Digital analysis of shaping ability and topographic changes in M and C wire rotary NiTi systems.

The primary outcome of this study intends to assess the Shaping ability and surface topographic changes What's new in the study is the use of AutoCAD program to assess the shaping ability of both instruments, after using them in a standerdized conditions to evalute the minor differences between the two different alloys used in each instrument. While the secondary outcome of this study is to evaluate the instruments after multiple uses under the SEM to detect any abberrations or deformetiesin the instruments to detect its points of strength and weaknesses. The study is planned for one year and it is not expected to be more than that according to the sample size and the availabilty of the tools needed for the trial.


Introduction
The main objective of endodontic treatment is to eliminate or minimize microorganisms in the root canal system while maintaining the original shape and path of the root canal. However, no instrument/technique can predictably eliminate all the microorganisms from the root canal system.
The cleaning efficacy of endodontic instruments significantly decreases at the apical third of root canals. Many root canals have curvatures, and endodontic instruments tend to return to their original straight position during instrumentation of curved canals. Dentinal wall thickness in root canals has a direct relationship with root resistance to lateral forces. Procedure -Teeth will be collected and immersed in 5.25% NaOCl solution for 15 min -The teeth will be stored in sterile saline until usage to preserve natural teeth hydration.
-Teeth will be radiographed using a conventional periapical radiograph -According to radiograph, only Mesiobuccal canals with a 25 o -40 o degree curvature according to Schneider's method and with a fully formed apices will be used in this study.
-Teeth will be flattened to obtain a standard root length of approximately 15 mm.
-The canals will be irrigated with Saline during instrumentation; 3 ml between each subsequent file size change.
-After preparation the canals will be dried with paper points. 4 -15mm of the mesiobuccal canal only will be used and the distal root will be removed by a TF-13 stone. (MANI, Japan) Samples will be divided into 2 equal groups: -Group A: Samples will be prepared by OneCurve. -Group B: Samples will be prepared by ProTaper Next.
Shaping ability of the suggested groups will be assessed by the percentage of the touched and the untouched walls.
-a custom-made brass mold will be constructed for embedding of teeth in resin blocks to standardize the photographs and facilitate the cutting and re-assembling procedures. The placement of the teeth in the uncured resin will be guided by a -parallelometer to ensure that the long axis of the tooth is parallel to the long axis of the mold until setting.
After epoxy resin polymerization, all the blocks will be marked with a 0.5 indelible ink red marker at the determined apical, middle and coronal levels (3, 6, 9 mm from the apex respectively) as reference for sectioning using ISOMET TM .
-A stereo microscope will be used to magnify and photograph the coronal aspect of each of the three sections (apical, middle and coronal) before and after instrumentation under a 16X magnification.
-After taking the post-instrumentation images and converting them to a JPEG format, a complete analysis will be made using the AutoCAD Software (Autodesk, CA, USA) to assess the surface area of the touched and the untouched walls in each group.
-Teeth will be post-operatively radiographed to assess the straightening of the canals after instrumentation which will be assessed by Schneider's method for each intervention group.

Troubleshooting
Reassembling the teeth is the process that could have some difficulties, and using a proper brass mould with tight corners can help avoiding any error while reassemblin.

Time Taken
Around a year.

Anticipated Results
Null hypothesis