Ultrasonic retrieval of separated instruments was proven to be a highly successful procedure. However, its effects on root dentin are of major concern. Aim: To assess the influence of separated instruments alloy type on dentinal cracks development following ultrasonic retrieval in the presence of different intracanal lubricants. Methods: M-wire ProTaper Next files with tip size #25 and taper 0.6 (n=20), and EDM Neoniti files having the same size and taper (n=20) were fractured at 4mm from their tips in forty double-rooted moderately-curved upper premolars. A modified ultrasonic tip was used for their retrieval in presence of 17% EDTA solution or olive oil. Successfully retrieved samples had their roots horizontally sectioned, at 4mm and 6mm from the apex. Sections was examined under the SEM with different magnifications (60-300x) for cracks detection. Results: The majority of samples showed the development of dentinal cracks, with an incidence of 70% and 90% in ProTaper Next and Neoniti groups respectively in presence of EDTA, as opposed to 70% in Protaper Next and 80% in Neoniti in presence of olive oil, and with no statistically significant difference between the different alloys or intracanal. Conclusion: Separated instruments of different metallurgy show no effect on the incidence of dentinal cracks following ultrasonic retrieval. Lubricants of different viscosities fail to omit the development of cracks.