title: Effect of powder-to-water ratio on the push-out bond strength of white mineral trioxide aggregate.
abstract: OBJECTIVE
  To evaluate the effect of powder-to-water ratio on the retention characteristics of white mineral trioxide aggregate (MTA; Angelus, Londrina, Pr, Brazil) over time.
  
  
  METHODS
  One hundred and thirty-five root dentin slices from extracted single-rooted human mandibular premolar teeth were instrumented to achieve a diameter of 1.3 mm. Three MTA groups were prepared using 4:1, 3:1, and 2:1 powder-to-water ratios. The samples were stored for 96 h and 7 and 28 days at 37°C. The push-out bond strengths were measured using an Instron testing machine. Data were analyzed using two-way analysis of variance (anova) with Bonferroni correction.
  
  
  RESULTS
  There was a statistically significant difference between the experimental groups at the 96-h and 7-day study periods (P = 0.002). At 96 h, the materials prepared at 2:1 ratio had the lowest bond strength than the samples prepared at the other two ratios (P < 0.001). There was a significant difference between the findings at 96-h and 28-day study periods for 2:1 and 4:1 ratios. The highest bond strength value was found at 28 days of exposure (P < 0.001).
  
  
  CONCLUSIONS
  The powder-to-water ratio significantly interfered with the bond strength properties of white MTA.
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Bülent Ecevit University, Zonguldak, Turkey.
authors.forename: Sevinç Aktemur
authors.initials: SA
authors.lastname: Türker
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Hacettepe University, Ankara, Turkey.
authors.forename: Emel
authors.initials: E
authors.lastname: Uzunoğlu
mesh_terms: D017607:Aluminum Compounds / Q000737:chemistry*; D001641:Bicuspid; D017610:Calcium Compounds / Q000737:chemistry*; D001840:Dental Bonding / Q000379:methods*; D018772:Dental Marginal Adaptation; D003799:Dental Stress Analysis; D004338:Drug Combinations; D006801:Humans; D066298:In Vitro Techniques; D008422:Materials Testing; D010087:Oxides / Q000737:chemistry*; D011208:Powders; D011897:Random Allocation; D012387:Root Canal Filling Materials / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry*; D014867:Water
chemical_list: D017607:Aluminum Compounds; D017610:Calcium Compounds; D004338:Drug Combinations; D010087:Oxides; D011208:Powders; D012387:Root Canal Filling Materials; D017640:Silicates; C086631:mineral trioxide aggregate; D014867:Water
keywords: bond strength; mineral trioxide aggregate; powder-to-water ratio