title: Mechanical property characterization of a novel directly-placed ceramic restorative material.
abstract: OBJECTIVE
  To compare, in vitro, the mechanical properties of a directly-placed ceramic restorative material (Doxadent) to glass-ionomer (Fuji IX), hybrid composite control (Z250) and amalgam control (Tytin).
  
  
  METHODS
  Diametral tensile strength (DTS), compressive strength (CS), and Vickers hardness number (VHN) were measured for 10 specimens per group (n = 480 total) with time (1 hour, 24 hours, 1 week, 4 weeks). CS and DTS specimens were cylinders (4 x 8 mm). VHN specimens were disks (9.5 x 1 mm). Specimens were prepared following manufacturers' instructions, stored in deionized water (37 degrees C), and tested in 100% humidity (23 degrees C). CS and DTS specimens were loaded to failure (Instron, CHS = 0.5 mm/minute). VHN discs were indented. Data were analyzed using ANOVAand Tukey's test (P < 0.05) for pairwise comparisons of group means at each time.
  
  
  RESULTS
  In CS and DTS, DoxaDent was weakest (P < 0.05) for all testing times except Fuji IX DTS at 1- and 4-week intervals. For VHN, DoxaDent was harder than glass-ionomer, better than composite except at 1 hour and less than amalgam. Except for VHN for Z250, all values improved from 1-24 hours. Based on current in vitro results, this novel restorative material does not yet equal composite or amalgam CS or DTS.
authors.affiliation: Department of Operative Dentistry, University of North Carolina at Chapel Hill, School of Dentistry, 413 Brauer Hall, CB# 7450, Chapel Hill, NC 27599-7450, USA. jonas@akranes.com
authors.forename: Jónas
authors.initials: J
authors.lastname: Geirsson
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Bayne
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Swift
authors.forename: Jeffrey Y
authors.initials: JY
authors.lastname: Thompson
mesh_terms: D017607:Aluminum Compounds / Q000737:chemistry*; D017610:Calcium Compounds / Q000737:chemistry*; D002516:Ceramics / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry; D019245:Compressive Strength; D003722:Dental Alloys / Q000737:chemistry; D003723:Dental Amalgam / Q000737:chemistry; D003738:Dental Cements / Q000737:chemistry*; D003793:Dental Restoration, Permanent; D005899:Glass Ionomer Cements / Q000737:chemistry; D006244:Hardness; D006801:Humans; D008422:Materials Testing; D013314:Stress, Mechanical; D013718:Tensile Strength; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D017607:Aluminum Compounds; D017610:Calcium Compounds; D003188:Composite Resins; D003722:Dental Alloys; D003738:Dental Cements; C462459:DoxaDent; C444701:Filtek Z250; D005899:Glass Ionomer Cements; C110713:fuji IX; D014867:Water; C036886:tytin; D003723:Dental Amalgam