title: The effect of curing conditions on the physical properties of tricalcium silicate cement for use as a dental biomaterial.
abstract: OBJECTIVE
  To investigate the physical properties of tricalcium silicate (TCS) with and without the addition of a radiopacifier and compare them with that of Portland cement (PC) and radiopaque PC in an mineral trioxide aggregate-like system.
  
  
  METHODS
  Tricalcium silicate, PC and radiopacified variants containing 20% bismuth oxide were tested for radiopacity, compressive strength, setting time and dimensional stability. All the testing was performed at 37 °C and under different environmental conditions namely at 100% humidity or immersed in either water or Hank's balanced salt solution (HBSS). Testing was performed after both 1 and 28 days.
  
  
  RESULTS
  The cements exhibited radiopacity values equivalent to <3 mm. Addition of 20% bismuth oxide resulted in adequate radiopacity. The strength of TCS was independent of the curing conditions. The cements without radiopacifier had improved strength characteristics when immersed in HBSS, whilst the radiopacified cements exhibited higher strengths when soaked in water. Tricalcium silicate demonstrated the shortest setting time. Addition of bismuth oxide increased the setting time of the cements while HBSS inhibited the setting of bismuth oxide-replaced cements. The PC-based materials exhibited a net contraction higher than that recorded for TCS-based cements in all curing conditions. The dimensional change exhibited by the specimens was generally greater in the first few hours of setting, but then stabilized with time.
  
  
  CONCLUSIONS
  Tricalcium silicate cement required the addition of a radiopacifying agent to make it suitable for use as a dental material. Tricalcium silicate exhibited adequate physical properties and thus was shown to be a suitable replacement for the PC component in MTA. Bismuth oxide drastically increased the setting time of the test cements in phosphate-containing solutions. Alternative radiopacifiers that do not retard the setting time need to be investigated.
authors: Department of Metallurgy and Materials Engineering, Faculty of Engineering, University of Malta, Msida, Malta.
authors: L M
authors: LM
authors: Formosa
authors: B
authors: B
authors: Mallia
authors: J
authors: J
authors: Camilleri
mesh_terms: D017607:Aluminum Compounds / Q000737:chemistry; D001672:Biocompatible Materials / Q000737:chemistry*; D001729:Bismuth / Q000737:chemistry; D017610:Calcium Compounds / Q000737:chemistry*; D055598:Chemical Phenomena; D019245:Compressive Strength; D003287:Contrast Media / Q000737:chemistry; D003738:Dental Cements / Q000737:chemistry*; D004338:Drug Combinations; D006801:Humans; D006813:Humidity; D007552:Isotonic Solutions / Q000737:chemistry; D008422:Materials Testing; D010087:Oxides / Q000737:chemistry; D017640:Silicates / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D017607:Aluminum Compounds; D001672:Biocompatible Materials; D017610:Calcium Compounds; D003287:Contrast Media; D003738:Dental Cements; D004338:Drug Combinations; C072670:Hanks Balanced Salt Solution; D007552:Isotonic Solutions; D010087:Oxides; D017640:Silicates; C086631:mineral trioxide aggregate; D014867:Water; C506393:tricalcium silicate; C033301:bismuth oxide; D001729:Bismuth