Fracture Resistance of Reattached Tooth Fragments: Influence of Adhesive Curing Mode and Composite Viscosity

To evaluate the influence of adhesive curing mode and composite viscosity type on the fracture resistance of reattached anterior teeth using the internal groove technique.

Seventy-two extracted human maxillary central incisors were fractured using a standardized protocol and randomly assigned to six groups according to adhesive curing mode (light-cure, self-cure, and dual-cure) and composite viscosity type (flowable and packable) (n = 12). Fragments were reattached using standardized procedures. All specimens were subjected to thermocycling (5000 cycles) and fracture resistance was measured using a universal testing machine. Fracture resistance recovery (%) was calculated. Data were analyzed using two-way ANOVA and Tukey post hoc tests (α = 0.05).

Both adhesive curing mode and composite viscosity type significantly influenced fracture resistance (p < 0.001), while no significant interaction between factors was observed (p > 0.05). The highest fracture resistance recovery was observed in the dual-cure packable group, whereas the lowest values were recorded in the light-cure flowable group. Packable composites demonstrated higher fracture resistance than flowable composites across all adhesive curing modes.

Dual-cure adhesives combined with packable composites demonstrated the highest fracture resistance, whereas light-cure adhesives with flowable composites demonstrated the lowest values.

Dual-cure adhesives combined with packable composites demonstrated higher fracture resistance in fragment reattachment procedures.