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 ofdifferent layering techniques (bulk, oblique, centripetal, splithorizontal) on the marginal microleakage of Class II adhesiverestorations.Methodology: Forty-eight standardized Class II cavities wereprepared on both mesial and distal sides of extracted non-carioushuman molar teeth. Following preparation, all specimens wererandomly divided into four groups (n=12). Group 1: bulk technique;Group 2: oblique incremental technique; Group 3: centripetalincremental technique; Group 4: split horizontal incrementaltechnique. The teeth were restored with a total-etch adhesive systemand a microhybrid composite resin. After thermocycling andimmersion in a 0.2% methylene blue solution for 24 hours, therestorations were sectioned, and dye penetration was evaluated undera stereomicroscope. The microleakage scores (0 to 4) obtained fromthe occlusal and gingival margins were analyzed with Kruskal-Wallisand Mann-Whitney U tests (p<0,05).Results: Incremental placement techniques showed lowermicroleakage compared with bulk and lower microleakage was seen atocclusal margin compared with gingival margin. However, there wereno statistically significant differences among four placementtechniques and the margins (p>0,05).Conclusions: Based on the results of the present study, none of thefour placement techniques were found to be effective in eliminatingmarginal microleakage entirely in Class II restorations. All of theplacement techniques showed similar results when the cavity marginswere located on the enamel.