Connective Forces between Layers of Filtek^TM Silorane versus Methacrylate Composites

Objectives: Aim of this study was to investigate the connective forces between layers of the cationic cure filling composite Filtek^TM Silorane (FS), 3M ESPE, with a volumetric shrinkage of less than 1% versus those for conventional methacrylate based composites (Filtek^TM Supreme XT (FSXT), 3M ESPE; Tetric EvoCeram (TEC), Ivoclar Vivadent).

Methods: A first layer of composite was placed in a cavity (9mm diameter, 2.5mm depth) in a cold-cure acrylic resin block and cured according to the instructions for use. A cylindrical button of the same material (4.67mm diameter, 2mm height) was cured on the first layer (n=10). After a storage time of 24h 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 connective forces between layers 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.

Material	FS	FSXT	TEC
Connective Forces (MPa)	18.3 (1.8)a	20.7 (1.8)b	18.8 (1.7)a

Conclusions: There was no statistically significant difference for the connective forces between layers of  FS versus TEC. FSXT had significantly higher connective forces than the other materials.