Fracture mechanics of dental adhesives supplemented with Polymethyl-vinyl-ether-co-maleic anhydride

The objective of this study was to determine the effect of Polymethyl-vinyl-ether-co-maleic anhydride (PVM/MA), called Gantrez AN, on interfacial fracture toughness (KIC) of self-etch and etch-and-rinse dental adhesives. Sixty-five chevron-notched dentin-composite resin specimens were prepared. The following testing groups with different bonding agents were prepared and tested with a cross head speed of 0.1 mm/min: Clearfil SE (CF); Clearfil SE with Gantrez AN in primer (CFGp); Clearfil SE with Gantrez AN in bonding agent (CFG); Prime & Bond (PB); Prime & Bond with Gantrez AN (PBG). The KIC values were determined and compared. The mode of failure was examined with light microscopy. The mean KIC (standard deviation) of the Clearfil SE groups were 0.60 (0.09) MPa m1/2 for CF, 0.64 (0.09) MPa m1/2 for CFGp and 0.68 (0.16) MPa m1/2 for CFG. The most common mode of fracture was cohesive. The mean KIC (standard deviation) of the Prime & Bond groups were 0.63 (0.09) MPa m1/2 for PB and 0.41 (0.11) MPa m1/2 for PBG. Adhesive fracture most commonly occurred in the Prime & Bond groups. Gantrez AN did not adversely affect KIC of the self-etch dental adhesive, but lowered KIC of the etch-and-rinse adhesive. Addition of Gantrez AN to self-etch adhesive (CF) may be warranted to produce an antibacterial effect. Clinical studies of bacterial attachment and anti-bacterial effects to further justify the use of Gantrez AN in bonding agents are warranted.