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Year : 2018  |  Volume : 8  |  Issue : 1  |  Page : 34-38

Comparative evaluation of postobturation apical seal following intracanal irrigation with maleic acid or a combination of chlorhexidine and ethylenediaminetetraacetic acid: An in vitro study

1 Department of Conservative Dentistry and Endodontics, Manipal College of Dental Sciences, Manipal University, Manipal, Karnataka, India
2 Department of Biochemistry, Kasturba Medical College, Manipal University, Manipal, Karnataka, India

Date of Web Publication10-Jan-2018

Correspondence Address:
Dr. Tina Puthen Purayil
Department of Conservative Dentistry and Endodontics, Manipal College of Dental Sciences, Manipal University, Manipal - 576 104, Karnataka
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/sej.sej_55_17

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Aim: The aim of this study is to evaluate postobturation apical seal following intracanal irrigation with maleic acid (MA) or a combination of chlorhexidine (CHX) and ethylenediaminetetraacetic acid (EDTA).
Materials and Methods: Thirty single-rooted human premolar teeth were decoronated and subjected to root canal instrumentation. Based on the final irrigating regimen, samples were divided into 3 groups: Group 1- Irritrol (EDTA + CHX), Group 2–7% MA, and Group 3–0.9% Saline (control). The samples were then obturated and placed in humidor for 7 days. Specimens were subjected to microleakage analysis at 24 h, 7 days, and 14 days using glucose filtration technique. The samples were then analyzed with a glucose kit in a calorimeter at 500 nm wavelength. Data were analyzed using one-way ANOVA, post hoc Tukey's test, post hoc Games–Howell test, and Bonferroni test.
Results: There were overall significant differences in the mean scores among all the three groups (P < 0.001). Saline group demonstrated a significant higher leakage than that of MA followed by Irritrol. 14th day had significantly higher leakage when compared to 7th day with least being at 24 h.
Conclusion: Final irrigation with Irritrol improved the postobturation apical seal when compared to 7% MA.

Keywords: Apical seal, chlorhexidine, ethylenediaminetetraacetic acid, MA, microleakage

How to cite this article:
Agrawal R, Purayil TP, Ballal NV, Belle VS. Comparative evaluation of postobturation apical seal following intracanal irrigation with maleic acid or a combination of chlorhexidine and ethylenediaminetetraacetic acid: An in vitro study. Saudi Endod J 2018;8:34-8

How to cite this URL:
Agrawal R, Purayil TP, Ballal NV, Belle VS. Comparative evaluation of postobturation apical seal following intracanal irrigation with maleic acid or a combination of chlorhexidine and ethylenediaminetetraacetic acid: An in vitro study. Saudi Endod J [serial online] 2018 [cited 2023 Feb 3];8:34-8. Available from: https://www.saudiendodj.com/text.asp?2018/8/1/34/222761

  Introduction Top

The goal of endodontic therapy is to clean and shape the root canal system and to achieve an apical seal gained by a 3-dimensional obturation. This seal should prevent the percolation of any oral fluids between the intraradicular space and periradicular tissues.[1] Apical microleakage has been commonly attributed for the failures of endodontic treatment.[2] Various factors such as different techniques of root canal filling, smear layer, and physical and chemical properties of sealers have been found responsible for the same.[2] The smear layer is an amorphous irregular layer which consists of inorganic debris along with organic materials such as pulp tissue, necrotic debris, microorganisms, and their metabolic products and odontoblastic process.[3],[4] It compromises the formation of a satisfactory seal by forming a barrier between filling materials and the canal wall.[5] Hence, root canal filling materials should be applied to a surface which is devoid of smear layer to maximize the infiltration of obturating material into the dentinal tubules and reducing microleakage.[6]

In the past, various irrigants have been used for removing the smear layer-like citric acid, mixture of tetracycline isomer, citric acid and a detergent-Tween-80 (MTAD), ethylenediaminetetraacetic acid (EDTA), etidronic acid, chlorhexidine (CHX), and maleic acid (MA).[7],[8],[9],[10] Combination of NaOCl and EDTA is routinely used to remove smear layer.[11],[12] However, it has been reported that 17% EDTA is not efficient in removing the smear layer especially in the apical one-third of the root canal system [10] and is also considered to be cytotoxic.[13] MA is a mild organic acid which is used as an acid conditioner in adhesive dentistry due to its etching action.[14] Ballal et al.[15] in his study found that the final irrigation of the root canal system showed better efficacy with 7% MA in removing the smear layer when compared with 17% EDTA from the apical one-third.

