Evaluation of microleakage in posterior nanocomposite restorations with adhesive liners

AIMS AND OBJECTIVES To compare the microleakage in class II nanocomposite restorations without liner, with resin-modified glass ionomer liner and flowable composite liner. MATERIALS AND METHODS Thirty-six sound premolars extracted for orthodontic reasons were selected and randomly assigned into three groups of 12 teeth each (Group I, II and III). Class II cavities of specified dimensions were prepared with margins located in the enamel. Cavities in group I were lined with resin modified glass ionomer (GC Fuji II LC-Improved), group II were lined with flowable composite (Filtex Z350 Flowable Restorative) and no liner was placed for cavities in group III. All the teeth were restored with nanocomposite (Z 350 Universal Restorative). The teeth were immersed in 0.5% methylene blue dye, sectioned mesiodistally and observed under stereomicroscope. RESULTS Group III showed maximum leakage compared to group I and II which was statistically significant. Microleakage was lesser in group lined with resin-modified glass ionomer as compared to flowable composite group but not statistically significant. CONCLUSIONS Placement of liner beneath nanocomposite restoration results in significant reduction in microleakage. Both resin-modified and flowable composite liners under nanocomposite restorations result in comparable reduction of microleakage.