European Journal of Cardiovascular Medicine

The removal of the smear layer during endodontic treatments is critical to the success of root canal therapy. The smear layer is composed of both organic and inorganic materials as a result of instrumentation, which may house bacteria and impede the penetration of drugs and irrigants [1]. The root canal system's disinfection and the sealing of root canal fillings are both significantly enhanced by removing the smear layer. Among the various irrigants used to eliminate smear layers, triton irrigation solution has proven to be a good choice [2]. Triton is a non-ionic surfactant that reduces surface tension of solutions, perhaps improving irrigant penetration and efficacy in the complex design of root canal systems [3]. This characteristic suggests that employing Triton irrigation solution in conjunction with conventional irrigants alone may enhance the removal of the smear layer more successfully [4].

By comparing Triton irrigation solution to other widely used irrigants like sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA), one may determine how successful Triton irrigation solution is at removing the smear layer [5,6]. We'll talk about Triton's practical application in endodontic therapy, as well as its mechanisms of action and new study findings [7]. Dental professionals who are aware of the advantages and disadvantages of Triton irrigation solution can make well-informed judgements and maximise the results of the root canal procedure [8].

Sample Selection and Preparation

The efficiency of Triton irrigation solution in removing smear layers during endodontic treatments was to be compared with other widely used irrigants, such as sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA), in a randomised controlled trial.

Forty mandibular premolars from patients in the 25–35 age range were collected. The teeth were selected based on the following criteria: all roots had to be free of caries; any apparent cracks had to be examined; the radiographic view had to be utilised to confirm the history of any endodontic therapy; and the canals had to be calcified. The teeth include a single, straight canal and fully developed apices. After the teeth were extracted, any associated hard or soft components were cleaned, and the teeth were incubated for a full day at 37°C in a 0.1% thymol solution before being preserved in regular saline to preserve moisture content [9].

The samples were held in place using a bench vice. The crowns were then cut transversally with a double-faced diamond disc at a high speed while utilising water coolant to achieve a 14 mm root length. The working length (WL) was verified using the #10 K file. Then, the file was inserted into the canal until the foramen was reached by the tip. The anatomical apex (13 mm) was 1 mm away from where the WL was constructed. Roots that initially allowed for size #20 instruments were chosen. The samples were sorted into four groups, each with ten members, according to the kind of irrigation solution that was applied: 5.25% NaOCl + 0.5% CNP in Group II, 5.25% NaOCl + 17% EDTA in Group III, and Triton all-in-one irrigant in Group IV Distilled water (control group).

Following the dissolution of 0.5 g of CNP powder (EPRUI, China) in 100 ml of 1% (v/v) acetic acid, the mixture was vigorously stirred for eight hours. The samples were sonicated for 40 minutes. Separately, 10 millilitres of distilled water were mixed with 0.1 gramme of sodium tripolyphosphate (STPP) and rapidly stirred for eight hours following a 40-minute sonication [10]. Next, the STPP solution was gradually added to the Chitosan solution (CS) dropwise until the ratio of CS: STPP reached 2:1. This was done using a 50 ml syringe at a drip rate of 15 drops per minute. This mixture was subjected to 40 minutes of sonication after 8 more hours of mixing (17). A NanoBrook 90Plus Particle Size Analyser (Brookhaven Instruments, USA) and dynamic light scattering were utilised to determine the size of CS-TPP. The CS suspensions had effective diameters of 84.4 nm.

The irrigation protocol was as follows:

Group I: Using about 5 ml (3–6 ml per root canal treatment), the canals were irrigated as needed during instrumentation, following the manufacturer's instructions. The last irrigation, which required 1.5 minutes of 1 millilitre of Triton, was followed by 5 millilitres of distilled water for washing.

Group II: Canals have been treated with 1 ml of 5.25% NaOCl, or roughly 5 ml, per three instrument strokes. Prior receiving their last irrigation, they were dried with an absorbent paper tip and washed with 5 ml of distilled water. For three minutes, 5 millilitres of 0.5% CNP were used for the final irrigation. Subsequently, the canals were irrigated with 5 millilitres of distilled water and dried using paper point #40.

Group III (17% EDTA): Prior to the last irrigation, the canals were cleaned with five millilitres of distilled water and dried with absorbent paper point size #40. For irrigation, a total of about 5 ml of 5.25% NaOCl were utilised. Paper point #40 was used for drying after the final irrigation, which involved five millilitres of 17% EDTA applied for three minutes and five millilitres of distilled water [12].

Group IV (distilled water): Following receiving 1 ml of distilled water each of the three instrument strokes, the canals got a final irrigation of 5 ml of distilled waters for 3 minutes, for a total volume that was about 5 ml.

The irrigation needle was inserted within 2 mm of the WL of the canal for irrigation [13].

Preparation of Sections for Viewing Under Scanning Electron Microscopy

Utilising a high-speed diamond bur, two parallel longitudinal grooves were created on the buccal and lingual regions of each root after the samples were removed from the mould [14]. The opening was sealed with a tiny cotton plug, and gutta-percha was inserted inside the canal to assess the depth of the groove and prevent bur penetration, which could have contaminated the canals with sectioning-related debris [15]. Next, as illustrated in Figure 1, the root was divided in half lengthwise along the channels using a chisel.

