Effect of fiber posts on the fracture resistance of maxillary central incisors with Class III restorations: An in vitro study.

STATEMENT OF PROBLEM: Endodontically treated teeth with Class III restorations show reduced fracture resistance. The placement of glass fiber posts may affect fracture resistance and should be further evaluated.

PURPOSE: The purpose of this in vitro study was to evaluate the effect of fiber posts on the fracture resistance of endodontically treated maxillary central incisors with Class III restorations.

MATERIAL AND METHODS: Forty extracted human maxillary central incisors were selected and divided into 4 test groups (n=10 each) according to the restoration strategy: control group; endodontically treated teeth without endodontic posts (GHT); endodontically treated teeth with 2 Class III restorations simulating coronal destruction (GCT); endodontically treated teeth with 2 Class III restorations and a carbon fiber post (GCF); and endodontically treated teeth with 2 Class III restorations and a glass-fiber post (GGF). The fiber posts were adhesively cemented with composite resin cement, and the cavities were restored with composite resin. After 3 months of water storage, all specimens were loaded at 45 degrees in a universal testing machine until fracture and evaluated for fracture mode. The data were analyzed using 1-way ANOVA, followed by the Tukey honest significant difference multiple comparisons test (α=.05).

RESULTS: Mean ±SD failure loads ranged from 687.5 ±84.0 N to 943.8 ±93.1 N. One-way ANOVA revealed a statistically significant difference among the groups (P≤.05). The control group (GHT) had significantly higher resistance to fracture than the other groups (P≤.05).

CONCLUSIONS: Within the limitations of this in vitro study, placement of a fiber post did not affect the fracture resistance of endodontically treated maxillary central incisors with 2 Class III restorations.