Aim: To compare the effect on vertical fracture resistance of teeth instrumented with ProTaper Gold, MicroMega 2shape mini and Mani JIZAI rotary file systems.

Materials and Methods: 32 freshly extracted mandibular premolar teeth were selected, teeth were decoronated to maintain 14mm of standardized root length. The teeth were then randomly divided into 4 groups where group I served as the control group. Groups II, III and IV were instrumented with ProTaper Gold, MicroMega 2shape mini and Mani JIZAI rotary file systems respectively. After cleaning and shaping the prepared and unprepared teeth were embedded in auto-polymerizing acrylic blocks. The teeth were then subjected to a vertical load in universal testing machine at a cross-head speed of 1 mm/min until vertical root fracture occurred. The forces required to cause the fractures were then recorded. The data was normally distributed and was analysed using one-way ANOVA. A p-value ≤ 0.05 was considered to be as statistically significant.

Results: Teeth instrumented with Mani JIZAI rotary files showed more resistance to Vertical Root fracture.]