<>Objectives: Intraoral repair of fractured veneer may prevent the total replacement of the restoration. This study tested the repair bond strength and bond failure probability of restorative composite to aged fiber-reinforced composite (FRC).
Methods: Polymethylmethacrylate and dimethacrylate monomer preimpregnated unidirectional FRC (everStick, StickTech ) adhesion substrates were aged by boiling 8 h and storing at 37°C water for 6 weeks. The aged substrate surfaces were wet-ground (1200-grit) and subjected to different surface treatments together with an intermediate resin (IMR) (3M Multipurpose resin, 3M-ESPE): 1) An adhesion primer (Composite Activator, Bisco) and IMR, 2) Silane (EspeSil, 3M-ESPE) and IMR, 3) Silane, adhesive primer and resin (Clearfill Repair, Kuraray) 4) Silicate particle-abrading (CoJet, 3M-ESPE), silane (EspeSil) and IMR, 5) Only IMR (control). Composite resin (Z250, 3M-ESPE) adherend (diameter 3.6mm, height 4mm) was added to the substrate and light cured. The specimens (n=12 /group) were either 48 h water-stored or thermocycled (6000 x 55-5ēC). The shear bond strengths of composite resin to FRC was measured with a crosshead speed of 1.0 mm/min.
Results: ANOVA showed significant difference between the groups (p<0.05). Bond strength increased significantly after thermocycling (p<0.05) . Weibull analysis revealed highest weibull modulus for silica- particle-abrading group after thermocycling.
| | Bond strength (MPa) Mean (SD) | Weibull modulus |
| Group | Waterstorage | Thermocycled | Water storage | Thermocycled |
| Composite Activator+resin | 11.9 (6.5) | 8.5 (4.9) | 2.09 | 0.64 |
| Espesil+resin | 19.1 (9.2) | 23.8 (9.0) | 1.61 | 2.39 |
| Clearfill Repair | 29.6 (7.4) | 35.6 (7.5) | 4.09 | 4.46 |
| CoJet +silane+resin | 29.1(11.4) | 42.2 (7.4) | 2.91 | 6.04 |
| Resin (control) | 10.4 (4.1) | 10.0 (5.2) | 2.61 | 2.42 |