Deep margin elevation with resin composite and resin-modified glass-ionomer on marginal sealing of CAD-CAM ceramic inlays: An in vitro study

Abstract

Purpose: To evaluate the marginal sealing ability of different restorative materials used in deep margin elevation (DME) on zirconia-reinforced lithium silicate CAD-CAM ceramic restorations.

Methods: A total of 30 Class II cavities were prepared in freshly extracted human molars with the proximal margin located 1 mm below the cemento-enamel junction (CEJ). All specimens were randomly assigned to one of three groups (n=10): control group, resin composite group (Filtek Z350 XT), and resin-modified glass-ionomer group (RMGI) (Vitremer Tricure). In Group 1, control group, no DME was performed. The inlay margin of the control group was placed directly on the dentin. In Groups 2 and 3, DME was used to elevate the margin to 1 mm above the CEJ with resin composite and RMGI, respectively. Zirconia-reinforced lithium silicate CAD-CAM ceramic restorations were manufactured and bonded on all specimens with universal bonding and resin luting cement. All specimens were aged by water storage for 6 months. Marginal sealing ability at different interfaces was evaluated with a stereomicroscope at 40x magnification by scoring the depth of silver nitrate penetrating along the adhesive surfaces. Statistical differences between groups were analyzed using the Kruskal-Wallis and Mann-Whitney U tests.

Results: At the dentin interface, there was no significant difference in microleakage scores in the control group and resin composite group (P= 0.577); however, the RMGI group had significantly higher microleakage compared to the control group (P= 0.004) and resin composite group (P= 0.007).

Clinical significance: Deep margin elevation can be achieved with resin composite. Resin-modified glass-ionomer must be used with caution due to the high microleakage scores.