A 2-year Clinical Impact of Bulk-fill Low-viscosity Resin Composite Liners in Class II Restorations.

This randomized clinical trial evaluated the clinical performance of class II resin composite restorations using bulk-fill high-viscosity ormocer versus methacrylate-based with or without a thin layer of bulk-fill low-viscosity (flowable) resin composite liners (BLRC) over 2 years. The null hypotheses in the study were as follows: (1) Different types of matrix structures (ormocer vs. methacrylate) have no effect on the marginal integrity of restorations; (2) A layer of bulk-fill resin compo-site liner of the same category would not affect the marginal or internal adaptation of restorations.