also exposed the collagen network of the peritubular [22] dentin around enlarged tubular openings. This suggests unwanted demineralization of dentin leading to decreased dentin microhardness. The results are in agreement with the study done by [23] Ayad et al in They tried the Phosphoric acid concentrations as low as 5% to as high as 32%. Although no study evaluating the cytotoxicity of Phosphoric acid is found in the literature, the use of higher concentration may carry a higher risk of cytotoxicity, especially when used in apical third of [7] the canal. So, we used 5% Phosphoric acid in the present study. The recommended amount of EDTA for the removal of smear layer varies from 3 to 20 ml per canal. We used 5 ml of final rinse in this study as proposed by Mello I et al in They showed that a final rinse with 5 ml of EDTA was as effective as 10 or 15 ml of [24] EDTA for the removal of the smear layer. that the exposure of radicular dentin to 17 % EDTA for more than 1-minute causes erosion of both peritubular and intertubular dentin and also reduces the dentin microhardness. Therefore 1 minute irrigation time was chosen for present study, which is in favour with studies done by Saleh AA etal [27] [28] in 1999, Niu W et al in 2005 & Crumpton et al in [29] Saline, which is used as an irrigant in the control group, was found to have no effect on the smear layer removal. This is in accordance with the study [30] done by Carvalho et al in Combination regimens are always preferred for maximum demineralizing efficiency based on the studies done by Goldman et al (1982), Yamada et al (1983), Baumgartner & Mader ( 1987), Bystrom & Sundqvist (1985).In our study Sodium hypochlorite was used along with EDTA, Maleic acid and Phosphoric acid. It is showed that the cleaning action and the antimicrobial effect are greater when these agents are used along with Sodium [14] hypochlorite. Within the limitations of this study, a 1-minute irrigation of 7% maleic acid followed by 2.5% NaOCl is an effective final irrigant for the removal of the smear layer from the root canal system in the apical third. G R A P H 1 : S C O R I N G C R I T E R I A F O R EXPERIMENTAL & CONTROL GROUPS [25] [26] Calt & Serper in 2002 & Ari et al in 2004 stated 11

5 FIGURE 1 : GROUP I ( EDTA ) CORONAL FIGURE 6 : GROUP II ( MALEIC ACID ) - APICAL FIGURE 2 : GROUP I ( EDTA ) MIDDLE FIGURE 7: GROUP III ( PHOSPHORIC ACID ) - CORONAL FIGURE 3 : GROUP I ( EDTA ) APICAL FIGURE 8: GROUP III ( PHOSPHORIC ACID ) - MIDDLE FIGURE 4 : GROUP II ( MALEIC ACID ) - CORONAL FIGURE 9: GROUP III ( PHOSPHORIC ACID ) - APICAL FIGURE 5 : GROUP II ( MALEIC ACID ) - MIDDLE FIGURE 10 : GROUP IV ( SALINE ) - CORONAL 12

