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Aim:The aim of this ex vivo study was to compare the antibacterial activity of total-etch and self-etch adhesive systems against Streptococcus mutans, Lactobacillus acidophilus, and Actinomyces viscosus through disk diffusion method.Materials and Methods:The antibacterial effects of Single Bond (SB) and Adper Prompt (AP) and aqueous solution of chlorhexidine 0.2% (positive control) were tested against standard strain of S. mutans, L. acidophilus, and A. viscosus using the disk diffusion method. The diameters of inhibition zones were measured in millimeters. Data was analyzed using Kruskal-Wallis test. Mann-Whitney U test was used for pairwise comparison.Result:Of all the materials tested, AP showed the maximum inhibitory action against S. mutans and L. acidophilus. Aqueous solution of chlorhexidine 0.2% showed the maximum inhibitory action against A. viscosus. Very minimal antibacterial effect was noted for SB.Conclusion:The antibacterial effects observed for the tested different dentin bonding systems may be related to the acidic nature of the materials.

Aims: To determine the effect of novel dry bonding approaches on the shear bond strength of universal adhesive. Settings and Design: Methods and Material: The occlusal surface of forty extracted human molars were sectioned to expose the superficial dentin. The samples were randomly divided into four groups with 10 samples in each. The bonding to composite resin was done by a universal adhesive in the first group by self etch approach, second group by etch and rinse approach, the third and fourth groups were bonded by etch and rinse approach but additionally they were treated with Grape seed extract (GSE) and Dimethyl Sulfoxide (DMSO) prior to the application of the bonding agent according to the novel dry bonding approaches. Then, resin composite was inserted into a plastic tube placed on the specimen and light polymerized as per manufacturer's instructions. 5 samples in each group were stored in distilled water at 37°C for 24 hrs, the rest of the 5 samples in each group were thermocycled to mimic 1 year of aging. Then, shear bond strength analysis was done at a crosshead speed of 1.0 mm/min in a universal testing machine. Finally, the mode of failure was analysed under a stereomicroscope. Statistical analysis used: The statistical analysis for comparison of the mean bond strengths among the various groups was accomplished by Post-hoc Mann whiteney and Kruskal Wallis test. Results: Thermocycling significantly reduced the bond strength in etch and rinse group. The highest bond strength at 24 hrs and at one year was observed in DMSO treated group. Adhesive failure was seen more frequently in all the groups. Conclusions: DMSO treated group showed significantly higher bond strength and bond durability.

Aim: The aim of the study is comparative evaluation of efficacy of neo endo retreatment files after autoclave and cold sterilization. Materials And Methods: 45 human mandibular premolars with a single straight root canal were selected and decoronated leave 16mm of root.The working length was determined by subtracting 1mm from above measurment. Canal preparation was done with Neo endo flex rotary files (25/6) and were obturated with GP size 25/6% .After 2 weeks of storage in normal saline they were randomly divided into three groups .In Group A (5 sub-groups :A1, A2, A3, A4 and A5 of 3 sets of specimens) Neo endo retreatment files were subjected to sterilization by autoclaving.In group B files were sterilized by cold sterilization with 2.4% Glutaraldehyde solution for 12 hours.In Group C files were cleaned using soap and water . Statistical analysis was done with One-way ANOVA Test followed by Tukeys post hoc test to compare the mean remaining GP & time taken between different groups and usage times. Result: All samples showed GP remnants. Irrespective of the sterilization methods used, the amount of remaining GP increased sequentially from first to fifth use along with usage time. The remaining GP was lesser in the group A where sterilization was done by autoclave, and remaining GP was highest in Group C where no sterilization was done. The remaining GP of Group B ( Cold sterilization) was higher than Group A and lower than Group C. Conclusion :From the findings of present study it can be concluded that Autoclave sterilization causes least changes to the physical properties of the files when compared to Gluteraldehyde sterilization which adversely effects the cutting efficiency of the files. Unsterilized files exhibits least cutting efficiency resulting in reduced gutta percha removal from the canals. Also the number of use was a determining factor for cutting efficiency. Reduction in the cutting effectiveness of instruments may increase operating time and it could take longer to remove the material from root canal.

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