Durability of One-step Adhesives to both Enamel and Dentine

Methods: 18 extracted molar teeth were equally divided into two groups. One group had their crowns horizontally sectioned to expose superficial dentine, which was then ground with 600 grit SiC paper. One of three one-step adhesives; a trial bonding agent, OBF-2 (Tokuyama Dental Corp.), i Bond (Heraeus kulzer), or Adper Promt L-Pop (3M Espe) was applied to the dentine of 3 teeth and built up with composite resin. The other group had their enamel approximal surfaces ground with 600 grit SiC paper. One of three one-step adhesives; OBF-2, i Bond, or Adper Prompt L-Pop was applied to the enamel of 3 teeth and built up with composite resin. All the teeth were then sliced perpendicular to the bonded interface into 0.7 mm-thick slabs. After 24 hours and 1 year of water storage, 2 slabs from each group were transversely sectioned into beams (maximum 15 per group), approximately 0.7x 0.8 mm, for the microtensile bond strength test. Data (mean ± SD, MPa), were analyzed using the Kaplan-Meier non-parametric analysis and Cox`s proportional hazard model to estimate the effects of bonding system, substrate and time (p<0.05).

Results:

DENTINE

1 DAY OBF-2 43.9 ± 9.4, i Bond 38.8 ± 12.5, Adper Prompt L-PoP 36.7 ± 16.8

1 YEAR OBF-2 33.4 ± 16.1, i Bond 30.5 ± 10.6, Adper Prompt L-PoP 29.5 ± 13.3

ENAMEL

1 DAY OBF-2 25.3 ± 9.4, i Bond 17.9 ± 8.8, Adper Prompt L-Pop 23.5 ± 13.7

1 YEAR OBF-2 15.5 ± 6.9, i Bond 13.9 ± 12.1, Adper Prompt L-Pop 16.1 ± 8.5

Conclusion: The bond strengths of the three adhesives to both enamel and dentine significantly reduced after one year of water storage, however, there was no significant difference between the materials.