Hand k files

The root canal instrumentation for the participants in this group was performed using the quarter-turn-and-pull motion. Stainless steel K-files were maneuvered in a sequence of #15/0.02, #20/0.02, #25/0.02, and #30/0.02 hand K-files (Mani, Tokyo, Japan). Between each file, the canal was irrigated by 2 mL of NaOCl. After the last file, the canal was irrigated by an additional 2 mL of NaOCl, and the final irrigation regime was performed.

Seventy-five teeth specimens were randomly divided (25 specimens/group) according to different root canal instrumentation:

Group-I (positive control group) (n = 25): teeth root canals were prepared using hand K-files (Mani Inc., Japan).

Group-II (experimental group) (n = 25): teeth root canals were prepared using A1-Kedo-S Square (Reeganz Dental Care Pvt. Ltd. India) rotary file.

Group-III (experimental group) (n = 25): teeth root canals were prepared using Fanta AF^™ Baby (Shanghai Fanta Dental Materials, SUNGO Certification Company Limited, London, England) rotary file.

The working length of the specimens was established using a size 10 K-file (Mani. Tochigi, Japan). Hand K-files (Mani) up to size 25, using 5.25% sodium hypochlorite (NaOCl) as the irrigant, were used for the achievement of the initial glidepath for all root canals. The specimens were then randomly divided into 3 groups based on the intended instrumentation protocol (n = 60): group 1: ProTaper NEXT (PTN, Dentsply Maillefer, Ballaigues, Switzerland), up to X4 size; group 2: WaveOne “large” file (WO, Dentsply Maillefer); group 3: Self-adjusting File, 2 mm diameter (SAF, ReDent, Raanana, Israel).
The instruments were used according to the manufacturers’ instructions, including irrigation protocols during instrumentation, as recommended by each of the manufacturers. During these procedures, 5.25% NaOCl was used as the irrigant. Irrigation during canal instrumentation in the ProTaper NEXT and WaveOne groups was performed using a syringe and a 31 G side-port needle (Ultradent, South Jordan, UT, USA). In the SAF group, irrigation was performed through the hollow file using a VATEA irrigation pump (ReDent), which is an integral part of the SAF system. The volume of irrigating solution and irrigation time during canal instrumentation were standardized to a total of 16 mL and 4 min, respectively, for all instrumentation methods.