Clinical performance of Class II restorations in which resin composite is laminated over resin-modified glass-ionomer

This study evaluated the one-year functioning of resin-composite/resin-modified glass-ionomer open-laminate restorations when used for restoring Class II cavities. It also investigated the effect of the thickness of the resin composite layer on the performance of such restorations. The test restorations were made of Vitremer glass ionomer, Scotchbond Multipurpose Plus and Z100 resin composite, and the control restorations were made of Z100 with Scotchbond Multipurpose Plus. Forty pairs of restorations were placed in 40 patients aged 16 years and over. The thickness of the resin composite layer was measured both clinically and in the laboratory using a reflex microscope. The completed restorations were assessed in vivo and in vitro at baseline, six-month and one-year recalls using a modified Ryge system. The reflex microscope measurements showed that the majority of restorations had a resin composite layer of more than 1.5 mm in thickness, as intended. At one year, 37 pairs of restorations were examined. Apart from a few minor problems, all performed satisfactorily. Thus, it appears that the resin composite/resin modified glass ionomer open laminate is a suitable technique for restoring Class II cavities.