Shear Bond Strengths Of Dentin Adhesives After 24 Hours And 6 Months H.Y. Chen*, J. Manhart, R. Hickel (Dept. Of Restorative Dentistry, LMU-University, Munich, Germany) Long-term bond strength data are more clinically relevant than bond strength values measured after 24 h storage of the specimens. This study determined dentin bond strength in shear mode of 8 adhesives after 24 h and 6 months storage. 128 human molars were ground (600-grit SiC) to expose a flat surface of superficial dentin and assigned to 16 groups (n = 8). Tetric Ceram was applied in 2 increments in a split PTFE mold with a bond diameter of 3 mm and bonded to the acid-etched dentin surface with 8 adhesives (1. Syntac Sprint = SS; 2. Onestep = OS; 3. Prime&Bond 2.1 = PB; 4. Optibond Solo = OP; 5. Singlebond = SB; 6. Tenure Quik = TQ; 7. Solobond M = SM; 8. Heliobond (control) = HB). Manufacturers' instructions were followed. Specimens were stored for 24 h and 6 months in water at 37°C and debonded in shear mode (crosshead speed 0.5 mm/min). Means and standard deviations of bond strengths (MPa) are listed. Data were analyzed by one-way ANOVA and post hoc Tukey tests at 24 h and 6 months. T-test was used for data analysis between 24 h and 6 months. Letters indicate statistically different subsets.     SS OS PB OP SB TQ SM HB 24 h 18.1 (2.7) c 23.5 (1.6) d 13.9 (3.3) c 24.7 (2.2) d 16.9 (1.8) c 6.6 (1.5) b 16.8 (2.5) c 1.4 (0.7) a 6 m 18.4 (3.4) d,e 21.8 (1.4) e,f 7.0 (2.4) b 25.2 (2.3) f 16.5 (2.4) c,d 18.0 (3.7) d,e 18.2 (3.4) d,e 0.3 (0.3) a   The results revealed statistically significant differences among the different adhesives after 24 h as well as 6 months storage (p=0.001). Bond strengths of TQ increased significantly with time. PB and the control HB showed statistically lower bond strength values after 6 months storage when compared to the 24 h data. Maintenance of bond strength values with time is dependent on the individual bonding systems.