title: Effect of 1-piece post and core fabrication techniques on fracture strength.
abstract: OBJECTIVE
  The purpose of this in vitro study was to evaluate and compare the fracture strengths of post and core systems produced with different fabrication techniques and materials.
  
  
  METHODS
  Forty extracted human single-root premolars were used in this study. After root canal treatment, the teeth were randomly divided into 4 groups of 10 each as follows: group C: metallic 1-piece posts and cores fabricated by casting, and serving as the control; group CM: metallic posts and cores fabricated with the copy milled technique; group LS: 1-piece posts and cores fabricated with the laser sintering technique; and group ZR: 1-piece zirconia posts and cores fabricated with computer-aided design and computer-aided manufacturing (CAD-CAM). The posts and cores were cemented to the teeth with adhesive resin cement; then, the specimens were mounted to acrylic resin blocks, attached to an Instron Universal Testing Machine, and loaded with a crosshead speed of 1 mm/min, until fracture. Data were statistically analyzed using 1-way analysis of variance (ANOVA), followed by the post hoc Tukey test (α = 0.05).
  
  
  RESULTS
  The highest fracture results were found in group ZR (315.4 ± 53.4 N), which showed significant differences from all other groups (p&lt;0.05). The lowest test values were found in group C (230.2 ± 29.8 N). Group LS (250.9 ± 29.0 N), group CM (253.0 ± 22.4 N) and group C did not show any significant differences (p&gt;0.05).
  
  
  CONCLUSIONS
  Custom-made zirconia 1-piece posts and cores, fabricated using the CAD-CAM procedure, can be an alternative treatment method when compared with other techniques.
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Ondokuz Mayis University, Samsun - Turkey.
authors.forename: Elif
authors.initials: E
authors.lastname: Kalyoncuoğlu
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Ondokuz Mayis University, Samsun - Turkey.
authors.forename: Çağrı
authors.initials: Ç
authors.lastname: Ural
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Ondokuz Mayis University, Samsun - Turkey.
authors.forename: Hikmet
authors.initials: H
authors.lastname: Aydemir
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Ondokuz Mayis University, Samsun - Turkey.
authors.forename: Muhammed Ali
authors.initials: MA
authors.lastname: Aslan
authors.affiliation: Private Practice, Samsun - Turkey.
authors.forename: Veysel
authors.initials: V
authors.lastname: Balkaya
mesh_terms: D017076:Computer-Aided Design; D003786:Dental Pulp Cavity / Q000502:physiology*; D006801:Humans; D008422:Materials Testing; D012387:Root Canal Filling Materials / Q000737:chemistry*; D019553:Tooth, Nonvital / Q000503:physiopathology*; D015040:Zirconium / Q000737:chemistry
chemical_list: D012387:Root Canal Filling Materials; D015040:Zirconium