Recently, a novel irrigant, Irritrol has been introduced which consists of CHX, EDTA, and a proprietary blend of surfactants. CHX allows for disinfection and EDTA being a chelating agent, removes the inorganic materials. According to the manufacturer, it not only eliminates the need for separate step irrigation of EDTA and CHX but also removes the smear layer less aggressively as compared to the conventional irrigants, hence, causing less demineralization of the dentin. In addition, green color of the irrigant ensures easy identification during the irrigation procedure. Till date, there are no studies reported on the effect of Irritrol and MA on the postobturation apical seal. Hence, the aim of the present study was to evaluate the postobturation apical seal after irrigating the canal with 7% MA and Irritrol using glucose filtration method.

  Materials and Methods Top

Institutional review board (IEC 724/2016) gave the ethical clearance. Freshly extracted thirty human, straight, and single-rooted, premolars were selected. The presence of completely formed apex, absence of any resorption, and single canal were verified using radiographs. Teeth with carious lesions, fractured/restored or cracked teeth, teeth with developmental defect, or dilaceration were not included. Ultrasonic scalers were used to clean the outer surface of the teeth followed by storage in 0.2% solution of sodium azide (Sigma Chemical Co, St. Louis, MO) at 4°C until the experiment. A diamond disk (Horico, Germany) of high speed was used to decoronate the tooth in the presence of a cooling device, and the length of the root was standardized to 15 mm. A 10 K no. file (Mani Inc, Tochigi Ken, Japan) was used to determine the working length until it appeared at the apex (observed under magnifying loupes) and 1 mm was subtracted from this point. Canals were prepared to size F3 using rotary Protaper files (Dentsply Maillefer, Ballaigues, Switzerland). 2.5% NaOCl (KMC Pharmacy, Manipal, Karnataka, India) solution (5 ml) was used to irrigate the canals after change of each instrument for 1 min.

According to the final irrigation protocol, teeth were then randomly divided into 3 groups (n = 10). Group 1: 5 mL of Irritrol (Essential Dental Systems, U. S. A) for 1 min, Group 2: 5 mL of 7% MA (KMC Pharmacy, Manipal, India) for 1 min, and Group 3: 5 mL of 0.9% Saline (control) for 1 min. 27-gauge Monoject needle (Ultradent Products Inc., South Jordan, UT, USA) was used to irrigate the canals. The needle was introduced into the canal within 1–2 mm of the working length. To remove any precipitate, 5 mL of distilled water was used to irrigate the canals finally. After drying the canals with sterile paper points (Dentsply-Maillefer, Ballaigues, Switzerland), obturation was done using F3 gutta-percha points (Dentsply-Maillefer) and AH plus (Dentsply, Konstanz, Germany) root canal sealer using single-cone obturation technique. To determine the apical extent, density, and homogeneity of the root canal filling, mesiodistal, and buccolingual radiographs were taken. Fuji II glass ionomer cement [GC Corporation, Tokyo, Japan] was then used to seal the root canal orifices followed by placing it in an air humidor (Classic scientific, Boisar, Maharashtra, India) at 37°C for 7 days so that sealer could set completely. Then, the teeth were dried, and nail varnish was used to coat it except 2–3 mm in the apical one-third.

Preparation of specimen for glucose filtration

A modified plastic dropper was taken. At one end, it was glued to the resected coronal part of each root, and the other was attached to the glass tube of 15 cm using cyanoacrylate glue. Sticky wax was used to prevent leakage at these connections. A sterile 5 ml glass-beaker containing 0.2% NaN3 was kept under the assembly and covered with paraffin sheet. 1 mol/L glucose solution (pH = 7.0) whose viscosity was 1.18 × 10−3 Pas at 37°C and density 1.09 × 103 g/L density was used as a tracer for the study. A volume of 5 ml of the glucose solution with 0.2% NaN3 solution was added into the modified dropper through the glass tube until the difference between the upper level of the solution and root canal filling was 14 cm creating a hydrostatic pressure of 1.5 kPa (15 cm H2O). The glucose that leaked through the canal was finally collected in the glass beaker.[16]

Measurement of microleakage

A micropipette at 24 h, 7 days, and 14 days was used to draw a 100 μL of solution from the glass beaker following which 1 ml of constant volume was maintained by adding the same amount of fresh 0.2% NaN3 into the glass beaker. Analysis of the samples was done using a glucose kit in a calorimeter at 500 nm wavelength. To avoid any bias, double-blinded independent evaluators determined the concentration of glucose. The results of leakage were obtained as mmol/L in all the groups from the respective optical density observed in a colorimeter, and the results were statistically analyzed.

