title: Effect of reduced post length on the resistance to fracture of crowned, endodontically treated teeth.
abstract: OBJECTIVE
  To examine the influence of a reduced post length sealed with a titanium-reinforced composite luting agent on the fracture resistance of crowned endodontically treated teeth with a 2-mm ferrule on healthy tooth structure.
  
  
  METHODS
  The study consisted of 60 intact single-rooted premolars with similar root diameters and lengths. Teeth were endodontically treated and randomly divided into 6 experimental groups (n = 10) with various post lengths (5, 8, and 10 mm) and types (ParaPost and Dentatus) of equal diameter. Posts were luted with a titanium-reinforced composite resin luting agent. Titanium-reinforced composite resin cores were constructed, and cast crowns with a 2-mm ferrule on healthy tooth structure were cemented. Specimens were mounted in a jig that allowed loading of the buccal cusp in the axio-occlusal line at a 30-degree angle to the long tooth axis. A continuous compressive force at a crosshead speed of 2 mm/min was applied by an Instron testing machine. Forces at fracture (in newtons) and mode of failure were recorded. One-way analysis of variance (ANOVA) and the Scheffe test were used to statistically compare the differences among groups at a significance of 5%.
  
  
  RESULTS
  ANOVA showed no statistically significant differences among the mean failure forces for the tested groups in their resistance to fracture under load. The Scheffé contrast test showed no statistically significant differences among all combinations of the 6 tested groups (F [5.59] = 0.032; P > .05).
  
  
  CONCLUSIONS
  Within the limitations of this study, post length did not influence the fracture resistance of crowned endodontically treated teeth with a 2-mm ferrule on healthy tooth structure. For tooth resistance, prosthesis design is more important than post characteristics.
authors.affiliation: Department of Prosthetic Dentistry, The Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Israel.
authors.forename: Joseph
authors.initials: J
authors.lastname: Nissan
authors.forename: Eitan
authors.initials: E
authors.lastname: Barnea
authors.forename: Daniela
authors.initials: D
authors.lastname: Carmon
authors.forename: Martin
authors.initials: M
authors.lastname: Gross
authors.forename: David
authors.initials: D
authors.lastname: Assif
mesh_terms: D000704:Analysis of Variance; D001641:Bicuspid; D003188:Composite Resins; D003738:Dental Cements; D017267:Dental Prosthesis Design; D003799:Dental Stress Analysis; D006801:Humans; D011176:Post and Core Technique; D019279:Resin Cements; D014025:Titanium; D014082:Tooth Fractures / Q000517:prevention & control*; D019553:Tooth, Nonvital
chemical_list: D003188:Composite Resins; D003738:Dental Cements; C101035:Flexi-Flow cement; D019279:Resin Cements; D014025:Titanium