title: High-resolution tomography study of the porosity of three restorative resin composites.
abstract: OBJECTIVE
  The aim of this study was to analyze the porosity of three photopolymerizable resin composites: one high-viscous resin composite (Filtek™ P60®, 3 M™ ESPE™), one moderate-viscosity resin composite (Grandio®, VOCO™), and one low-viscous resin composite (Filtek™ Supreme XTE®, 3 M™ ESPE™).
  
  
  METHODS
  A total of 36 cylindrical samples with a height of 2 mm and a diameter of 2 mm were prepared using PTFE molds. Eighteen cylinders were prepared by two incremental applications of 1 mm into the molds, then polymerized (group 1). For the other 18 samples (group 2), the first increment was polymerized before the second addition was made. The average porosity percentage and the average porosity volume were evaluated by high-resolution tomography (Nanotom M® - Phoenix X-Ray(TM), Wunstorf, Germany). The impact of incremental applications in terms of porosity was also evaluated.
  
  
  RESULTS
  Irrespective of the protocol used, the low viscous material presented an average porosity percentage and an average porosity volume significantly greater than those of the other materials. Incremental application (group 2 samples) led to an increase in the average porosity percentage and volume irrespective of the material compared to the group 1 samples.
  
  
  CONCLUSIONS
  High-resolution tomography appeared to be a particularly suitable tool for studying the porosity of resin composites. The viscosity and the handling of these materials seemed to be influential factors on their porosity.
  
  
  CONCLUSIONS
  The presence of porosities in dental resin composites remains an objective reality, especially with low-viscous resin composites. Since the intrinsic porosity of the materials can be neither controlled nor modified by the operator, rigorous and iterative clinical protocols still remain the best way to limit inclusion of porosities in the resin composites.
authors.affiliation: Laboratoire de Science et Ingénierie des Matériaux et Métallurgie, École des Mines, Parc de Saurupt, 54000, Nancy, France.
authors.forename: R
authors.initials: R
authors.lastname: Balthazard
authors.forename: S
authors.initials: S
authors.lastname: Jager
authors.forename: A
authors.initials: A
authors.lastname: Dahoun
authors.forename: D
authors.initials: D
authors.lastname: Gerdolle
authors.forename: M
authors.initials: M
authors.lastname: Engels-Deutsch
authors.forename: E
authors.initials: E
authors.lastname: Mortier
mesh_terms: D003188:Composite Resins; D003793:Dental Restoration, Permanent; D016062:Porosity; D014054:Tomography / Q000379:methods*
chemical_list: D003188:Composite Resins