Methods: A total of 40 Spectrum TPH, 40 Restorative Z100 and 40 Point-4 resin discs (4mm in diameter and 2mm thick) cured against a Hawe transparent strip were secured in stainless steel rings, using self-curing acrylic resin. The specimens were divided into four groups of 10 each and surface treated as follows: A: no treatment, B: coarse Sof-Lex, C: air abrasion (50mm Al2O3, 50 psi, 2,5 seconds and at 14 mm distance) and D: coarse diamond bur (100-120 µm grit). All the specimens were then treated with Prompt-L-Pop bonding agent Pertac II stubs (3,18 mm in diameter and 2 mm high) were bonded to the surface-treated discs, using a rubber mould. The resin material was placed in the mould and light-cured for 60 seconds. After removal of the mould the stubs were again light-cured for 60 seconds and stored in distilled water for 24 hours at 37°C. The specimens were stressed to failure in an Instron Materials Testing Machine.
Results: Shear bond strengths (MPa):
| Shear bond strengths (MPa) for the various surface-roughening procedures | |||||
| Substrate | Bonding Composite | A | B | C | D |
| Spectrum TPH Restorative Z100 Point-4 | Pertac II Pertac II Pertac II | 2,7367 2,0704 3,6140 | 9,3086 6,0283 4,7503 | 7,3064 6,5421 6,2892 | 10,1994 8,5224 6,3175 |
Conclusions: The shear bond strengths of the self-etching primer-adhesive treated substrate surfaces were, except for Pertac II bonded to Point-4, significantly increased (p ≤ 0,05) by the different surface roughening procedures.