Effect of three post types on fracture resistance of maxillary central incisors

Endodontically treated teeth, because of extensive structural defect, have the increased risk of fracture. For desirable reconstruction of coronal tooth structure, the post provide retention, nowadays non – metal post systems were introduced to dentistry. This study compared the fracture strength of maxillary central incisors restored with metallic, fiber composite and ceramic posts. Thirty human maxillary incisors were used in this invitro experimental study. The crown of each incisor was cut off 1 mm coronal to CEJ and perpendicular to the long axis of the tooth by metal disk. The root canals of the teeth were prepared for post after root canal therapy, then three groups of 10 specimen were formed. Teeth restored with Glass fiber, ceramic and prefabricated metallic posts and numbered as group 1, 2 and 3 respectively. Then, all teeth restored with composite core (Z100, 3M) and metal crowns were fabricated and cemented with glass ionomer vitremer luting cement. Specimens were embedded in autopolimerize acrylic resin 4 mm below ‍CEJ, and then secured in a universal testing machine. A compressive load was applied at 135 degrees angle to long axis with crosshead speed of 0.5 mm/min, till fracture occurred and fracture pattern was recorded. The data were collected and analyzed using ANOVA and LSD tests. Fracture resistance by Newton was respectively: 765±113.26, 790±95.34, and 614±105.32 for glass fiber posts, ceramic and metallic groups. Resistance to fracture for glass fiber and ceramic posts was significantly more than Titanium post (P<0.05), but there was no significant difference between glass fiber and ceramic posts. Considering the results, usage of prefabricated glass fiber and ceramic posts are more preferable than prefabricated titanium posts. Because of more undesirable fracture in ceramic posts group than glass fiber, glass fiber posts are recommended.