Influence of glass fiber posts and class III direct restorations on the resistance of anterior teeth

Abstract

This study objectives to evaluate the fracture strength of upper central incisors (UCI) restored with composite resin (CR) in Class III cavities and endodontically treated teeth with or without glass fiber post (GFP), analyzing their failure mode. Sixty human UCI were randomly divided into four experimental groups: endodontically treated teeth without GFP (G1), endodontically treated teeth with GFP (G2), teeth with mesial/distal Class III cavities restored with CR without GFP (G3), and teeth with mesial/distal Class III cavities restored with CR with GFP (G4). The samples were submitted to the fracture strength test in a universal testing machine with a compression shear load applied at speed of 1.0 mm/min until fracture occurred. The data were submitted to one-way ANOVA (α=0.05) and the samples were analyzed for failure mode. The analysis did not show a significant statistical difference in fracture strength between the groups (p>0.05). The results showed that only endodontically treated teeth (G1) (753.4N) presented behavior similar to teeth with GFP (G2) (702.1N). The same occurred when comparing teeth with Class III cavities without GFP (G3) (670.2 N) and with GFP (G4) (746.1N). It can be concluded that glass fiber posts do not change the fracture strength of incisors with endodontic treatment and Class III cavities.