Ferrule and Crown Affect Fracture Resistance of Endodontically Treated Teeth

Objectives:The purpose of this study was to compare the fracture resistance of endodontically treated (ETT) teeth restored with a resin composite with/without ferrule and with/without metal crown. Methods:Twenty four mandibular second premolars with similar dimension were divided into 4 groups (n=6); group 1 (crown with ferrule:C/F), group 2 (crown without ferrule:C/NF), group 3 (composite with ferrule:Co/F), and group 4 (composite without ferrule:Co/NF). Two millimeters of axial wall height was created for group with ferrule. The experimental fiber reinforced composite posts with glass fiber; parallel configuration, diameter 1.5 mm, E=18 GPa, was luted into the canal at the length of 10.5 mm using resin cement (Panavia F 2.0), cervical dentin was conditioned with self-etched adhesive (Clearlfil SE bond). The core was built-up with resin composite (Clearfil Photocore). For resin composite group, the coronal part was shaped to achieve 5 mm occluso-gingival dimensions and 45 degree bevel at buccal cusp was established. For crown group, a 0.8-mm-wide chamfer finishing line at the CEJ with a 4 mm occluso-gingival height was established. Metal crown with 1 mm of thickness was luted with resin cement (Panavia F2.0) to create the same dimension as non-crown group. A compressive load was applied on the beveled buccal cusp using a universal testing machine with a crosshead speed of 2 mm/min. The failure load was recorded in Newton and statistically analyzed with ANOVA. Results:The fracture resistances in Newton (SD) were 2543.01(360.57), 1624.4(264.20), 1411.15(147.42), and 1347.75(203.71), for group 1, 2, 3, and 4 respectively. Two-way ANOVA revealed significant differences on 2 main factors; final restoration and ferrule, and their interactions (P<0.05). Conclusions:Within the limitation of this study, it was concluded that C/F group presented with the highest fracture resistance compared to the others P<0.05.