title: Evaluation of the effect of blood contamination on the compressive strength of MTA modified with hydration accelerators.
abstract: OBJECTIVE
  This study was performed to evaluate the effect of blood contamination on the compressive strength (CS) of Root MTA (RMTA) modified with Calcium chloride (CaCl2) and Disodium hydrogen phosphate (Na2HPO4) as setting accelerators over time.
  
  
  METHODS
  A total of 110 cylindrical specimens of RMTA were divided into 6 experimental groups as follows: Group1, RMTA; Group 2, RMTA modified with CaCl2 (RMTA-C); Group 3, RMTA modified with Na2HPO4 (RMTA-N); Group 4, RMTA contaminated with blood; Group 5, RMTA-C contaminated with blood; Group 6, RMTA-N contaminated with blood. The CS of specimens in all groups was evaluated after 3 hr, 24 hr, and 1 wk. In the modified groups (groups 2, 3, 5, and 6) the CS of five specimens per group was also evaluated after 1 hr.
  
  
  RESULTS
  Blood contamination significantly reduced the CS of all materials at all time intervals (p < 0.05). After 3 hr, the CS of specimens in the RMTA groups (with and without blood contamination) was significantly lower than those in the RMTA-C and RMTA-N groups (p < 0.05). The CS values were not significantly different at the other time intervals. In all groups, the CS of specimens significantly increased over time (p < 0.05).
  
  
  CONCLUSIONS
  Blood contamination decreased the CS of both original and accelerated RMTA.
authors.affiliation: Department of Endodontics, Tehran University of Medical Sciences School of Dentistry, Tehran, Iran.
authors.forename: Kaveh
authors.initials: K
authors.lastname: Oloomi
authors.forename: Eshaghali
authors.initials: E
authors.lastname: Saberi
authors.forename: Hadi
authors.initials: H
authors.lastname: Mokhtari
authors.forename: Hamid Reza
authors.initials: HR
authors.lastname: Mokhtari Zonouzi
authors.forename: Ali
authors.initials: A
authors.lastname: Nosrat
authors.forename: Mohammad Hossein
authors.initials: MH
authors.lastname: Nekoofar
authors.forename: Paul Michael Howell
authors.initials: PM
authors.lastname: Dummer
keywords: Blood contamination; Calcium chloride; Compressive strength; Disodium hydrogen phosphate; Mineral trioxide aggregate