Fracture resistance of reattached incisor fragments with mini fibre-reinforced composite anchors

Abstract

Objectives Fractured coronal fragments of incisors can be adhered to the remaining tooth with resin composite, but are prone to failure. This study explores whether mini fibre-reinforced composite (FRC) anchors increase fracture resistance of reattached fragments. Methods Forty-five extracted incisors were randomly divided into three groups. In Groups A and B coronal fragments were reattached to the remaining tooth, with additionally two anchors placed in Group B. In Group C resin composite buildups were made. Specimens were statically loaded until failure occurred. Failure modes were characterized as intact remaining tooth substrate (adhesive or cohesive failure of coronal fragment) or fractured remaining tooth substrate (fracture limited to enamel or extending into dentin). Results Mean fracture loads were 255 N (SD = 108 N) for Group A, 599 N (SD = 465 N) for Group B and 786 N (SD = 197 N) for Group C (values significantly different, all p values <0.05). Group A showed purely adhesive failures, while Groups B and C showed 73 and 53% fractures of remaining tooth substrate ( p < 0.05). Conclusions Mini FRC anchors increase fracture resistance of reattached coronal fragments, but induce more remaining tooth substrate fractures.