الفهرس 
Physical & mechanical properties of obturating core material and the effect of disinfectant solutionsOnly 14 pages are availabe for public view
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Abstract
A total of 130 standardized endodontic cones of ISO size 25 & taper 02 were used, they were equally divided into 2 main groups according to the type of core material (65 Gutta-percha cones and 65 Resilon cones).
The cones of each core material were divided into experimental and control groups. The experimental group was further divided into 4 groups according to the type of disinfectant solution: 2.5% Sodium Hypochlorite, 2% Chlorhexidine, 10% Povidone Iodine and 70% Ethyl alcohol in which cones were immersed in the disinfectant solution for 5 minutes.
The tensile strength evaluation was done using Universal Testing Machine (Instron 3345) under tensile loading.
Chemical composition evaluation was done using Energy Dispersive X-ray Analyzer (EDAX) attached to Scanning Electron Microscope (SEM).
Surface topography evaluation was done using Scanning Electron Microscope (SEM) and the comparison of the topographical structure of the cones was performed using the software Adobe Photoshop® CC 2017, by converting each image into grayscale then measuring the standard deviation of the intensity of the pixels obtained from SEM images at 7000× magnification, while the 3D reconstructed pictures from SEM images was performed using the software MountainsMap® Premium.
Data was tabulated for each group and statistically analyzed using one-way analysis of variance (ANOVA) & unpaired t-test using GraphPad Instat software.
Results:
Concerning the tensile strength, the results showed that there was a large statistically significant difference between the tensile strength of the two materials, With Resilon being higher than Gutta-percha in control samples and in all four types of disinfectant solutions. Disinfectant solutions didn’t cause any significant changes in both GP and Resilon, except Alcohol group
in which Resilon’s tensile strength increased significantly compared to control.
Concerning the chemical composition, the results showed that the all four disinfectant solutions didn’t cause any significant changes in the main elements present on GP and Resilon cones’ surface.
Concerning the surface topography, the results showed that there was a large statistically significant difference between the pixel intensity (surface irregularities) observed in the grey scale of SEM image of the two materials, With Resilon being rougher than Gutta-percha in control samples and in all four types of disinfectant solutions. Disinfectant solutions didn’t cause any significant changes in the surface topography in both GP and Resilon cones’ surface.
Conclusion:
Under the conditions of the present study, it can be concluded:
1. Tensile strength of Resilon is higher than that of gutta-percha.
2. Surface roughness of Resilon is greater than that of gutta-percha.
3. Disinfectant solutions (NaOCl 2.5%, CHX 2%, PVP-I 10 % and Ethanol 70%) are safe options to disinfect Gutta-percha and Resilon cones within 5 minutes of immersion time regarding their effect on tensile strength, Main Chemical components and surface topography.
Recommendations:
1. Further studies can be employed to assess the effect of disinfection of core root canal filling materials using different disinfectants on other physical properties.
2. Long term and short term effects of disinfectant solutions on core root canal filling materials can be further studied.
3. Safety parameters and Antibacterial effectiveness of disinfectant solutions can be also assessed.
4. Regarding the clinical practice, disinfectant solutions (NaOCl 2.5%, CHX 2%, PVP-I 10 % and Ethanol 70%) can be used safely to disinfect Gutta-percha and Resilon cones withen 5 minutes of immersion time without affecting their tensile strength, Main Chemical components and surface topography.