title: Effect of obturating systems, dowel materials, and adhesive luting techniques on the resistance to fracture of endodontically treated teeth.
abstract: OBJECTIVE
  The aim of this study was to assess the role of obturating systems, dowel materials, and adhesive techniques on the resistance to fracture of endodontically treated teeth.
  
  
  METHODS
  Eighty maxillary central incisors were selected and randomly divided into two groups according to the obturating system (n = 40); group I: gutta-percha and Roeko sealer; group II: RealSeal. Both groups were further subdivided into two subgroups; subgroup A: using ceramic dowels (Cosmopost); subgroup B using fiber dowels (Easy Post). Each subgroup was assigned to two divisions according to the adhesive luting technique; division V (total-etch) Variolink II resin cement; division U (self-adhesive) RelyX Unicem. Composite core build-up was made using a core former. Each specimen was loaded 2 mm from its incisal edge on the palatal side at a 135° angle with the long axis of the tooth using a universal testing machine with a load cell of 5 KN at a crosshead speed of 0.5 mm/min until fracture. Failure loads were recorded in N. Scanning electron microscopic examination at the dentin/resin interface (1000x) was performed. Three-way ANOVA was used to test the effect of obturating system, dowel material, adhesive technique, and their interactions (obturating system * dowel material, obturating system * adhesive, dowel material * adhesive, obturating system * dowel material * adhesive). Duncan's test was used for pairwise comparison. The significance level was set at p≤ 0.05. Statistical analysis was performed with SPSS 16.0.
  
  
  RESULTS
  The mean resistance to fracture (617.4 N) was statistically significantly higher in the ceramic dowel with gutta-percha and Variolink (GP/C/V) group than in the other groups. The RealSeal and RelyX fiber dowel group's mean resistance was the lowest and was significantly lower than the other groups.
  
  
  CONCLUSIONS
  In this study, three factors played a part in enhancing the resistance to fracture of endodontically treated teeth. High resistance to fracture was achieved when ceramic dowels were luted with total-etch technique in gutta-percha-obturated teeth.
authors: Department of Fixed Prosthodontics, Faculty of Oral and Dental Medicine, Cairo University, Giza, Cairo, Egypt. dr_jul@hotmail.com
authors: Jylan
authors: J
authors: El Guindy
authors: Manar Y
authors: MY
authors: Fouda
mesh_terms: D000704:Analysis of Variance; D002484:Cementation; D002516:Ceramics; D003188:Composite Resins; D019232:Dental Restoration Failure; D003793:Dental Restoration, Permanent / Q000379:methods; D003799:Dental Stress Analysis; D006171:Gutta-Percha; D006801:Humans; D007180:Incisor; D008855:Microscopy, Electron, Scanning; D011176:Post and Core Technique; D019279:Resin Cements; D012387:Root Canal Filling Materials; D018709:Statistics, Nonparametric; D014082:Tooth Fractures / Q000517:prevention & control*; D019553:Tooth, Nonvital
chemical_list: D003188:Composite Resins; C511498:Real Seal composite resin; C483701:Rely X Unicem; D019279:Resin Cements; D012387:Root Canal Filling Materials; C103502:Variolink; D006171:Gutta-Percha