title: The effect of human blood on the setting and surface micro-hardness of calcium silicate cements.
abstract: OBJECTIVE
  The purpose of the present study was to evaluate the effects of human blood on the setting and microhardness of calcium silicate cements.
  
  
  METHODS
  Three types of silicate-based cements were used: ProRoot MTA (PMTA), OrthoMTA (OMTA), and RetroMTA (RMTA). Mixed cement was placed into polyethylene molds with lengths of 2 and 4 mm. After storage for 4 days under three different storage conditions, i.e., saline, saline after 5 min of human blood, and human blood, the polyethylene molds were removed. With the specimens set, the surface microhardness was measured using a Vickers microhardness tester, crystalline structure was analyzed with X-ray diffraction (XRD), and the surface characteristics were examined with scanning electron microscopy (SEM).
  
  
  RESULTS
  All specimens of 4 mm in length were set with all materials, and the blood groups exhibited lower microhardnesses than did the saline groups (p < 0.05). Among the 2-mm specimens that were stored in blood, the numbers of specimens that set were significantly different across the materials (p < 0.001). Regarding the microhardnesses of the RMTA and OMTA groups, there were no significant differences between storage conditions. For the PMTA group, only one specimen that was set in the blood group exhibited reduced microhardness. XRD showed changes of crystalline structure in the PMTA and OMTA blood group, whereas RMTA did not. SEM analysis revealed more rounded and homogeneous structures and demonstrated a clear lack of acicular or needle-like crystals in the PMTA and OMTA blood groups, while RMTA did not reveal substantial differences between the saline- and blood-stored groups.
  
  
  CONCLUSIONS
  Blood contamination detrimentally affected the surface microhardnesses of all materials; furthermore, among the 2-mm specimens, blood contamination interfered with normal setting. Therefore, RMTA might be a more suitable choice when blood contamination is unavoidable due to limited depth. Clinical relevance RetroMTA might be a more suitable choice in situations in which blood contamination is unavoidable.
authors.affiliation: Division of Constitutive & Regenerative Sciences Section of Restorative Dentistry, UCLA School of Dentistry, Los Angeles, CA, USA.
authors.forename: Minju
authors.initials: M
authors.lastname: Song
authors.affiliation: Microscope Center, Department of Conservative Dentistry and Oral Science Research Center, College of Dentistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, South Korea.
authors.forename: Wonyoung
authors.initials: W
authors.lastname: Yue
authors.affiliation: College of Dentistry, Yonsei University, Seoul, South Korea.
authors.forename: Soyeon
authors.initials: S
authors.lastname: Kim
authors.affiliation: College of Dentistry, Yonsei University, Seoul, South Korea.
authors.forename: Wooksung
authors.initials: W
authors.lastname: Kim
authors.affiliation: College of Dentistry, Yonsei University, Seoul, South Korea.
authors.forename: Yaelim
authors.initials: Y
authors.lastname: Kim
authors.affiliation: College of Dentistry, Yonsei University, Seoul, South Korea.
authors.forename: Jeong-Woong
authors.initials: JW
authors.lastname: Kim
authors.affiliation: Microscope Center, Department of Conservative Dentistry and Oral Science Research Center, College of Dentistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, South Korea. ANDYENDO@yuhs.ac.
authors.forename: Euiseong
authors.initials: E
authors.lastname: Kim
mesh_terms: D017607:Aluminum Compounds; D001769:Blood; D017610:Calcium Compounds; D004338:Drug Combinations; D006245:Hardness Tests; D006801:Humans; D008855:Microscopy, Electron, Scanning; D010087:Oxides; D012387:Root Canal Filling Materials / Q000737:chemistry*; D012823:Silicate Cement / Q000737:chemistry*; D017640:Silicates; D012965:Sodium Chloride; D013499:Surface Properties; D014961:X-Ray Diffraction
chemical_list: D017607:Aluminum Compounds; D017610:Calcium Compounds; D004338:Drug Combinations; D010087:Oxides; D012387:Root Canal Filling Materials; D017640:Silicates; C086631:mineral trioxide aggregate; D012823:Silicate Cement; D012965:Sodium Chloride; C031293:calcium silicate
keywords: Calcium silicate cements; Human blood; Micro-hardness; Mineral trioxide aggregate; RetroMTA