Which generation of flowable composite can be used as restorative material?

Because flowable composites were developed with specific handling characteristics in mind,their  range of advertised clinical uses is quite varied. Within the range of materials classified as flowable  composites, those with lower filler content (often referred as generation 1 flowable composites) are  intended for uses such as pit-and-fissure sealants or small anterior restorations.  Those with higher filler content (also referred as generation 2 flowable composites) have been suggested for use in Classes I, II, III, IV, and V restorations, although they are better suited only for very conservative  restorative procedures.  In general, the mechanical properties of flowable composites are inferior to  those of standard hybrid composites.