INTRODUCTION

One of the main reasons endodontic therapy fails is the microleakage of the treated teeth. An effective apical seal is vital to the endodontic treatment outcome. Because of the ancillary canals and variances in the root structure, accurately sealing the root canal is a challenging and delicate process. According to Kelmendi et al., improper and partial obturation account for 60% of endodontic failures [1]. According to other research, a poor seal is caused by insufficient flow of gutta-percha and its inability to bond to the walls of the dentin [2, 3]. Different techniques and materials have been studied to enhance and compare the sealing capabilities of root canal materials when new sealers are introduced to the market. The findings are conflicting; none of the sealers developed to date can fully satisfy the criteria for a flawless root canal seal [4-6].

Using computerized fluid filtration, Cobankara et al. investigated the apical sealing capabilities of Rocanal 2, RC sealers, AH Plus, and Sealapex; Sealapex offered a superior seal than the other sealers [7]. The fluid transfer via gutta percha in canals filled without or with RSA (Roekoseal Automix), EWT (Pulp Canal Sealer), and AH26 sealer was assessed in another investigation [5]. The samples without a sealer exhibited the greatest fluid movement rate (leakage) in comparison to the other groups, according to the results. A different investigation found that AH Plus had more micro-leakage than AH26 [4].

Pécora et al. investigated the dentine adhesion of root canal sealers by Er: YAG and found that AH Plus outperformed AH26 [8]. They also assessed the sealing performance of RSA, AH26, and AH Plus utilizing dye penetration in teeth filled with the Thermafill technique or lateral condensation. The teeth obturated using the Thermafill procedure without a sealer had the greatest dye penetration percentage, according to the results. Nevertheless, there was no discernible statistical variation seen in the average apical dye penetrations of the three distinct sealers [9].

It was observed that there was no discernible difference between RSA, Topseal, and Endometason's sealing performance when measured using the cross-section or clearing methods [10]. The adhesive properties of sealers based on epoxy resin are well-known [10-12]. Even when utilized only as the root canal filling, AH26, an epoxy-resin-based material, has excellent sealing ability [13]. This material's extended setting time and flowability prevent fracture development and rapid separation from the dentinal wall [14]. It has excellent texture compatibility, less than 0.5% shrinkage when entering the side channels, and the ability to stiffen in the presence of moisture [14, 15].

Unfortunately, the formaldehyde release and the lengthy (4-week) setting period are drawbacks [16]. It is said that AH Plus offers the benefits of AH 26 but with a quicker setting time and no formaldehyde release. In addition, compared to AH26, there seems to be less microleakage and more radiopaque [17, 18]. A new version of AH Plus called AH Plus Jet is supplied in mixing syringes that may be administered straight into canal orifices. Its usage is efficient and conducive to infection management because of the changeable syringe tip.

MATERIALS AND METHODS

A systematic literature review was conducted from 2000 to 2023 using Science Direct, Medline, and PubMed databases. AH 26, AH plus, root sealer, and microleakage were used as keywords. The PRISMA flowchart was utilized to describe the choice process of the reviewed articles (Figure 1).

Inclusion Criteria

• Randomized control and case-control studies
• Publication year between 2000 and 2023
• Published in English
• Study on humans (In vivo)

Exclusion Criteria

• Meta-analyses, Systematic reviews, Narrative reviews, or expert opinions
• The study is based on a survey
• Articles outside the specified time frame
• Articles whose language was not English
• In vitro

Bias Assessment Risk

Cochrane risk of bias assessment method was utilized to evaluate the quality of the included studies (Table 1).

RESULTS AND DISCUSSION

The study was conducted by Miletic et al., (2002) [10] to assess the amount of bacteria, either alone or in combination, that can penetrate gutta-percha-filled root canals and one or more root canal sealers, such as AH PlusandAH26. Eighty teeth were separated at random into two groups of forty teeth each, and either the AH26 or the AH Plus sealer was used to obturate the teeth with gutta-percha. Nail varnish was applied in two coats to the exterior surface of every root, with the apical 2 mm exception. The teeth were placed into sterile Schaedler broth-filled glass vials and suspended in Eppendorf plastic tubes. Twenty teeth filled with AH26 and twenty filled with AH Plus had their access cavities filled with Lactobacillus acidophilus, Prevotella melaninogenica, Streptococcus mitis, and Streptococcus mutans. In the experimental teeth, leakage occurred from day 14 to day 87. Of all the samples, 47% had leaks. Fungi and bacteria escaped from samples containing AH26 at a rate of 60% and bacteria from those with AH Plus at a rate of 50%. Between the sealers, there was no statistically significant variation in the amount of fungus and bacteria that penetrated.

De Moor et al., (2004) [11] conducted research to assess and contrast the sealability of root fillings in dental extractions utilizing three distinct obturation methods in combination with AH 26 and AH Plus. Procedure and supplies: 940 single-rooted teeth had their root canals prepared to use the crown-down/step-back method (with Flle-Eze and 2.5% NaOCI) before obturation with Thermafil or hybrid condensation and lateral condensation of the gutta-percha. At any point throughout the monitoring period, there were no statistically significant variations in apical leakage between the two sealer groups or between the AH Plus and AH 26 groups. At one day, one week, and two weeks, Thermafil dramatically increased coronal leakage in comparison to hybrid condensation for both AH Plus and AH 26. Thermafil was the only medication that showed more coronal leakage after one week as compared to lateral condensation for hybrid and AH 26 condensation for AH Plus.

