Cyclic Fatigue Testing of New and Used Rotary Endodontic Files Fabricated from Two Different Alloys
Yasser Momtaz Mohamed Rashad El-Shafei;
Abstract
The aim of this study was to evaluate the cyclic fatigue resistance of new and used Hyflex CM fabricated from CM alloy and compares it to Race rotary files fabricated from traditional super-elastic Nickel-Titanium alloy.
A total of 80 rotary endodontic files, 40 files of each system were used in this study. Samples were divided into two groups, one for each system. Each system had four subgroups, new, used in 1 canal, used in 3 canals and used in 6 canals. Used files were allowed to shape Standard resin blocks with 60 degrees canal of curvature.
Cyclic fatigue testing was performed for new and used files in a previously designed cyclic fatigue testing device. Cyclic fatigue testing was performed by rotating instruments in an artificially constructed stainless steel canals with a 5 mm radius and 60̊ angle of curvature .The time to failure was recorded, and the total number of cycles to failure was calculated and compared for all samples. One way analysis of variance, two way analysis of variance (ANOVA) and t-student tests were done. In the present study P ≤ 0.05 was considered as the level of significance.
Fractured surfaces of broken instruments were also observed under scanning electron microscopy for any defect or deformations observed after testing.
Results:
Overall, there were significant differences in number of cycles to failure in rotary instruments made of different materials in all subgroups (new and used). For Hyflex CM group, there was a significant difference between new files and used files, but there was no significant difference between different subgroups of used files. For Race group there was no significant difference between new files and files used in 1 canal. But there was significant difference between new files and files used in 3 and 6 canals.
However, the results obtained from the test have no correlation with the expected clinical performance of the instruments. It might however, permit a reasonable comparison of the behavior of different instruments.
A total of 80 rotary endodontic files, 40 files of each system were used in this study. Samples were divided into two groups, one for each system. Each system had four subgroups, new, used in 1 canal, used in 3 canals and used in 6 canals. Used files were allowed to shape Standard resin blocks with 60 degrees canal of curvature.
Cyclic fatigue testing was performed for new and used files in a previously designed cyclic fatigue testing device. Cyclic fatigue testing was performed by rotating instruments in an artificially constructed stainless steel canals with a 5 mm radius and 60̊ angle of curvature .The time to failure was recorded, and the total number of cycles to failure was calculated and compared for all samples. One way analysis of variance, two way analysis of variance (ANOVA) and t-student tests were done. In the present study P ≤ 0.05 was considered as the level of significance.
Fractured surfaces of broken instruments were also observed under scanning electron microscopy for any defect or deformations observed after testing.
Results:
Overall, there were significant differences in number of cycles to failure in rotary instruments made of different materials in all subgroups (new and used). For Hyflex CM group, there was a significant difference between new files and used files, but there was no significant difference between different subgroups of used files. For Race group there was no significant difference between new files and files used in 1 canal. But there was significant difference between new files and files used in 3 and 6 canals.
However, the results obtained from the test have no correlation with the expected clinical performance of the instruments. It might however, permit a reasonable comparison of the behavior of different instruments.
Other data
| Title | Cyclic Fatigue Testing of New and Used Rotary Endodontic Files Fabricated from Two Different Alloys | Other Titles | احتبار الاجهاد الدورى لالات علاج الجذور الدوارة الجديدة و المستخدمة المصنعة من سبيكتين مختلفتين | Authors | Yasser Momtaz Mohamed Rashad El-Shafei | Issue Date | 2014 |
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