Methodology
fractures, calcification
SMEAR LAYER
A total of 64 maxillary central incisor teeth with fully formed roots and closed apices were selected for his study. These teeth were extracted from individuals within the age group of 18–45 years for periodontal or orthodontic reasons. Prior to inclusion, the teeth were examined under a stereomicroscope, and any teeth with cracks or fractures were excluded. Only teeth without root canal calcification or resorption and with a minimum root length of 15 mm were included. Soft and hard tissue accumulations on the teeth were removed using a curette, and the teeth were stored in distilled water at room temperature until use. The teeth were decoronated using a slow-speed diamond saw with liquid cooling to obtain standardized root lengths of 15 mm. A size 10 K-type file was inserted into the root canal, and the working length was determined to be 1 mm shorter than the length visible at the apical foramen. The samples were randomly divided into two groups according to the concentration of NaOCI to be used during root canal instrumentation (Distribution of groupsAll samples were shaped up to X4 using the Protaper Next rotary file system(DenstplyMaillefer, Baillagues,Switzerland) and the X-Smart Plus (Dentsply Maillefer, Ballaigues, Switzerland) endodontic motor. Irrigation was conducted using 1 mL of either 2.5% or 5.25% NaOCI solution (Imicrly, Konya, Turkey) with a 31G side-vented needle during instrument change. Following instrumentation, the root canals were irrigated with 5 mL of 17% EDTA solution (ImidentTM Med., Konya, Turkey) for 1 min to eliminate the smear layer. No additional solution was utilized between the NaOCI irrigation and the subsequent EDTA irrigation. Afterwards, the samples were randomly divided into four subgroups based on the method of final irrigation activation (