title: Surface microhardness of different thicknesses of a premixed bioceramic material with or without the application of a moist cotton pellet.
abstract: BACKGROUND
  This study was conducted to assess the effect of thickness and hydration condition on the surface microhardness of Endosequence Root Repair Material putty (ERRM; Brasseler USA, Savannah, GA), a premixed bioceramic material.
  
  
  METHODS
  Polymethyl methacrylate cylindrical molds with an internal diameter of 4 mm and three heights of 2, 4, and 6 mm were fabricated. In Group 1 (dry condition), the molds with heights of 2, 4, and 6 mm (10 molds of each) were filled with ERRM. In Groups 2 and 3 (wet condition), a distilled water- or phosphate-buffered saline (PBS)-moistened cotton pellet was placed directly on the upper surface of ERRM, respectively. The lower surface of ERRM was in contact with floral foams soaked with human blood. After 4 days, Vickers microhardness of the upper surface of ERRM was tested. The data were analyzed using two-way analysis of variance. Significance level was set at P < 0.05.
  
  
  RESULTS
  No significant difference was found between the microhardness of three thicknesses of ERRM (2, 4, and 6 mm) with or without placing a distilled water- or PBS-moistened cotton pellet over the material (P > 0.05).
  
  
  CONCLUSIONS
  Based on the results of this study, it could be concluded that placing a moistened cotton pellet on ERRM putty up to 6 mm thick might be unnecessary to improve its surface microhardness and hydration characteristics.
authors.affiliation: Department of Endodontics, Dental Research Center, Dentistry Research Institute, Tehran, Iran.
authors.forename: Noushin
authors.initials: N
authors.lastname: Shokouhinejad
authors.affiliation: Department of Endodontics, Dental Research Center, Dentistry Research Institute, Tehran, Iran.
authors.forename: Hassan
authors.initials: H
authors.lastname: Razmi
authors.affiliation: Department of Endodontics, Dental Research Center, Dentistry Research Institute, Tehran, Iran.
authors.forename: Mehrfam
authors.initials: M
authors.lastname: Khoshkhounejad
authors.affiliation: Department of Oral and Maxillofacial Surgery, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Arezoo
authors.initials: A
authors.lastname: Javani
authors.affiliation: Department of Endodontics, Laboratory of Molecular Neuroscience, Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Raoof
keywords: Dry; hardness; pellet; phosphate-buffered saline; root repair; silicates; wet condition