Evaluation of marginal microleakage in composite restorations with different placement techniques

Abstract

Aim: The purpose of this in vitro study was to evaluate the effect of different layering techniques (bulk, oblique, centripetal, split horizontal) on the marginal microleakage of Class II adhesive restorations.
 Methodology: Forty-eight standardised Class II cavities were prepared on both mesial and distal sides of extracted non-carious human molar teeth. Following preparation, all specimens were randomly divided into four groups (n=12). Group 1: bulk technique; Group 2: oblique incremental technique; Group 3: centripetal incremental technique; Group 4: split horizontal incremental technique. The teeth were restored with a total-etch adhesive system and a microhybrid composite resin. After thermocycling and immersion in a 0.2% methylene blue solution for 24 hours, the restorations were sectioned, and dye penetration was evaluated under a stereomicroscope. The microleakage scores (0 to 4) obtained from the occlusal and gingival margins were analysed with Kruskal-Wallis and Mann-Whitney U tests (p<0,05).
 Results: Incremental placement techniques showed lower microleakage compared with bulk and lower microleakage was seen at occlusal margin compared with gingival margin. However, there were no statistically significant differences among four placement techniques and the margins (p>0,05).
 Conclusion: Based on the results of the present study, none of the four placement techniques were found to be effective in eliminating marginal microleakage entirely in Class II restorations. All of the placement techniques showed similar results when the cavity margins were located on the enamel.