الفهرس 
Endodontic mishapsOnly 14 pages are availabe for public view
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Abstract
Abstract
Keywords: Dentinal cracks, Root surface, Rotary preparation, Nickel Titanium,
ProTaper Next,2 Shape, Race.
Purpose: Evaluating and comparing dentinal cracks in root canal surface after root
canal biomechanical preparation using different rotary files system.
Materials and Methods: Forty freshly extracted human single canal mandibular
premolars with straight mature fully developed roots were used in this study. Teeth
were decoronated perpendicular to the long axis of the tooth leaving roots
approximately (12±1mm) and were positioned centrally and fixed in a mold using
acrylic resin blocks. Roots were randomly divided into 4 main groups according to
the Nickel Titanium (Ni-Ti) rotary file system being used in root canal preparation
(10 teeth for each group)
group I: Control group roots were left unprepared. group II: Canals were
prepared by using Ni-Ti rotary 2 shape system up to TS2 file (#25/0.06). Group
III: Canals were prepared by using Ni-Ti rotary ProTaper Next system up to X2
file (#25/0.06). group IV: Canals were prepared by using Ni-Ti rotary Race
system up to file (#25/0.06). Each root was sectioned horizontally by using Isomet
saw to give three sections: coronal, middle and apical with a total of 120 sections.
Each section was observed by Stereomicroscope to detect dentinal cracks.
Representative samples from each group were observed by scanning electron
microscope (SEM) to confirm the data from stereomicroscope.
Results: There is more dentinal cracks in the ProTaper Next group than 2 Shape
,Race and control groups as there was statistically significant difference present
(P<0.05).There were no Statistically significant difference between the apical
,middle and coronal sections. (P=0.536).