88 human extracted mandibular premolars will be selected. Teeth will be sectioned below cementoenamel junction to get 13mm from the apex of root. Roots will then be standardized according to buccolingual and mesiodistal widths and will be examined for fracture and craze lines. The roots will then be randomly divided into 3 experimental groups and 1 control group (n=22). Group 1 will be instrumented with Hyflex EDM. Group 2 will be instrumented with F6 Sky Taper. Group 3 will be instrumented with One Shape and Group 4 will be negative control group in which no instrumentation will be done. After performing rotary instrumentation, roots will then be obturated with respective GP and sealer. Samples will then be exposed to vertical load utilizing Universal Testing Machine till fracture occur which will be recorded in Newton(N).
The purpose of this study is the assessment of vertical root fracture resistance of roots prepared with three different single endodontic rotary files in extracted human mandibular premolar roots.