Bond strength of repaired composite resins: surface treatments, adhesive systems, and composite type

The aim of the present study was to investigate the effects of three different surface treatments and two different adhesives on the microtensile bond strength (TBS) of repaired composites using the same or different type of resin. Twenty-four nano-hybrid (Ceram X mono-C) and 24 nanofilled (Filtek Ultimate-F) composite discs were prepared. The specimens were aged with 5000 thermocycles and randomly divided into groups according to the surface treatment methods: (a) phosphoric acid (b) Er:YAG laser and (c) aluminum trioxide particle (air abrasion). Fresh composite resins (C and F) were added to the treated surfaces with two different adhesives (two-step and one-step self-etch adhesives). Then, the specimens were aged again. The stick-shaped specimens were prepared from the discs (n=25) and the sticks were subjected to the TBS test. Results indicated that significant differences were found in TBS values among the surface treatment methods. In the C groups, the highest TBS value (41.3 +/- 8.3MPa) was recorded in the air abrasion and one-step self-etch adhesive group, which were repaired with the same kind of composite. In the F groups, the highest TBS value was observed in the air abrasion and one-step self-etch adhesive (37.6 +/- 12.3MPa) group. The treatment with air abrasion is more effective than the others, and it may be suggested for composite repair.