Opus Bulk Fill Flow is a low viscosity (fluid) photocurable composite resin indicated for the base and lining of restorations in posterior teeth. Its low contraction stress associated with its high depth of cure - made possible by the high translucency of the composite - allows Opus Bulk Fill Flow to make increments of up to 4mm, minimizing the time for making large restorations. With approximately 68% load by mass, the composite has sufficient mechanical strength to be used under direct restorations. The most superficial layer of the restoration (with a thickness of at least 2mm) must be made with conventional methacrylate-based composite resins, eg: Opallis (FGM), Llis (FGM), Opus Bulk Fill Condensable (FGM). This layer gives the restoration greater mechanical resistance, wear resistance, shape and aesthetics.