الفهرس 
ContentsOnly 14 pages are availabe for public view
 |  | from | 104 |  |  |
| | | from | 104 | | |
Abstract
Aim of the study:The purpose of this study was to evaluate and compare the shaping characteristic of different rotary NiTi systems (Hyflex EDM one file, Reciproc R25, Wave one primary) in extracted human teeth using cone beam computed tomography scanning. Materials and methods: Fourty five mesiobuccal canals of mandibular molars with angle of curvatures between 25-45 degrees, were randomly divided into 3 experimental groups (n = 15), according to the NiTi rotary system used, Hyflex EDM,Reciproc R25 and WaveOne Canals were scanned before and after instrumentation by using CBCT scanner to evaluate canal transportation and centering ratio at 3, 6 and 9 mm from the apex. Data were statistically analyzed and the significance level was set at P< .05. Results : At 3 mm from the apex, Hyflex EDM showed significantly the lowest canal transportation value and the highest centring ability when compared with Reciproc R25 and WaveOne systems. and no significant difference in the amount of transportation and centering ability between Reciproc R25 and WaveOne systems. At the level of 6 mm from the apex, Hyflex EDM showed significantly the lowest value of canal transportation and highest centring ability when compared with other systems,andReciproc R25 showed significantly less canal transportation and more centering ability when compared with WaveOne. At the level of 9 mm from the apex there were no significant difference in the amout of transportation and centering ability between the three groups. Conclusion :Within the limitation of this study, least canal transportation and highest centering ability was produced by Hyflex EDM system with evenly dentin removal from canal walls better than Reciproc R25 and WaveOne instruments at the 3 mm from the apex,and at 6 mm from the apex, Hyflex EDM showed the least canal transportation and the best centering ability followed by reciproc R25 then followed by WaveOne,and at 9 mm from the apex there were no difference between the three file systems in canal transportation and centering ability.