Methods: Adhesives tested were: (1) a two-step, etch and rinse GLUMA Comfort Bond (Heraeus Kulzer), (2) a two-step, self-etching CLEARFIL SE Bond (Kuraray) and (3) an all-in-one iBOND (Heraeus Kulzer). The resin composite Charisma (Heraeus Kulzer) build-ups were prepared on human dentin surface according to ISO/TS 11405. Twenty specimens manufactured for each adhesive were divided into two groups stored at 37° C. Group 1: Twenty-five applications of bleaching gel OPALESCENCE PF (20 % carbamide peroxide, Ultradent Products Inc.) on a composite-dentin margin within app. two months. Group 2: Two-month water storage (control). After the exposition the shear bond strength was measured using Bencor Multi T-device at a crosshead speed 0.75 mm/min (Shimadzu AGS-G). The fracture surfaces were analyzed by SEM. Data were statistically evaluated with t-test at p=0.05.
Results: Groups exposed to the bleaching gel showed significantly lower (p<0.003) shear bond strength than the control groups stored for two months in water.
Conclusion: Frequent application of peroxide bleaching gels may accelerate degradation of adhesive joints between a composite filling and dentin.
| Adhesive | Shear bond strength [MPa] | |
|---|---|---|
| Opalescence PF, twenty-five applications | water, two-month storage | |
| GLUMA Comfort Bond | 16.4 ± 6.6 | 24.1 ± 2.7 |
| CLEARFIL SE Bond | 22.0 ± 1.8 | 29.9 ± 3.9 |
| iBOND | 13.4 ± 2.3 | 20.0 ± 3.9 |
Supported by the Grant Agency of the Czech Ministry of Health, IGA MZCR NR/8278-3.