title: Application of mercury intrusion porosimetry for studying the porosity of mineral trioxide aggregate at two different pH.
abstract: OBJECTIVE
  To evaluate a novel method of detecting and comparing the porosity of white Mineral Trioxide Aggregate and Portland cement at two different pH.
  
  
  METHODS
  Cylindrical specimens (n = 120) were prepared from hydrated ordinary white Portland Cement (WPC) (n = 60) and white Mineral Trioxide Aggregate (WMTA) (n = 60) and exposed to environments with pH of 4.4 (n = 30) or 7.4 (n = 30). The pore size distribution and total pore volume were detected using Mercury Intrusion Porosimetry. Data were analyzed by analysis of variance and post-hoc Tukey or Tamhane test (p = 0.05).
  
  
  RESULTS
  The pore volume of WMTA was significantly lesser than WPC at both pH (p < 0.05). The surface tension of mercury was taken as 480 (N/m) and the contact angle 141.3° for both materials. Pores were consistently found in all specimens. Total pore volumes for WPC and WMTA (cubic centimeter/gram) were 0.1954 and 0.1023, respectively, while the diameter of the pores ranged from 50-100 Å and 20-50 Å, respectively.
  
  
  CONCLUSIONS
  Mercury Intrusion Porosimetry technique is a promising and reliable technique for assessing the porosity of endodontic materials.
authors: Department of Dental Material, Dental School, Azad University, Dental Branch, Tehran, Iran. saghiri@gmail.com
authors: Mohammad Ali
authors: MA
authors: Saghiri
authors: Kamal
authors: K
authors: Asgar
authors: Mehrdad
authors: M
authors: Lotfi
authors: Kasra
authors: K
authors: Karamifar
authors: Prasanna
authors: P
authors: Neelakantan
authors: John L
authors: JL
authors: Ricci
mesh_terms: D017607:Aluminum Compounds; D017610:Calcium Compounds; D003738:Dental Cements; D003763:Dental Leakage / Q000517:prevention & control; D004338:Drug Combinations; D005240:Feasibility Studies; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing / Q000379:methods; D008628:Mercury / Q000737:chemistry*; D010087:Oxides; D010539:Permeability; D016062:Porosity; D012387:Root Canal Filling Materials; D017640:Silicates
chemical_list: D017607:Aluminum Compounds; D017610:Calcium Compounds; D003738:Dental Cements; D004338:Drug Combinations; D010087:Oxides; D012387:Root Canal Filling Materials; D017640:Silicates; C472247:accelerated Portland cement; C086631:mineral trioxide aggregate; D008628:Mercury