Porosities in composite resin can be incorporated at many stages of packaging and placement. Porosities can be minimized through vacuum loading of syringes and use of light-curing materials that require minimal handling. Even so, the method of placement of the material can lead to inclusion of submicron bubbles in the resin or formation of structures and pockets that can trap air at the surface. The consequences of material viscosity, method of placement, and cavity design are examined in relation to porosity incorporation.