This study evaluated the influence of different access angles on the dynamic cyclic fatigue resistance of ProTaper Next (PTN), Twisted File Adaptive (TFA), and Reciproc Blue (REB) instruments that simulate body temperature in artificial canals. A total of 120 new instruments were used (n=40). PTN, TFA, and REB instruments were divided into four subgroups of 10 for insertion angles (0°, 10°, 20°, and 30°) in a 16-mm stainless steel artificial canal (60° curvature and 5 mm radius) using a customized device for a dynamic cyclic fatigue resistance test at 35°C (intracanal temperature). The number of cycles to fracture (NCF), time to fracture (TtF), and length of the fractured fragment were recorded, and the fractographical surfaces of the fractured fragment were observed using scanning electron microscopy. Data were analyzed with an analysis of variance (ANOVA) and the Krukal–Wallis H test and Tukey, Tamhane’s, and Bonferroni post hoc tests. The significance level was set at P<0.05. The NCF and TtF values of TFA were significantly higher than PTN and REB instruments (P<0.05). The increased inclined angle reduced the NCF and TtF (P<0.05). The maximum length of fractured fragments was observed at an angle of 20° for all instruments (P<0.05). Increased file inclination caused a reduction in the dynamic cyclic fatigue resistance of all instruments.