title: Physicomechanical characterization of polyetheretherketone and current esthetic dental CAD/CAM polymers after aging in different storage media.
abstract: BACKGROUND
  Polyetheretherketone (PEEK) can be used to support fixed dental prostheses. However, information about physicomechanical characterization is still scarce.
  
  
  OBJECTIVE
  The purpose of this in vitro study was to assess effects of different aging regimens/durations on roughness, solubility, water absorption, Martens hardness (HM), and indentation modulus/EIT on different computer-aided design and computer-aided manufacturing (CAD/CAM) polymers.
  
  
  METHODS
  Forty standardized specimens of the following materials were fabricated: PEEK: Dentokeep (DK); hybrid material: VITA Enamic (EN); composite resins: LAVA Ultimate (LU) and an experimental CAD/CAM nanohybrid-composite resin (EX); poly(methyl methacrylate) (PMMA)-based: VITA CAD-Temp (CT); Telio CAD (TC), artBloc Temp (AT), and ZENOTEC ProFix (ZP). A nanofilled-polymer for interim restorations, Protemp 4 (CG), served as the control group. Specimens were stored in sodium chloride, artificial saliva, physiological saliva, and distilled water at 37°C for 1, 7, 14, 28, 90, and 180 days. Roughness, water absorption, HM, and EIT were investigated after each storage period; solubility was determined after 180 days only. Data were analyzed using weighted 3/2/1-way ANOVA and the post hoc Scheffé tests (α=.05).
  
  
  RESULTS
  Storage media had no effect on surface roughness and water absorption. Physiological saliva revealed the highest significant impact on solubility followed by artificial saliva, sodium chloride, and distilled water. Water absorption increased significantly with storage duration. PEEK showed the lowest solubility and water absorption values. The highest solubility was observed for the conventional polymer CG, and the highest water absorption was found for the composite LU. PMMA-based TC, ZP, CG, and AT showed the lowest HM and indentation modulus, followed by CT, and PEEK. The highest values were observed for the hybrid material EN, followed by LU and EX.
  
  
  CONCLUSIONS
  The hardness parameters of PEEK were comparable with those of PMMA-based materials.
authors.affiliation: Assistant Professor, Department of Prosthodontics, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Liebermann
authors.affiliation: Head, Outpatient Department, Department of Prosthodontics, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Timea
authors.initials: T
authors.lastname: Wimmer
authors.affiliation: Head, Periodontology and Peri-Implant Diseases, Clinic of Preventive Dentistry, Periodontology and Cariology, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
authors.forename: Patrick R
authors.initials: PR
authors.lastname: Schmidlin
authors.affiliation: Dentist, Department of Prosthodontics, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Harry
authors.initials: H
authors.lastname: Scherer
authors.affiliation: Dentist, Department of Prosthodontics, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Löffler
authors.affiliation: Senior Statistician, Department of Biostatistics, Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland.
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Roos
authors.affiliation: Scientific Head, Dental Materials Unit, Department of Prosthodontics, Ludwig-Maximilians-University, Munich, Germany. Electronic address: bogna.stawarczyk@med.uni-muenchen.de.
authors.forename: Bogna
authors.initials: B
authors.lastname: Stawarczyk
mesh_terms: D001577:Benzophenones; D001672:Biocompatible Materials; D003188:Composite Resins; D017076:Computer-Aided Design; D004955:Esthetics, Dental; D006801:Humans; D066298:In Vitro Techniques; D007659:Ketones / Q000737:chemistry*; D008422:Materials Testing; D011092:Polyethylene Glycols / Q000737:chemistry*; D011108:Polymers; D019904:Polymethyl Methacrylate; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors
chemical_list: D001577:Benzophenones; D001672:Biocompatible Materials; D003188:Composite Resins; D007659:Ketones; D011108:Polymers; C063834:polyetheretherketone; D011092:Polyethylene Glycols; D019904:Polymethyl Methacrylate