Microleakage evaluation in restorations using different resin composite insertion techniques and liners in preparations with high c-factor – An in vitro study

ObjectiveTo evaluate microleakage in the enamel and cementum walls in preparations with high C factor, using three resin composite insertion techniques and two liners.Materials & methodsStandard class V cavities were prepared in buccal and lingual aspects of 36 caries free, extracted premolars. The teeth were randomly assigned to three groups of 12 each corresponding to three different insertion techniques (1) Oblique insertion (2) Horizontal insertion and (3) Bulk insertion and then subdivided into three groups of four each depending on the type of liner used (1) no liner (2) RMGIC liner (GC fuji II LC) and (3) Flowable composite liner (Tetric flow, Ivoclar vivadent). The preparations were etched and restored with an Adhesive (adper single bond 2 3M ESPE), Liner (except for the no liner group) and Microhybrid resin composite (Z100, 3M ESPE). Specimens were isolated with nail varnish except for 2 mm wide rim around the restoration, thermocycled (1000 thermal cycles, 5/55 °C, 30 s dwell time) and then immersed in an aqueous solution of 50 wt% silver nitrate for 24 h followed by 8 h in a photo developing solution and evaluated for microleakage using a stereomicroscope on an ordinal scale of 0–4. The microleakage scores were analyzed by using the chi square test.ResultsOblique incremental technique coupled with the use of flowable composite liner gave better results when compared to other groups at the cementum margins.ConclusionNone of the insertion techniques nor the use of liners were able to eliminate microleakage completely; however the use of the oblique insertion technique coupled with the use of flowable composite liner gave better results.