Primary root canal treatment is a defined treatment with well-established reports of high clinical and radiographic success rates. Failure of root canal treatment leads to indication for clinical mediation. One of the most common causes of failure is a complex root anatomy that has not been adequately cleaned or shaped such that microbial flora remains in the apical sections of the root canals. Failure to completely remove the previous filling can make proper disinfection difficult by limiting the access of antimicrobial agents to some areas of the root canal system. Debris may cover areas where residual infection occurs. If bacteria remain in the apical canal, the risk of periradicular inflammation increases. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an Original Essay One of the most important considerations, which influences the outcome of retreatment, is the complete removal of the root canal filling material. The efficiency and accuracy of reprocessing instruments to remove the filling material are important factors in the success of the treatment. The biggest challenge for these retreatment instruments is to exactly follow the anatomy of the canal to remove all root canal filling material. Several techniques have been proposed to remove filling materials, most of the newer ones using nickel-titanium (NiTi) rotaries. Alternatively, some authors have proposed removing previous filling material with alternative single-instrument systems originally designed for root canal preparation. In this case, the removal of the filling is performed simultaneously with the instrumentation. Further widening could further reduce the amount of remaining fill. However, extensive widening is associated with the risk of canal carriage and this risk must be carefully weighed against the additional benefit.11 Regardless of the retreatment technique, numerous studies have shown that complete removal of root canal fillings is not commonly achieved, 12 in particular in the apical portion of the root canals. Therefore, additional approaches have been suggested to improve complete removal of filler material. A new NiTi finishing instrument has recently been developed with the aim of improving root canal cleaning: the XP-endo Finisher R (FKG Dentaire, La Chaux-de-Fonds, Switzerland), which is a non-conical measuring instrument n. 30 made with NiTi MaxWire alloy (Martensite-Austenite Electropolish FleX, FKG Dentaire). Due to this special alloy, this instrument takes on a straight shape in its martensitic phase, which is achieved below 30° C. However, when inserted into the canal at body temperature, it transitions to the austenitic phase in which the instrument takes on a spoon-like shape. shape in the last 10 mm with a depth of approximately 1.5 mm. During rotation, this instrument reaches a natural diameter of 3 mm in the last 10 mm. According to the manufacturer, when you squeeze the tip of the instrument, the bulb can expand up to 6 mm; when the bulb is compressed, the tip will expand up to 6 mm. Therefore, when the XP-endo instrument is moved up and down 7-8 mm within the canal, the natural constrictions and expansions in the canal will alternately cause the bulb and tip to expand and contract. This causes the instrument to scrape the canal walls and cause turbulence in the irrigating solution. The XP-endo Finisher R instrument has the potential to be applied as an adjunctive procedure in retreatment cases to maximize the.