The effect of two different polishing techniques on microleakage of new composites in Class V restorations.

AIM: The purpose of this study was to investigate the effect of polishing systems on the microleakage of a nanofill, a nanohybrid, and a microhybrid composite in Class V cavities.

METHODS AND MATERIALS: Preparations were made at the cemento-enamel junction (CEJ) of 36 extracted human premolars. The teeth were randomly divided into three groups and restored with new resin composites according to the manufacturers' instructions as follows: Group 1, Filtek Supreme & Single Bond; Group 2, Grandio & Solobond; and Group 3, Artemis & Excite. The restorations were finished with diamond finishing burs. The restored/finished teeth were randomly divided into two groups and polished using the following systems: Super-Snap (Al2O2 coated, abrasive disc system, fine grit, and extra fine grit) and Astropol/Astrobrush (silicon-based abrasive polisher point and polisher brush). All specimens were thermocycled 1000 times with a 10 second dwell time. They were immersed in 0.5% aqueous basic fuchsin dye for 24 hours and then sectioned buccal-lingual-longitudinally through the center of both restorations of each tooth and evaluated under a stereomicroscope at 30X magnification. The degree of dye penetration was quantified.

RESULT: No significant difference in leakage scores was observed in enamel margins (p=0.456, Kruskall Wallis test), but dentin margins were significantly affected by the different polishing systems (p=0.037, Kruskall Wallis test). The lower leakage scores were recorded for Astropol/Astrobrush polishing systems. The nanofill composite showed the least leakage among the test groups in this study. The most leakage was observed in nanohybrid composite resin (p<0.05, Mann Whitney U test).

CONCLUSIONS: Under the conditions of this in vitro study: the microleakage resistance of composites at enamel margins is not significantly affected by the different polishing systems; the lowest leakage scores were recorded for Astropol/Astrobrush polishing techniques in different types of composites; and the ranking of the composite materials from most to least leakage at the dentin margins according to polishing techniques was Grandio >Artemis > Filtek Supreme.