Impact of PVM/MA Copolymer on Dentin Bond Durability.

OBJECTIVES

This study investigated the effect of Polymethyl vinyl ether-co-maleic anhydride (PVM/MA) copolymer incorporation and aging with thermocycling on the shear bond strength (SBS) of an etch-and-rinse adhesive (Adper Single Bond Plus-ASB) and two different self-etch adhesive systems (Clearfil SE Bond-CSE and Fluorobond II-FLB) to dentin.

MATERIALS AND

METHODS

Adhesive systems were applied to 240 dentin sections randomly selected from the occlusal surfaces of 60 extracted molar teeth. The test groups were as follows (n=20): (G1) Pure Clearfil SE (CSE) Bond; (G2) CSE with copolymer (50 mg/ml PVM/MA); (G3) Pure FL II Bond (FLB); (G4) FLB with copolymer (50 mg/ml PVM/MA); (G5) Pure Adper Single Bond (ASB); and (G6) ASB with copolymer (50 mg/ml PVM/MA). A resin composite (Clearfil Majesty Posterior) was applied to the dentin surfaces and light-cured. Half of the specimens from each group were tested immediately after preparation (IM) and the other half was tested after exposure to 20,000 thermal cycles (TC; 5-55 °C). SBS values were measured at a crosshead speed of 0.5 mm/min. Data were analyzed with ANOVA and Tukey's HSD.

RESULTS

The PVM/MA copolymer incorporation improved the performance of CSE in the IM group and ASB in the TC group, however, it showed no influence in the other adhesive groups. The self-etch adhesive CSE with the PVM/MA copolymer showed the highest bond strength to dentin surfaces in the IM group (22.0±1.7 MPa). However, copolymer corporation did not increase bonding performance of Fluor containing bonding agent FLB. Thermocycling of test specimens significantly decreased bond strengths in all test groups except for ASB resin adhesive with PVM/MA copolymer.

CONCLUSION

Incorporating PVM/MA into ethanol-based, hydrophilic all-in-one bonding agents may offer a valuable strategy to improve the long-term stability of adhesive systems.