6 Vora et al FIGURE 11 : GROUP IV ( SALINE ) - MIDDLE FIGURE 12 : GROUP IV ( SALINE ) - APICAL CONCLUSION: Final irrigation with 7% Maleic acid is more efficient than 17%EDTA in the removal of smear layer from the apical third of the root canal system, which is a crucial area for disinfection. 5% phosphoric acid gave similar results as 7% Maleic acid but it showed deleterious effects on root dentin. Thus, Maleic acid might be preferred over Phosphoric acid to achieve the desired objective. REFERENCES: 1. Yared GM, Bou Dagher F. Sealing ability of the vertical condensation with different root canal sealers. J Endod 1996;22: Wu MK, De Gee AJ, Wesselink PR. Leakage of AH26 and Ketac-Endo used with injected gutta-percha. J Endod 1997;23: Skinner R, Van Himel T. The sealing ability of injection-molded thermoplasticized guttapercha with and without the use of sealers. J Endod 1987;13: Çobankar FK, Adanir N, Belli S. Evaluation of the influence of smear layer on the apical and coronal sealing ability of two sealers. J Endod 2004;30: Ballal NV, Kandian S, Mala K, Bhat KS, Acharya S. Comparison of the efficacy of maleic acid and ethylenediaminetetraacetic acid in smear layer removal from instrumented human root canal: a scanning electron microscopic study. J Endod 2009;35: Torabinejad M, Handysides R, Khademi AA, et al. Clinical implications of the smear layer in endodontics: a review. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2002; Prado M, Gusman H, Gomes B P.F.A, Simao RA. Scanning Electron Microscopic Investigation of the Effectiveness of Phosphoric Acid in Smear Layer Removal When Compared with EDTA and Citric Acid. Journal of Endodontics 2011;37: Clark-Holke D, Drake D, Walton R, Rivera E, Guthmiller JM. Bacterial penetration through canals of endodontically treated teeth in the presence or absence of the smear layer. J Denty 2003; 31: Kokkas AB, Boutsioukis AC, Vassiliadis LP, Stavrianos CK. The influence of the smear layer on dentinal tubule penetration depth by three different root canal sealer: an in vitro study. J Endod 2004; 30: Cergneux M, Ciucchi B, Dietschi JM, Holz J. The influence of the smear layer on the sealing ability of canal obturation. Int Endod J 1987; 20: Kennedy WA, Walker WA Jr, Gough RW. Smear layer removal effects on apical leakage. J Endod 1986; 12: Taylor JK, Jeansonne BG, Lemon RR. Coronal leakage: effects of smear layer, obturation technique, and sealer. J Endod 1997; 23: Clifford J.Ruddle- Hydrodynamic Disinfection Tsunami Endodontics; International Dentistry Sa;2010:11:4: Hulsmann M, Heckendroff M, Lennon A. Chelating agents in root canal treatment: mode of action and indications for their use. Int Endod J 2003;36:

7 15. Prabhu SG, Rahim N, Bhat KS, et al. Comparison of removal of endodontic smear layer using sodium hypochlorite, EDTA and different concentrations of maleic acid a SEM study. Endodontology 2003;15: Torabinejad M, Khademi AA, Babagoli J et al. A new solution for the removal of the smear layer. J Endod 2003;29: Zehnder M, Dent M. Root canal Irrigants. J Endod 2006;32: Haapasalo M, Qian W, Irrigants & Intracanal medicaments. In : Ingle J, Bakland L, Baumgartner C. Ingle's Endodontics, 6th edition. BC Decker Inc, Hamilton,2008. Pg no : Kerekes K, Tronstad L. Morphometric observations on the root canals of human molars. J Endod 1977;3: Usman N, Baumgartner JC, Marshall JG. Influence of instrument size on root canal debridement. J Endod 2004;30: Seidberg B, Schilder H. An evaluation of EDTA in endodontics. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1974;37: Takeda FH, Harashima T, Kimura Y, et al. A comparative study of the removal of smear layer by three endodontic irrigants and two types of laser. Int Endod J 1999;32: Ayad MF. Effects of rotary instrumentation and different etchants on removal of smear layer o n h u m a n d e n t i n. J P r o s t h e t D e n t 2001;85: Mello I, Robazza CRC, Antoniazzi JH, et al. Influence of different volumes of EDTA for final rinse on smear layer removal. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008;106:e Calt S, Serper A. Time-dependent effects of EDTA on dentin structures. J Endod 2002;28: Ari H, Erdemir A, Belli S. Evaluation of the effect of endodontic irrigation solutions on the microhardness and the roughness of root canal dentin. J Endod 2004;30: Saleh AA, Ettman WM. Effect of endodontic irrigation solutions on microhardness of root canal dentin. J Dent 1999;27: Niu W, Yoshioka T, Kobayashi C, Suda H. A scanning electron microscopic study of dentianl erosion by final irrigation with EDTA and NaOCl solutions. Int Endod J 2002;35: Crumpton BJ, Goodell GG, McClanahan SB. Effects on smear layer and debris removal with varying volumes of 17% REDTA after rotary instrumentation. J Endod 2005;31: Carvalho AS, Camargo CHR, Valera MC, et al. Smear layer removal by auxiliary chemical substances in biomechanical preparation: a scanning electron microscope study. J Endod 2008;34: Source of Support : Conflict of Interest : Date of Submission : Review Completed : NIL NOT DECLARED