OBJECTIVE: The aim of this study was to compare the fracture resistance of endodontically treated maxillary central incisors with irregular crown ferrule effect after static loading.
MATERIAL AND METHODS: Forty maxillary central incisors were divided into 4 groups (n=10). Endodontic treatment was performed. Teeth were decoronated 3.5 mm above the
cemento-enamel junction (CEJ). Group I (control) had uniform 2mm long axial wall. Group II had length of labial axial wall reduced by 1mm. Group III had length of palatal axial wall reduced by 1mm. Group IV had no coronal dentine 1.5 mm above CEJ. The teeth received fiber reinforced posts and composite core restorations. Metal crowns were cemented with
type I glass ionomer cement. The restored teeth samples were loaded on a universal testing machine for fracture testing. The results were subjected to one way ANOVA and HSD TUKEY test to analyze the statistical significance.
RESULTS: The mean fracture load values (N) were, Group I 535.29N, Group II 657.34N, group III 426.2N, and group IV 362.6N. Analysis revealed Group II was statistically significant from Group IV (p0.000), Group III (p0.000) and Group I (p0.081).
CONCLUSIONS: Uniform ferrule effect and Labial irregular
ferrule effect increased the failure threshold. Palatal axial wall had profound effect on fracture resistance and in the absence of uniform 2mm axial wall, maximum 2mm palatal
axial wall with minimum 1mm labial axial wall increased the fracture resistance. Insertion of a fiber post could reduce the percentage of catastrophic failure
