Evaluation of Cyclic Fatigue and Torsional Strength of Three Different Thermally Treated Reciprocating Nickel-Titanium Instruments

Objectives. This article's objective was to assess the reciprocating single-file systems Reciproc Blue 25.08 and Pro design R 25.06's cyclic and torsion fatigue resistance. The systems Reciproc Blue R25 (RB #25.08 taper), Prodesign R (PDR #25.06 taper), and WaveOne Gold (WOG #25.07 taper) (n = 20) were utilized to make sixty reciprocating instruments. The period to breakdown in an artificial stainless-steel canal with a 60° angle of curvature and a 5-mm radius was measured during cyclic fatigue resistance testing (n = 10). The torque and angle of rotation at failure of new instruments (n = 10) were assessed during the torsional test (ISO 3630-1) in the area 3 mm from the tip. Scanning electron microscopy was also used to view each fragment's shattered surface (SEM). In addition, a supplementary examination was performed to measure the cross- sectional area of each instrument 3 and 5 mm from the tip. The data were analyzed using one-way ANOVA and Tukey’s test, and the level of significance was set at 5%. Cycle Fatigue Resistance scores for PDR 25.06 were much higher (P 0.05). Both WOG 25.07 and RB 25.08 showed less resistance to fatigue (P 0.05). Based on the torsional analysis, PDR 25.06 had weaker torsional strength (P 0.05). No changes were found with RB 25.08 and WOG 25.07 (P > 0.05). PDR 25.06 showed higher angular rotation values than RB 25.08 and WOG 25.07. (P 0.05). Greater angular rotation was seen in both WOG 25.07 and RB 25.08. (P 0.05). The cross-sectional area analysis revealed that PDR 25.06 had the smallest cross-sectional areas at 3 and 5 mm from the tip (P 0.05). In comparison to RB 25.08 and WOG 25.07, PDR 25.06 had the highest cyclic fatigue resistance and angular rotation until fracture. Additionally, torsional strength was higher in RB 25.08 and WOG 25.07 than PDR 25.06. Clinical applicability in endodontic practise, reciprocating instruments that have undergone thermal treatment are used to prepare the root canals of canals that are curved and constrained; as a result, these instruments must exhibit high flexibility and suitable torsional strength to reduce the risk of instrument deformation.