title: The effect of luting agent on the fracture resistance of root canal treated teeth restored with casting post.
abstract: BACKGROUND
  The aim of this study was to determine the effect of different luting agents on fracture resistance of endodontically treated teeth restored with casting post.
  
  
  METHODS
  In this experimental study, forty extracted human maxillary central incisors teeth with the mean length of 23mm were randomly assigned in to four groups. All the studied teeth were caries free without any crack. After root canal treatment, the specimens were stored in 100% relative humidity at 37°C for 72h, and were decoronated 2mm above cementoenamel junction. The teeth in group1, 2, 3, and 4 received casting post and core and they were cemented with Zinc phosphate, Panavia F, Fuji Glass Ionomer, and Rely X, respectively. All teeth received 1.5 mm shoulder finishing line and 0.5mm bevel. Samples were then restored with complete coverage crowns and were loaded with an Instron universal testing machine. The cross-head speed was 0/02 cm/min and specimens were loaded with load values (Newton) computed at a speed of 1000 point/min, until the fracture happened. Loads were applied with 135 degree at middle lingual surfaces of the samples. Fracture loads were recorded. Data were analyzed by the one-way ANOVA test.
  
  
  RESULTS
  There was no significant difference between the fracture resistances of four test groups.
  
  
  CONCLUSIONS
  According to the results of this in vitro study, the type of luting cement had no influence on the fracture resistance of teeth.
authors.affiliation: Department of Prostodontics, Dental School, Shahed University, Tehran, Iran.
authors.forename: Sayed Shojaedin
authors.initials: SS
authors.lastname: Shayegh
authors.affiliation: Department of Endodontics, Dental School, Shahed University, Tehran, Iran.
authors.forename: Kiumars
authors.initials: K
authors.lastname: Nazari Moghaddam
authors.affiliation: Department of Operative Dentistry, Dental School, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Khoroshy
authors.affiliation: Department of Material Engineering, Isfahan University of Technology, Isfahan, Iran.
authors.forename: Froogh
authors.initials: F
authors.lastname: Khoroshy
keywords: Casting Post; Fracture Strength; Luting Cement