Evaluation of Gingival Microleakage in Deep Class II Closed Sandwich Composite Restoration: An In vitro Study

Abstract

Introduction: Microleakage is a major problem beneath deep Class II composite restorations where little or no enamel remains. One technique to overcome this problem is sandwich restoration in which an intermediate liner is sandwiched between tooth and composite restoration. Aim: This study evaluated and compared gingival microleakage at tooth restoration interface in deep Class II composite closed sandwich restorations (mesio-occlusal) using different liners like Resin Modified Glass Ionomer Cement (RMGIC), Biodentine, Theracal LC. Materials and Methods: Standardised conventional mesioocclusal cavities were prepared on 40 extracted maxillary first premolars with dimension 2 mm buccolingually and the gingival seat placed at the level of cementoenamel junction. Teeth were divided into four groups (n=10). In Group 1 (control group) cavities were restored with composite (Filtek 250) using self etch bonding agent (scotch bond). In Group 2, 3 and 4, 0.8 mm thick liner of RMGIC, Biodentine and Theracal LC were applied respectively on the axial wall of the cavity. All the cavities were then restored with composite using self-etch bonding agent similar to Group 1. The specimens were then immersed in 0.5% aqueous solution of rhodamine B dye for 24 hours, sectioned and observed for the extent of dye penetration using confocal laser scanning microscope. Statistical analysis was performed using Kruskal-Wallis test for intergroup comparison followed by Mann-Whitney test for intragroup comparison. Results: Microleakage scores indicated that use of a liner beneath deep Class II composite restorations significantly reduced microleakage. Among the liners used, Biodentine and Theracal LC showed better results than RMGIC. Conclusion: This study concluded that use of a liner beneath deep Class II composite restoration reduced microleakage and Theracal LC performed similar to Biodentine and better than RMGIC, when used as a liner in deep Class II composite closed sandwich restorations.

Keywords

• caries
• confocal laser scanning microscope
• polymerisation shrinkage