title: Investigation of a novel mechanically mixed mineral trioxide aggregate (MM-MTA(™) ).
abstract: OBJECTIVE
  To characterize a novel mechanically mixed mineral trioxide aggregate product (MM-MTA, MicroMega, Besançon, France) and to investigate the physical and chemical properties in comparison with ProRoot MTA (Dentsply, Tulsa Dental, Johnson City, TN, USA) and MTA Angelus (Angelus, Londrina, Brazil).
  
  
  METHODS
  The three materials were mixed according to manufacturer's instructions. Specimens 10 mm in diameter and 2 mm high were prepared and characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analysis after 1-day and 28-day storage in physiological solution. Calcium ion leaching in solution and pH of the elution were also assessed. Furthermore, the setting time, radiopacity and material porosity were investigated. Statistical analysis was performed by anova and Tukey's post hoc tests.
  
  
  RESULTS
  All the MTAs tested were composed primarily of tricalcium silicate and bismuth oxide. In addition, MM-MTA exhibited additional peaks for chlorine evident in the EDS analysis; calcium carbonate was present in the set material detected by XRD. Calcium hydroxide was present in the set ProRoot MTA and MTA Angelus. Calcium ion leaching and alkalization of the storage solution were demonstrated in all the materials. Both MM-MTA and MTA Angelus had a shorter setting time when compared to ProRoot MTA (P < 0.001). ProRoot MTA exhibited larger pores and more porosity than MTA Angelus and MM-MTA. All the materials exhibited radiopacity greater than the 3 mm aluminium thickness specified in ISO 6876 (2012).
  
  
  CONCLUSIONS
  MM-MTA, ProRoot MTA and MTA Angelus are composed of Portland cement and bismuth oxide. In addition, MM-MTA contains calcium carbonate and a chloride accelerator. These additives affect the material hydration and the properties of the set material. The properties of MM-MTA are a result of a combination of factors, namely the particular cement mineralogy, radiopacifier loading, effective water-cement ratio and mechanical mixing.
authors.affiliation: Department of Endodontics, Faculty of Dentistry, St Joseph University, Beirut, Lebanon.
authors.forename: I
authors.initials: I
authors.lastname: Khalil
authors.affiliation: Department of Endodontics, Faculty of Dentistry, St Joseph University, Beirut, Lebanon.
authors.forename: A
authors.initials: A
authors.lastname: Naaman
authors.affiliation: Department of Restorative Dentistry, Faculty of Dental Surgery, University of Malta, Msida, Malta.
authors.forename: J
authors.initials: J
authors.lastname: Camilleri
mesh_terms: D017607:Aluminum Compounds / Q000737:chemistry*; D001729:Bismuth / Q000737:chemistry*; D002118:Calcium / Q000737:chemistry; D017610:Calcium Compounds / Q000737:chemistry*; D004338:Drug Combinations; D004356:Drug Storage; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010087:Oxides / Q000737:chemistry*; D016062:Porosity; D017640:Silicates / Q000737:chemistry*; D013052:Spectrometry, X-Ray Emission; D014961:X-Ray Diffraction
chemical_list: D017607:Aluminum Compounds; D017610:Calcium Compounds; D004338:Drug Combinations; C475480:MTA-Angelus; D010087:Oxides; D017640:Silicates; C086631:mineral trioxide aggregate; D002118:Calcium; D001729:Bismuth
keywords: MM-MTA; MTA Angelus; ProRoot MTA; characterization; chemical properties; physical properties