ABSTRACT
Statement of Problem: shear bond strength [SBS] of home and office bleached enamel will be compromised by immediate application of composite restoration. Antioxidant agent may overcome this problem
Objectives: this in vitro study assessed the effect of green tea extract on shear bond strength of resin composite to in-office and home-bleached enamel
Materials and Methods: in this experimental study, 40 extracted intact human incisors were embedded in cylindrical acrylic resin blocks [2.5 ×1.5 cm], with the coronal portion above the cemento enamel junction out of the block. Then, after bleaching labial enamel surfaces of 20 teeth with 15% carbamide peroxide 6 hours a day for 5 days, they were randomly divided into two groups: A1 and A2 [n = 10], depending upon whether or not they are treated with antioxidant. Labial enamel surfaces of the remaining 20 teeth were bleached with 38% hydrogen peroxide before being randomly divided into groups B1 and B2 [n = 10], again depending on whether or not the antioxidant was used in their treatment . The experimental groups [A2,B2] were treated with 5% solution of green tea extract before resin composite restoration was done by a cylindrical Teflon mould [5×2 mm]. Shear bond strength of the specimens was tested under a universal testing machine [Zwick/Roell Z020]. The SBS data were analyzed by using One-way ANOVA and Tukey HSD tests [p < 0.05]
Results: there were no statistically significant differences between shear bond strength of the control group [A1] and treated group [A2], but there were statistically significant differences between the groups B1 and B2 [p < 0.05]
Conclusions: application of antioxidant did not increase the shear bond strength of home-bleached enamel to resin composite but its application increased the shear bond strength of in-office bleached enamel to resin composite
ABSTRACT
Statement of Problem: hemostatic agents may affect the micro-leakage of different adhesive systems. Also, chlorhexidine has shown positive effects on micro-leakage. However, their interaction effect has not been reported yet
Objectives: to evaluate the effect of contamination with a hemostatic agent on micro-leakage of total- and self-etching adhesive systems and the effect of chlorhexidine application after the removal of the hemostatic agent
Materials and Methods: standardized Class V cavity was prepared on each of the sixty caries free premolars at the cemento-enamel junction, with the occlusal margin located in enamel and the gingival margin in dentin. Then, the specimens were randomly divided into 6 groups [n = 10] according to hemostatic agent [H] contamination, chlorhexidine [CHX] application, and the type of adhesive systems [Adper Single Bond and Clearfil SE Bond] used. After filling the cavities with resin composite, the root apices were sealed with utility wax. Furthermore, all the surfaces, except for the restorations and 1mm from the margins, were covered with two layers of nail varnish. The teeth were immersed in a 0.5% basic fuschin dye for 24 hours, rinsed, blot-dried and sectioned longitudinally through the center of the restorations bucco- lingualy. The sections were examined using a stereomicroscope and the extension of dye penetration was analyzed according to a non-parametric scale from 0 to 3. Statistical analysis was performed using Kruskal-Wallis test and Mann-Whitney U-test
Results: while ASB group showed no micro-leakage in enamel, none of the groups showed complete elimination of micro-leakage from the dentin. Regarding micro-leakage at enamel, and dentin margins, there was no significant difference between groups 1 and 2, 1 and 3, and 2 and 3 [p > 0.05]. A significantly lower micro-leakage at the enamel and dentin margins was observed in group 3, compared to group 6. No significant difference was observed between groups 4 and 5 in enamel [p = 0.35] and dentin [p = 0.34]. Group 6 showed significantly higher micro-leakage, compared to group 4 and 5 [p < 0.05]
Conclusions: hemostatic agent contamination had no significant effect on micro-leakage of total- and self-etching adhesive systems. Application of chlorhexidine after the removal of hemostatic agent increased micro-leakage in self-etching adhesives but did not affect when total-etching was used
ABSTRACT
In order to define the protein expressional changes related to the process of meglumine antimoniate resistance in anthroponotic cutaneous leishmaniasis [CL], we performed a comparative proteomics analysis on sensitive and resistant strains of Leishmania tropica isolated from Iranian CL patients. Cell proteins were analysed with 2-dimensional electrophoresis and differentially expressed proteins were identified by matrix-assisted laser desorption/ ionization time-of-flight mass spectrometry. Image analysis of the matched maps identified 7 proteins that were either over- or down-expressed: activated protein kinase c receptor [LACK], alpha tubulin [X2], prostaglandin f2-alpha synthase, protein disulfide isomerase, vesicular transport protein and a hypothetical protein. The study shows the usefulness of proteomics in identifying proteins that may express differences between sensitive and resistant L. tropica isolates