Marginal integrity of partial ceramic crowns within dentin with different luting techniques and materials

Area of Science:

• Dental Materials Science
• Restorative Dentistry
• Biomaterials Engineering

Background:

• Partial ceramic crowns (PCCs) are widely used for restoring posterior teeth.
• Ensuring excellent marginal integrity and sealing is crucial for the longevity of PCC restorations.
• Conventional luting techniques and newer resin-coating methods require comparative evaluation for optimal clinical outcomes.

Purpose of the Study:

• To evaluate and compare the marginal integrity of PCCs using conventional luting, a resin-coating luting technique, and a self-adhesive universal resin cement.
• To assess microleakage at ceramic/composite, resin-coating/composite, and dentin/composite interfaces after simulated clinical stress.
• To determine the effectiveness of resin-coating in improving marginal sealing compared to conventional methods.

Main Methods:

• An in vitro study involving 84 extracted human molars prepared for PCCs with margins 1 mm below the cemento-enamel junction.
• PCCs fabricated from Vita Mark II ceramic using Cerec-3.
• Three luting groups: conventional (Variolink II, Panavia-F2.0), resin-coating (Variolink II with Tetric Flow, Panavia-F2.0 with Clearfil SE-Bond), and self-adhesive universal resin cement (RelyX Unicem).
• Specimens subjected to thermocycling and mechanical loading, followed by silver staining assessment for microleakage.

Main Results:

• The resin-coating luting technique showed improved marginal integrity at the dentin interface (18-53% microleakage) compared to the conventional luting technique (58-67% microleakage).
• RelyX Unicem, the self-adhesive universal resin cement, exhibited the lowest microleakage values (15%) across all tested interfaces.
• Material selection significantly influenced marginal sealing performance in both conventional and resin-coating groups.

Conclusions:

• Resin-coating techniques may enhance marginal sealing at the dentin interface for partial ceramic crowns, contingent upon the specific materials employed.
• Self-adhesive universal resin cements provide superior marginal sealing compared to both conventional and resin-coating luting techniques evaluated in this study.
• Further clinical investigations are warranted to validate the long-term efficacy of these luting strategies in vivo.