One Year Bond Strength Evolution of the Silorane Restorative System

Objectives: The aim of this study was to investigate the effect of long-term storage on the shear bond strengths (SBS) of the cationicly cured composite Filtek^TM Silorane (FS) with a volumetric shrinkage of less than 1%, and the Silorane System Adhesive (SSA) to bovine enamel and dentin.

Methods: Bovine incisors were embedded in cold-cure acrylic resin. The labial surface of each tooth was ground to expose enamel or dentin. A cylindrical button of FS (4.67mm diameter, 2mm height) was cured on the tooth surfaces treated with SSA according to the instructions for use (n=5). After storage intervals of 24h (baseline t=0) and 3, 6 and 12 months  in water at 37°C, the specimens were tested in shear mode using a Zwick Z010 universal testing machine (crosshead speed 2mm/min).

Results: The following table shows the SBS in MPa. The standard deviations (SD) are given in parentheses. All data were analyzed by ANOVA and multiple comparisons using Fisher's LSD procedure (p<0.05). Means with the same letters are statistically the same.

Storage time (months)	0	3	6	12
enamel	19,9 (1,9)a	19,6 (3,0)a	19,3 (3,6)a	20,7 (2,6)a,b
dentin	19,7 (2,7)a	23,4 (3,0)b,c	24,9 (2,3)b,c	24,0 (1,2)b,c

Conclusions: There was no statistically significant difference for the SBS of the Silorane System to enamel between t=0 and 12 months. SBS to dentin was significantly higher for t=12 months compared to baseline.