Statistical analysis

Data were analyzed with SPSS software version 18. Statistical analysis for inter-group comparison was done using one-way ANOVA, post hoc Tukey's test, and post hoc Games-Howell test and that of intragroup comparison was done using Bonferroni test. P < 0.05 was considered statistically significant.

  Results Top

[Table 1] demonstrates the mean values of postobturation leakage between the experimental groups. There were overall significant differences in the mean scores among all the three groups (P < 0.001). Post hoc test showed that Group 3 (Saline) had significantly higher leakage than Group 2 (MA) and Group 1 (Irritrol). When Irritrol was compared with MA, the former showed less leakage. It was also seen that the leakage increased with increase in number of days. 14th day had significantly more leakage followed by 7th day with least leakage being at 24 h-irrespective of all the 3 experimental groups.
Table 1: Mean values of microleakage at different time intervals

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  Discussion Top

The root canal filling material is said to be efficient when it inhibits microorganisms and body fluids from seeping into the space of root canal system. Microleakage results in the presence of fluid-filled space due to lack of adhesion of obturation materials to the root canal dentin. This may be attributed to the presence of smear layer. Various studies have demonstrated the effect of different irrigating solutions on the sealing ability of root canal obturation. In a study by Bodrumlu et al.,[17] it was shown that MTAD had better sealing ability when compared to NaOCl and CHX. Ballal et al.[18] demonstrated that 7% MA showed better post obturation apical seal when compared to 17% EDTA. On the contrary, Ozgur et al.[19] showed that MA resulted in higher microleakage values when compared with EDTA as final irrigant. The difference in the results between various studies may be attributed to the diversity of microleakage measurement methods, smear layer removing abilities of irrigants, and the type of sealers used.[18],[19]

In this study, the postobturation apical seal after irrigating the canal with 7% MA, and Irritrol was compared. Microleakage could be because of lack of adhesion of obturation materials to the root canal dentin. Results of the present study revealed that, MA showed more leakage as compared to Irritrol at all the time intervals. This might be attributed to the surfactant present in Irritrol which would have reduced its surface tension leading to better removal of smear layer thus causing less microleakage. In addition, saline (control group) showed the maximum apical leakage when used as a final irrigant depicting that it does not affect smear layer, which might have interfered with adhesion of obturation material to root canal walls, leading to maximum microleakage.[20]

Various methods such as dye,[21] radioisotope,[22] and bacteria [23] have been used to assess apical leakage. However, these methods possess some disadvantages. Dye penetration require sectioning of the sample and also, penetration of dye is prevented due to the air inside the root canal.[24],[25] Variation is seen in bacterial leakage studies because of different species of bacteria used.[26] In addition, radioisotope leakage studies have disadvantage of radiation hazard.[27] The setup for the glucose filtration model was chosen in the present study because it is inexpensive and relatively simpler and feasible to carry out.

In the current study, quantitative analysis of the microleakage was done by determination of the concentration of glucose that leaked through the canal into the glass beaker.[28],[29] Glucose relates the condition clinically better when compared to other tracers used in apical leakage studies. The rationale behind this is its smaller molecular size and a source of nutrition for bacteria.[30],[31] Hence, if it could enter the root canal system from oral cavity, it could create a favorable environment for the bacteria that might have survived after root canal treatment, to further grow and hence potentially cause periapical inflammation.

When compared with copper or ferricyanide methods, the enzymatic glucose oxidase method provided the higher degree of specificity and sensitivity.[32] This was the reason it was chosen in the study to evaluate the concentration of glucose. In this method, enzyme glucose oxidase oxidizes glucose to form gluconic acid and hydrogen peroxide in an aerobic environment. Thus hydrogen peroxide formed lead to the oxidation of a chromogenic oxygen acceptor (4-aminoantipyrine and phenol) in the presence of a peroxidase enzyme, hence forming oxidized chromogen which is a red product. In the first reaction, the amount of glucose present is proportional to the oxidized chromogen. This model was able to measure the amount of microleakage continuously with time in correlation with the combined value of glucose leaked. In addition, low pressure in the coronal aspect eliminated entrapped air or fluid leading to high sensitivity.[28]

Various observation periods, such as 1 week, 2 weeks, or longer, have been used to evaluate the microleakage of root canal fillings in the past. Because leakage increases with time irrespective of the technique, a 2-week period was considered to be appropriate to make a comparison in the present study.[33],[34],[35]

  Conclusion Top

Within the limitations of the present study, it can be concluded that Irritrol was more effective in improving the postobturation apical seal compared to 7% MA when used as a final irrigant.

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Conflicts of interest

There are no conflicts of interest.

  References Top

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