title: Effect of different ferrule designs on the fracture resistance and failure pattern of endodontically treated teeth restored with fiber posts and all-ceramic crowns.
abstract: OBJECTIVE
  This study investigated the effect of different ferrule heights on endodontically treated premolars.
  
  
  METHODS
  Fifty sound mandibular first premolars were endodontically treated and then restored with 7-mm fiber post (FRC Postec Plus #1 Ivoclar-Vivadent) luted with self-polymerized resin cement (Multilink, Ivoclar Vivadent) while the coronal section was restored with hybrid composite core build-up material (Tetric Ceram, Ivoclar-Vivadent), which received all-ceramic crown. Different ferrule heights were investigated: 1-mm circumferential ferrule without post and core (group 1 used as control), a circumferential 1-mm ferrule (group 2), non-uniform ferrule 2-mm buccally and 1-mm lingually (group 3), non-uniform ferrule 3-mm buccally and 2-mm lingually (group 4), and finally no ferrule preparation (group 5). The fracture load and failure pattern of the tested groups were investigated by applying axial load to the ceramic crowns (n=10). Data were analyzed statistically by one-way ANOVA and Tukey's post-hoc test was used for pair-wise comparisons (α=0.05).
  
  
  RESULTS
  There were no significant differences among the failure load of all tested groups (P<0.780). The control group had the lowest fracture resistance (891.43 ± 202.22 N) and the highest catastrophic failure rate (P<0.05). Compared to the control group, the use of fiber post reduced the percentage of catastrophic failure while increasing the ferrule height did not influence the fracture resistance of the restored specimens.
  
  
  CONCLUSIONS
  Within the limitations of this study, increasing the ferrule length did not influence the fracture resistance of endodontically treated teeth restored with glass ceramic crowns. Insertion of a fiber post could reduce the percentage of catastrophic failure of these restorations under function.
authors: Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia.
authors: Haneef
authors: H
authors: Sherfudhin
authors: Joseph
authors: J
authors: Hobeich
authors: Carlos Augusto
authors: CA
authors: Carvalho
authors: Moustafa N
authors: MN
authors: Aboushelib
authors: Walid
authors: W
authors: Sadig
authors: Ziad
authors: Z
authors: Salameh
mesh_terms: D000704:Analysis of Variance; D019245:Compressive Strength; D003442:Crowns; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D005898:Glass; D006801:Humans; D008422:Materials Testing; D011176:Post and Core Technique; D019279:Resin Cements; D014082:Tooth Fractures; D019553:Tooth, Nonvital
chemical_list: D019279:Resin Cements