The Porosities or Voids Included in Composite Resin Restorations

Purpose: The aim of this in vitro study was to investigate effects of consistency of resin composite and insertion techniques on the formation of porosity or inclusion of air bubbles in resin composite restorations. Materials and Methods: Three resin composites (Tetric Ceram HB, Tetric EvoCeram and Prodigy) were selected to represent high, intermediate and low viscosity, respectively. Simulated Class I cavities prepared in acrylic resin blocks were restored with one of the composites using both hand-instrument insertion and injection insertion techniques. The restorations were sectioned longitudinally and microscopically examined for the presence of porosity. Results: The materials of low (Prodigy) and high Tetric Ceram HB) viscosity exhibited a significantly less porosity than the material of a mediate viscosity. The porosities of Prodigy and Tetric Ceram HB restorations were comparable regardless of the insertion technique. Tetric EvoCeram restorations inserted by the hand technique contained more porous inclusions than those inserted using the injection technique. Conclusion: Porosities inside resin composite restorations apparently arose during the filling process, and the consistency of resin composite influenced the porosity formation of the composite restoration. Injection insertion was not found necessary to reduce porosities.