The work done by Huang et al., (2000) [12] aimed to examine the lactate dehydrogenase (LDH) leakage from rat hepatocytes after in vitro root canal sealer treatment with AH26 and AH Plus. Male Sprague-Dawley rat hepatocytes were used to evaluate the cytotoxicity of AH26 and AH Plus. One-way ANOVA was used to quantify and assess the lactate dehydrogenase leakage values that were both dose- and time-dependent. The results demonstrated that rat hepatocytes are toxic to both AH26 and AH Plus. Rat hepatocytes were more sensitive to AH26 than AH Plus at low concentrations.

The research performed by Masoud et al., [13] compared three different root canal sealers' apical sealing capabilities. One hundred single-rooted teeth were utilized to assess the apical sealing capacity of three other root canal sealers: AH Plus, AH26, and ZOE (zinc-oxide eugenol). Every tooth's coronal portion was extracted, located around 2 mm above the cemento-enamel junction. Using hand files and Gates Glidden drills, the "Step-Back" method was used to instrument the root canals. 2.5% sodium hypochlorite was used as an irrigation fluid. The teeth were filled using gutta-percha points and test sealers using the cold lateral condensation method. The teeth were separated into three groups of thirty teeth each. Ten sets of teeth—five negative and five positive—were used as control groups. For three days, the teeth were submerged in 2% methylene blue. After that, the teeth were divided lengthwise, and their linear apical dye penetration was assessed. There were statistically significant (P<0.05) variations in leakage between ZOE [5.41mm; SD 0.274], AH Plus [3.64mm; SD 0.182], andAH26 [2.08mm; SD 0.215]. In the study's settings, there was some leakage experienced by all three sealers. Compared to ZOE, there was noticeably reduced leakage with both epoxy resin sealers (AH26, AH Plus). Compared to AH Plus, there was much reduced leakage with AH26.

Akhavan et al., (2011) [14] in his research, compared the sealing capabilities of three different kinds of resin-based sealers was the aim of this investigation. This research employed 87 human single-canal removed teeth in an experimental laboratory setting. Following root canal preparation and smear layer removal, the teeth were randomly assigned to 5 groups: 2 positive and negative control groups, 3 experimental groups, and 1 positive group. In the first experimental group, gutta-percha and AH26 sealer were used, followed by AH Plus Jet sealer and gutta-percha in the second group and gutta-percha and TGad seal sealer in the third group. Following that, the teeth were subjected to a 90-day microbial microleakage examination, during which each sample's daily turbidity occurrence time was noted. After a day, every sample in the positive control group had an infection. After ninety days, none of the models in the negative control group showed any signs of contamination. No statistically significant difference was observed among the three experimental groups in microbial leakage (P-value = 0.611).

The aim of the research conducted by Hasheminia et al., (2011) [15] was to evaluate the chemical and physical characteristics of Resil, an experimental endodontic resin sealer, in comparison to AH-26 and AH-Plus. From day 1 to day 30, all three groups had a considerable growth (P<0.05). The AH-Plus and experimental sealers had significantly different mean dimensional changes (P=0.020). The pH of the experimental sealer (Resil) two hours after mixing was substantially higher than AH-26 (P<0.001) and significantly lower than AH-Plus (P<0.001). The experimental sealer exhibited considerably greater antibacterial activity both before and after setting compared to the other two sealers (P<0.001).

The study executed by Ashraf et al., (2020) [16], compared and investigated the apical sealing capabilities of AH Plus Jet, AH Plus, and AH26, using the fluid filtration model.

Seventy single-rooted teeth were removed from the cemento-enamel junction for this experimental investigation. ProTaper rotary system and manual K-files were used to prepare the canals, while 17% EDTA and 5.25% NaOCl were used for irrigation. The control group consisted of ten teeth, split into five positive and five negative controls. After dividing into three groups of 20, the remaining samples were filled with gutta-percha using the lateral compression method.

One of the following: AH Plus Jet, AH Plus, or AH26was added to each sample group. On days two and thirty, the quantity of air bubble movement inside the capillary glass tube that was attached to the root was used to measure microleakage. Although AH Plus had the highest rate and AH Plus Jet had the lowest value of microleakage; statistically, the differences were not significant.

Rishi et al., [17] presented their study to compare AH plus, Apexit, Zinc Oxide Eugenol sealer, and AH 26's resistance to Enterococcus faecalis along obturated root canals with unsuccessful coronal sealing. Before being needed for the investigation, 52 excised human lower premolars were gathered, kept in saline, and then split into 5 groups of 10. Conventional methods were used for the root canal treatment, and distinct sealers were used for each group's obturation. Control group (group 0): teeth that were obturated without the use of a sealer. Groups 1 and 2 are AH Plus, Zinc Oxide Eugenol, and AH 26, while Group 4 is Apexit. As a consequence, ZOE (GROUP 1), APEXIT (GROUP 4), and AH PLUS (GROUP 2) were all outperformed by AH 26 (GROUP 3). Finally, AH 26 demonstrated the strongest defense against E. faecalis.

This research was set out by Schäfer et al., (2002) [18] to evaluate the seal achieved in both curved and straight root canals filled with Thermafil obturators or laterally compacted gutta-percha. Every method was combined with three distinct sealants (AH Plus, RSA Roeko Seal, and AH 26). There were 14 test groups, each consisting of 16 teeth, using Thermafil obturators in the sealer absence. As either positive or negative controls, sixty teeth were used. 142 removed teeth with straight root canals, and another 142 with curved root canals were included in the research. Up to size 40, all channels were expanded. Filling material extrusion was substantially higher in canals filled with Thermafil obturators than in canals filled with lateral compaction (p < 0.01). In both straight and curved canals, Thermafil without sealer demonstrated significantly higher dye penetration than all other groups (p < 0.05). Thermafil-obturated seals were comparable to lateral compaction in terms of dye penetration, provided a sealer was applied. The mean apical dye penetration for each of the three sealers did not vary statistically. For every group, the variations in dye penetration between curved and straight tubes were not statistically significant (p > 0.05).