title: Clinical relevance of antimicrobial testing results for dental restorative materials.
abstract: BACKGROUND
  The antimicrobial activity of restorative materials is clinically relevant because all dental materials are subject to an environment containing bacteria. This study aimed to investigate the use of 2 methodologies referred to in the literature to assess antimicrobial properties of restorative materials and investigate whether material properties alter results of these traditional methodologies.
  
  
  METHODS
  A number of dental restorative materials - namely, Chemfil Superior®, Spectrum®, Heliobond®, Ionoseal®, Dyract Extra®, Smart Dentin Replacement (SDR®) and Biodentine® - were characterized by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD) analysis, Fourier transform infrared (FT-IR) spectroscopy and pH analysis. Antimicrobial activity was assessed using agar diffusion and biofilm accumulation tests. Key factors affecting results were assessed using analysis of covariance.
  
  
  RESULTS
  Biodentine after immediate mixing and Ionoseal aged for 6 weeks resulted in an inhibition zone, while significantly higher McFarland readings were observed in the presence of barium when using materials Ionoseal, Dyract and SDR at 24-hour aging. Through analysis of covariance it was shown that material properties affected methodology results.
  
  
  CONCLUSIONS
  Properties of materials affect results of antimicrobial testing, but this may not directly reflect the antimicrobial potential of the material in question. Careful choice of methodology and interpretation of results is important.
authors.affiliation: Department of Restorative Dentistry, Faculty of Dental Surgery, University of Malta, Msida - Malta.
authors.forename: Cher
authors.initials: C
authors.lastname: Farrugia
authors.affiliation: Department of Pathology, Mater Dei Hospital, Msida - Malta.
authors.forename: Julie
authors.initials: J
authors.lastname: Haider
authors.affiliation: Department of Statistics and Operations Research, Faculty of Science, University of Malta, Msida - Malta.
authors.forename: Liberato
authors.initials: L
authors.lastname: Camilleri
authors.affiliation: Department of Restorative Dentistry, Faculty of Dental Surgery, University of Malta, Msida - Malta.
authors.forename: Josette
authors.initials: J
authors.lastname: Camilleri
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D003764:Dental Materials; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: D000890:Anti-Infective Agents; D003764:Dental Materials