Volume : 1
Issue : 1
Online ISSN : 2581-8988
Print ISSN : 2581-9534
Article First Page : 9
Article End Page : 12
Aim: NiTi rotary files have gained popularity over recent years due to their inherent advantages. Despite their increased use worldwide the unexpected fatigue after extended clinical life span is one of the major shortcomings with these file systems. So the aim of this study was to evaluate the fracture resistance of Ni-Ti file (One Shape) in continuous and reciprocating motion in curved mesial canals of human permanent mandibular molars.
Materials and Method: Forty human permanent mandibular molars with mature apices were selected with an inclusion and exclusion criteria. After the access was prepared and working length determined and gylde path was achieved the teeth were divided into two groups.
Group A (Continuous Motion): Complete cleaning and shaping was done with One Shape® (Micro Mega, France) file in continuous motion. The file was re used in another tooth, until the file fractured. This was repeated until all the 5 files were fractured in the group.
Group B (Reciprocating Motion): Complete cleaning and shaping was done with One Shape® (Micro Mega, France) file in reciprocating motion. The file was re used in another tooth, until the file got separated / distorted. This was repeated until all the 5 files were separated in the group. The time needed for the complete preparation was also noted for both the groups. The groups were then observed under SEM.
Results: The Independent-Samples T Test procedure compares means for two groups of cases. Based on the results of the study it is not advisable to use this file in multiple teeth with any motion (CW/CCW). However it showed that use of continuous motion was safer and faster than reciprocating motion.
Conclusion: One Shape® file can be safely used to the working length of curved canals at least 5 times under continuous motion without any help of other files. While One Shape® can be used safely in reciprocating motion in at least 3 canals.
Keywords: Continuous motion, One shape file system, Reciprocating motion