Purpose: This study aimed to evaluate the amount of apical extrusion produced by four contemporary rotary systems (XP-endo Rise, ProTaper Ultimate, TruNatomy, and One Curve). Because apical extrusion is associated with postoperative pain, inflammation, and delayed healing, identifying instrumentation techniques that minimize this phenomenon remains clinically important.
Methods: Eighty extracted human mandibular premolars with <20° curvature were decoronated and mounted on a modified Myers and Montgomery apparatus. Pre-weighed samples were randomly allocated into four groups (n=20) according to the system used. Extruded debris and irrigant were collected in pre-weighed Eppendorf tubes, and the difference between initial and final weights was recorded as the amount of apical extrusion.
Results: All systems produced apical extrusion. ProTaper Ultimate exhibited the highest mean (0.15±0.22×10-4
g), followed by TruNatomy (0.14±0.13×10-4 g), One Curve (0.11±0.08×10-4 g), and XP-endo Rise (0.08±0.05×10-4
g). Despite these numerical variations, no statistically significant difference was found among the groups (p=0.529).
Conclusion: All rotary systems resulted in apical extrusion, and none demonstrated superiority in minimizing it. These findings suggest that differences in design and kinematics alone may not substantially
influence extrusion behavior under standardized conditions.
Keywords: Endodontics, root canal preparation, tooth apex.