title: Mineral trioxide aggregate with anti-washout gel - properties and microstructure.
abstract: OBJECTIVE
  One of the problems encountered clinically when using mineral trioxide aggregate (MTA) as a root-end filling material is washout immediately after placement. A novel MTA is supplied with an anti-washout gel that replaces the mixing water. The aim of this research was to characterize and assess the properties of a novel MTA mixed with an anti-washout liquid.
  
  
  METHODS
  MTA Plus mixed with either water (MTA-W) or an anti-washout gel (MTA-AW) was investigated. Un-hydrated and set materials were characterized by scanning electron microscopy (SEM), energy X-ray dispersive analysis (EDX), X-ray diffraction analysis (XRD) and Fourier transform infrared spectroscopy (FT-IR) after being stored dry or immersed in Hank's balanced salt solution (HBSS). The chemical and physical properties of the set materials were then investigated.
  
  
  RESULTS
  The MTA Plus was composed of tricalcium silicate, dicalcium silicate and bismuth oxide. The anti-washout gel used was water-based and FT-IR plots showed the presence of an organic additive. Both materials immersed in HBSS displayed the presence of reaction by-product with MTA-W exhibiting a high-intensity calcium hydroxide peak on X-ray diffraction. The X-ray diffractograms of all materials following hydration demonstrated the reduction in peak intensity of the tri- and dicalcium silicate. Hydroxyapatite deposits were evident on the surfaces of both materials in contact with HBSS. The pH of the leachate was similar for both materials. MTA-AW exhibited lower levels of calcium ions in solution and reduced fluid uptake in the early stages of reaction. The anti-washout gel reduced the setting time of the cement and enhanced the compressive strength. The radiopacity of both materials was approximately 8mm aluminum.
  
  
  CONCLUSIONS
  The use of the water-based anti-washout material instead of the standard water with MTA affects the hydration and properties of the set material.
authors.affiliation: Department of Metallurgy and Materials Engineering, Faculty of Engineering, University of Malta, Malta.
authors.forename: L M
authors.initials: LM
authors.lastname: Formosa
authors.forename: B
authors.initials: B
authors.lastname: Mallia
authors.forename: J
authors.initials: J
authors.lastname: Camilleri
mesh_terms: D017607:Aluminum Compounds / Q000737:chemistry*; D000704:Analysis of Variance; D017610:Calcium Compounds / Q000032:analysis* / Q000737:chemistry; D004338:Drug Combinations; D005782:Gels / Q000737:chemistry*; D006244:Hardness; D008855:Microscopy, Electron, Scanning; D010087:Oxides / Q000737:chemistry*; D016062:Porosity; D012387:Root Canal Filling Materials / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry*; D013052:Spectrometry, X-Ray Emission; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: D017607:Aluminum Compounds; D017610:Calcium Compounds; D004338:Drug Combinations; D005782:Gels; D010087:Oxides; D012387:Root Canal Filling Materials; D017640:Silicates; C086631:mineral trioxide aggregate