Figure 1. Splitting of the tooth, (a) Parallel longitudinal grooves on the buccal and lingual aspects of each root were made by using a high-speed diamond bur under water-cooling. (b) A chisel separates the root into two parts longitudinally along the grooves

The chosen samples (half sections of 180° or less) were examined at three distinct levels (2.5, 6, and 10 mm from the root apex) using a scanning electron microscope. Every picture captured at a magnification of 3000× was examined by two examiners who were blindfolded and calibrated. The correlation between the two examiners was assessed using the Kappa agreement test (kappa = 0.75). The degree of smear layer removal was assessed using a 4-point scoring system based on the Hülsmann et al. [16] ratings:

Score 1: Completely open dentinal tubules

Score 2: The dentinal tubules are open more than 50%.

Score 3: The dentinal tubules are open to a maximum of 50%.

Score 4: The smear layer almost entirely covers the dentinal tubules.

Statistical Analysis

The statistical study was conducted using IBM Armonk, New York's SPSS 22.0. The Shapiro-Wilk test was used to confirm that the distribution was normal. The Mann Whitney U test and the Kruskal Wallis test were applied to the data analysis. We decided to set the significance criterion at (p≤0.05).

High agreement between the two examiners was found using kappa, with values of 0.8 or greater for each of the different categories as shown in (Table 1).

Table 1-Kappa test for reliability between two observers at all tested group

Table 2-Kruskal-Wallis Test for the scores of smear layer removal for four groups at three different levels

Mann-Whitney for pairwise comparisons between groups, the U test was employed. At the coronal, middle, and apical levels, the Triton irrigation solution showed considerably (p<0.05) lower mean smear layer clearance than the other experimental groups. At the coronal and middle levels of the root canal, CNP and EDTA both showed comparable chelating agent efficacy; however, apically, CNP outperformed EDTA by a substantial margin (p ≤0.05) (Figs. 2, 3).

Figure 2. Scanning electron microscope photographs at 3000× magnification showing root samples treated with Group I (Triton), Group II (0.5% CNP) and Group III (17% EDTA) at different levels (coronal, middle, and apical) of the root canal CNP: Chitosan nanoparticles, EDTA: Ethylenediaminetetraacetic acid

Figure 3. Scanning electron microscope photographs at 3000× magnification showing root samples treated with Group IV (distilled water) at different levels (coronal, middle, and apical levels) of the root canal.

A successful root canal surgery depends on efficient chemico-mechanical root canal area preparation [17]. But after shaping treatments, residual smear layers usually build up on the root's inner dentinal walls [18], which can lead to failure and irreversible contamination [19]. The investigation's findings demonstrated that no irrigation solution was able to completely eradicate the smear layer in any of the three root zones. This could be caused by the complex canal geometries, the limited impact of each irrigation solution, and the inability of irrigation solutions to reach every surface of the root canal [20].

Like other solutions, Triton's capacity to eliminate the smear is ascribed to the citric acid (CA) that is a component of its mixture. Apatite crystals and dentine remains can be dissolved by CA when it is utilised as a chelator.21 Recent research indicates that CA can have a synergistic action of manner interacting with other drugs.22,23 Furthermore, NaOCl solutions made by pH modifiers must maintain a persistent, high pH environment in order to have higher proteolytic effects. According to earlier studies, dentine debris, necrotic and inflammatory tissue, and inorganic smear layer components are anticipated to dissolve in NaoCl in much larger quantities.23,24 Benefits for the combination of surfactants, pH modifiers, CA, and NaOCl were demonstrated by the all-in-one design in Triton. Triton irrigation was less effective than CNP and EDTA at removing smear layers and shown a significant difference with both groups at the three levels. Therefore, the null hypothesis was rejected because there was a significant difference in smear layer removal between Triton and other solutions.

At the coronal and middle levels, there was no discernible difference between CNP and 17% EDTA, which is in line with other research.1,13,18 The CNP and 17% EDTA groups showed a notable difference in the apical level. Smear layer removal is difficult because of the reduction in root canal diameter at the apical third. Chitosan particles that are nanosized have the ability to quicken the irrigation solution's passage into the dentinal tubules, boosting the elimination of the smear layer.15 Chitosan is easily adsorbed to the root canal walls and carried deep into the dentinal tubules due to its hydrophilic character, which encourages close contact with dentine in the root canal.25 This outcome is in line with previous research that discovered CNP is more effective than 17% EDTA and citric acid at removing smear layers from the apical region.18 Since the chelating activity of the neutral EDTA solution is based on the removal of calcium from both the organic and inorganic components of dentine, such as water-soluble non-collagen proteins, which are present at lower concentrations in the apical area, the amount of EDTA decalcification is reduced, which could account for the lower capacity of EDTA for smear layer removal in the apical third. The efficacy of EDTA may also be diminished by dentine tubular sclerosis in the apical part of the root canal.26

Within the constraints of this investigation, it can be deduced that 0.5% CNP removes the smear layer more effectively at the apical root level than the other tested solutions, while Triton irrigation solution performs less well than 0.5% CNP and 17% EDTA at all root canal levels. In contrast, 17% EDTA removed the smear layer at the coronal and middle levels of the root canal just as effectively as 0.5% CNP.

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