Effect of Total Etch and Universal Adhesives on Microleakage between Composite and Glass Ionomer in Class II Sandwich Restorations

Background and purpose: Microleakage is the most common cause of secondary caries and failure of restorations. The aim of this study was to evaluate the Microleakage between resin modified glass-ionomer (RMGI) and resin composite in sandwich restorations using different bonding agents. Forty four premolars were used in this experimental study. Class II cavities were prepared and the gingival margin placed 1 mm below cementoenamel junction. RMGI (Fuji II LC) was inserted on the gingival floor in 1 mm thickness and the teeth were divided into two groups. Group I: cavities were etched, rinsed and treated with a total etch adhesive (Adper single bond 2). Group II: An universal adhesive (Single bond universal) was applied in self etch mode. All cavities were then restored incrementally using resin composite (Filtek Z 250). To evaluate the microleakage, the samples were subjected to thermocycling (3000 cycles), immersed in methylene blue for 72 hours, and sectioned mesiodistally. The samples were subsequently observed under stereomicroscope. Mann-Whitney test was used to analyze the data (P<0.05). The microleakage was significantly higher in Adper single bond 2 group (520.5±401.5µm) compared with that in single bond universal group (193±269.5µm). This study showed that application of universal adhesive between RMGI and composite in self etch mode leads to lower microleakage compared with total etch adhesive in open sandwich restorations.