Porosity of restorative resins.

– Polyethylene tubes were filled with different types of composite resins using either the bulk-packing technique or the syringe injection technique. The porosity of the specimens was studied. Specimens made by light-activated systems were less porous compared to specimens made by two-paste systems. Use of the injection technique was followed by a reduction in porosity in both groups compared to use of the bulk-packing technique.