ABSTRACT
some recent research have reported increased stability in mechanisms of adhesion to dentin in remove of collagen fiber of the dentin surface.The aim of this study was to evaluate the effect of sodium hypochlorite in microleakage of three step total etch dental adhesives with different solvents. this experimental study on 80 intact bovine incisor teeth, were prepared class V cavities on buccal surface of teeth, box shap and all walls on enamel. Then the specimens were randomly divided into eight groups [n=10]. NaOCl+etching+ SBMP [waterbase], NaOCl+etching+ All Bond[2] [Acetonebase], etching+ NaOCl+ SBMP, etching+ NaOCl+ All Bond[2], NaOCl+ SBMP, NaOCl+ All Bond[2], etching+ SBMP, etching+ All Bond[2]. Then the cavities were restored using Z[250] [3M] composite and Coltolux 75 light curing unit [350 mw/cm2]. The specimens were thermo cycled for 1000 times on water baths of 5 and 55[Oc]. After thermocycling, the specimens were immersed in a 2% aqueous solutions of basic fuchsin for 24 hours, then longitudinal section of each restoration was obtained and examined with a stereomicroscope for evaluation of micro leakage. The data were analyzed using kruskal-walls test and the mean of micro leakage of samples were compared by two- way ANOVA test. The findings showed that the higher rate of micro leakage was detected in hypo+Acid and lower rate of micro leakage was detected in Acid+hypo in different treatment method. The finding was different in hypo+Acid procedure, the higher rate of micro leakage was in SBMP. In hypo groups, the microleakage with ALL Bond 2 was higher than SBMP. In control groups, the microleakage with SBMP was higher than ALL Bond 2. Application of Naoci before dentin etching for removal organic materials increase the rate of microleakage of All Bondz, SBMP to that of control group
ABSTRACT
Lack of appropriate seal is one of the major problems in composite restorations. Properties of the bonding system can play a crucial role in sealing ability of these restorations. The aim of this study was to evaluate the microleakage of composite restorations with varying irradiation time for curing dentin bonding agents with two different curing devices in class V cavities. In this experimental study, 60 intact extracted human molars and premolars were subjected to standard class V cavity preparations. Cavities were divided to six groups. Following etching, Excite bonding agent was applied and light cured using QTH and LED systems for 20, 30 and 40 seconds and cavities were filled with composite. The filled cavities were subjected to 3000 thermal cycles with 5-55 degree temperatures. Teeth were immersed into 0.5% basic fushin dye and sectioned occlusogingivally from the restoration middle area and the microleakage was determined using stereomicroscope by a 5-scaled rankings. Data were analyzed by Mann-Whitney and Kruskal-Wallis tests with p<.0.05 as the level of significance. No leakage was found in enamel margins. The type of light curing device did not have any significant effect on dentin margins microleakage [p>0.05]. Furthermore, no significant reduction in microleakage scores were observed in the restorations irradiated with different curing times [p>0.05]. QTH and LED curing units in 20, 30, and 40 s curing time did not have any significant effect on microleakage of class V composite restoration margins