title: Effect of a differently tilted angle of mandibular premolar on fracture resistance of 3 postcore restorations.
abstract: OBJECTIVE
  The objective of this study was to evaluate the effect of differently tilted mandibular premolars on fracture resistance of 3 postcore restorations.
  
  
  METHODS
  Seventy-five extracted human mandibular premolars were simulated to 5 different tilted angles: lingually tilted (LT) 30° and 15°, 0°, and buccally tilted (BT) 15° and 30°, and restored with custom-made metal postcore (CMPC), prefabricated fiber postcore (PFPC), or custom-made fiber postcore (CFPC). Then, a 30° oblique load was applied with a crosshead speed of 1 mm/min to the restoration. Failure loads and fracture modes were analyzed (2-way ANOVA and Tukey test, P < .05).
  
  
  RESULTS
  The buccally inclined restoration had higher fracture resistance than that of the lingually tilted restoration. The strength of the PFPC restoration was comparable with that of the CMPC restoration in all tilted groups. As for fracture modes, no significant differences were found among the various tilted restorations.
  
  
  CONCLUSIONS
  Buccally tilted mandibular premolars are more likely to be restored with prefabricated fiber postcore than a lingually inclined mandibular premolar.
authors: West China College of Stomatology, Sichuan University, Chengdu, China.
authors: Yongfu
authors: Y
authors: Hou
authors: Guotao
authors: G
authors: Wu
authors: Hai
authors: H
authors: Qing
authors: Zhimin
authors: Z
authors: Zhu