RESUMO
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
RESUMO
In the recent years, the demand for esthetic restoration led to development of tooth colored post. The establishment of reliable retention between post and root canal is an important factor. Current prefabricated tooth-colored posts are fiber and zirconia posts. Loss of fitness in these posts reduces the post retention; therefore, there is a need for fabricating a tooth colored post that may be fitted in the root canal. The aim of this study was to compare the bond strength of fiber posts and custom made zirconia posts with two cement types [resin cement and zinc phosphate] to root dentin. Thirty-two single root extracted teeth were prepared and endodontically treated. They were divided into two groups [fiber post, zirconia post]; in each group two cement subgroups [zincphosphate and panavia F2] were used for cementation. Bond strength was measured with the push-out method. Failure modes were observed under a stereomicroscope [20x]. Data were analyzed with the two way ANOVA test. In both post groups, bond strengths of panavia F2 were higher than zinc phosphate. The least bond strength was for fiber post/zinc phosphate group [4.60MPa] and the highest bond strength was for zirconia/Panavia F2[14.92 MPa]. Most of the failures were at the post-cement interface. Higher bond strength may be achieved with custom made zirconia post and resin cement than fiber posts. So, fitness is a critical factor in post retention and we should not rely only on the bonding ability of resin cement for post retention