The long-term effectiveness of root canal therapy is dependent on thorough root canal disinfection and sterilisation, followed by the root canal system being sealed by filling it with material to insulate it from external stimuli. Apical sealing of high quality is essential for effective root canal therapy . Because of their low toxicity and hypoallergenicity, adhesive tips are widely used in clinical practice; however, they lack the adhesion to the dentin wall to fill irregular areas such as the apical zone  and must be used in conjunction with a fluid root canal sealer, making an ideal root canal sealer essential for reducing apical microleakage. The gold standard for assessing root canal sealing systems is AH Plus root canal sealer. In this study, AH Plus, GuttaFlow, and Resilon/Epiphany were utilized in this study to investigate the influence of different root canal filling materials on apical sealing. The results demonstrated that the Resilon/Epiphany filling system outperformed AH Plus and GuttaFlow for apical sealing in the short term (≤ 1 week). This might be owing to Resilon and Epiphany's excellent coupling, which interacts with the dentin wall to generate a thin mixed Resilon-Epiphany-dentin layer. Simultaneously, Epiphany sealers have minimal shrinkage and may stick to and enter the dentin tubules into the root canal wall, giving excellent sealing capabilities and successfully minimizing microleakage . However, some researchers  discovered no significant difference in the long-term apical seal between AH Plus and Resilon/Epiphany after 30 days, and some studies  even claimed that Resilon/Epiphany had a poorer long-term seal than AH Plus. Failure to adequately remove the dentin staining layer to expose the dentin tubules may impair Resilon/Epiphany bonding. Resilon/Epiphany is a resin-based root canal filling substance, and the material's polymerisation shrinkage influences long-term apical closure.
The GuttaFlow root canal filling system is a particulate adhesive (Diameter༜0.9 µ m) that sticks effectively to the dentin wall and expands by roughly 0.2% of its volume after curing, completing root canal filling and producing a good apical seal . However, there was no significant difference in the apical sealing effect of GuttaFlow and AH Plus in this Meta research, which may be due to differences in the manner the experiment was done, according to a review of the relevant literature. Root canal lumen closure . Furthermore, because GuttaFlow does not allow for lateral and vertical root canal filling pressurisation, voids are more prone to emerge once the canal is filled. These two considerations might explain the disparity in AH Plus and GuttaFlow apical closure outcomes.
The research presented in this publication differ greatly, and I believe this is due to the methodological execution of the tests on isolated teeth, such as sample selection, root canal preparation procedures, irrigation solution, and other aspects. To begin, the samples used for the study comprised a variety of tooth placements, such as anterior teeth and premolars, and while the root canal morphology was all single canal, the root canal morphology could not be similar, which had an effect on root canal closure. Second, the capacity of root canal preparation procedures to cut the canal wall varies, and root canal preparation with an excessive file size beyond the working length or an apical width larger than 1 mm may produce complications. Secondly, root canal preparation procedures range in their capacity to cut the canal wall, and excessive file size beyond the working length, or an apical width more than 1 mm, may cause damage to the apical foramen and is a risk factor for apical microleakage. Because an overly broad apical zone may result in impaired sealing of the root tip by the filling material and alter the final trial results, root canal preparation should not be over-prepared and should be confined to the working length of the root canal . The existence of a staining layer can impair the root canal filling material's adherence to the dentin wall. The removal of the stained layer using root canal washing solutions such as EDTA and NaCLO is favorable for root canal therapy success . However, it has been hypothesized  that when NaClO rinses are used for root canal irrigation, the fluid left on the root canal wall may have a detrimental effect on the binding between the filling material and the dentin, hence compromising the seal between the two. According to other investigations , the NaClO solution has essentially little influence on the binding between the sealer and the root canal wall. As a result, the influence of the washing solution on the sealing effect of the root canal filling material is not yet obvious.
Many techniques exist for identifying microleakage, including clear tooth staining to determine dye leakage length, spectrophotometry to determine dye filtration content, and fluid filtration to determine bubble displacement and other values . Different testing procedures are measured differently, and each has its own set of benefits and drawbacks, therefore they can also produce some mistake in the experimental results. For example, while the dye penetration approach is simple and straightforward, most studies only see microleakage in two dimensions from longitudinal or transverse sections of the root, and data gathering is up to the experimenter's discretion. The oral environment is diverse and varied, and apical microleakage is affected by temperature, flora, and other variables. The emphasis of research in analyzing root canal sealants is how to effectively perform microleakage detection, which is advantageous to improving the study's dependability.
This study had some limitations: it used a small quantity of literature, the implementer was single-blind, the specific random allocation technique was not specified, and the study's outcomes were restricted. Second, the study included literature with differing characteristics, such as preparation process and filling method, which might have influenced the Meta-analysis outcomes. To decrease the likelihood of experimental bias, future randomised controlled trials of isolated teeth must determine sample size, be randomised and blinded, and care for any confounding variables.