title: A systematic approach to standardize artificial aging of resin composite cements.
abstract: OBJECTIVE
  The aim of the investigation was to contribute to the ongoing discussion at the international standardization committee on how to artificially age dental resin composite cements.
  
  
  METHODS
  Indirect tensile strength (n=30) of a dual-cured resin composite cement (Panavia F2.0) was measured to evaluate the effect of water storage at 37°C or thermal cycling (5°C/55°C/1min) for up to 64 days. The influence of water temperature (5-65°C) after 16 days and the effect of 1 day water storage at 37°C prior to aging were assessed. Storage in air at 37°C served as control.
  
  
  RESULTS
  Thermal cycling affected the indirect tensile strength most, followed by water storage at 55°C, whereas water storage at 37°C had only little influence. Major deterioration occurred before day 4 (≈6000 cycles). A 1-day pre-treatment by water storage at 37°C prior to thermal cycling attenuated the effect of aging.
  
  
  CONCLUSIONS
  For the material investigated, thermal cycling for 4 days is the most efficient aging procedure. A 1-day water storage at 37°C prior to thermal cycling is recommended to allow complete polymerization. A 4-day water storage at 55°C may be considered as a viable alternative to thermal cycling.
authors.affiliation: Department of Dental Materials and Engineering, University Hospital of Dental Medicine, University of Basel, Basel, Switzerland.
authors.forename: Lukas
authors.initials: L
authors.lastname: Blumer
authors.affiliation: Department of Dental Materials and Engineering, University Hospital of Dental Medicine, University of Basel, Basel, Switzerland.
authors.forename: Fredy
authors.initials: F
authors.lastname: Schmidli
authors.affiliation: Department of Periodontology, Endodontology and Cariology, University Hospital of Dental Medicine, University of Basel, Basel, Switzerland.
authors.forename: Roland
authors.initials: R
authors.lastname: Weiger
authors.affiliation: Department of Dental Materials and Engineering, University Hospital of Dental Medicine, University of Basel, Basel, Switzerland; VITA Zahnfabrik, Bad Säckingen, Germany. Electronic address: jens.fischer@unibas.ch.
authors.forename: Jens
authors.initials: J
authors.lastname: Fischer
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000268:Adhesiveness; D003188:Composite Resins / Q000737:chemistry*; D003799:Dental Stress Analysis; D006244:Hardness; D008422:Materials Testing; D011140:Polyurethanes / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature; D013718:Tensile Strength; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; C029012:Composite Dental Resin; D003188:Composite Resins; D011140:Polyurethanes; D014867:Water
keywords: Aging; Compressive strength; Indirect tensile strength; International standardization; Resin composite cement; Thermal cycling