الفهرس 
COVEROnly 14 pages are availabe for public view
 |  | from | 125 |  |  |
| | | from | 125 | | |
Abstract
The Aim of this study was to compare the cleaning and shaping ability of the Revo-S and Protaper rotary nickel titanium systems in terms of maintenance of canal curvature, centering ability, and the canal cleanliness.
The maintenance of canal curvature was assessed radiographically, the centering ability was evaluated using modified Bramante technique and the canal cleanliness was evaluated using the stereomicroscope.
A total of fourty human permanent mandibular molars were used in this study. Access cavities were done; the tooth length and the canal curvature of the mesial root were measured using direct digital radiography.
Samples were divided into two groups according to system used for preparation Revo-S (group I) and Protaper (group II). Each group was further divided into 2 subgroups (subgroup A and B) according to the method of evaluation. Subgroup (A) samples were evaluated for change of curvature using digital radiographic analysis and cleanliness of canals using stereomicroscopic analysis. Subgroup (B) samples were evaluated for canal centering ability using modified Bramante technique.
Evaluation of change in canal curvature:
Pre instrumentation standardized radiographs were analyzed for measuring of the canal curvature using the Image J software. Instrumentation was done according to manufacturer’s instructions for both systems. After instrumentation, standardized radiographs were also analyzed for measurement of the canal curvature after instrumentation. Data were collected and the change in curvature was calculated, then statistical analysis was performed using Instat software.
Evaluation of Canal cleanliness
Samples of the subgroup A were used for evaluation of canal cleanliness. Longitudinal sections were photographed using the stereomicroscope. Images were analyzed using Image J software for measurement of the canal surface area and the percentage of debris at the coronal, middle, and apical thirds. Data were collected and statistically analyzed
Evaluation of centering ability
A modification of Bramante’s technique was utilized in assessment of the amount of dentin removal. A specially designed assembly apparatus was used for obtaining horizontal sections of the root pre and post instrumentation at three levels; coronal, middle and apical. Sections were scanned using a high resolution scanner.
Dentin thickness was measured mesially, distally, buccally and lingually before and after instrumentation at the three levels. Linear amount of dentine removed, canal transportation and centering ratio were calculated from the previous data and statistically analyzed.