EVALUATION OF IMPACT OF LINING APPLICATION TECHNIQUES ON MARGINAL MICROLEAKAGE IN RESIN-MODIFIED GLASS IONOMER CEMENT IN CLASS II COMPOSITE RESTORATIONS: AN IN VITRO STUDY

Abstract

Aim of the study: The aim is to evaluate and compare marginal microleakage of class II resin composite restorations using a flowable composite and resin-modified glass-ionomer cement as intermediate layers, and to assess whether a difference in the thickness, consistency, and position of these layers would influence microleakage. Material and Methods: Forty-two extracted intacted molars were divided into six groups. Class II cavities in medial and distal parts were prepared. Cavities in Group A were lined with a flowable composite resin; Group B had no lining; in Group C1, the axial wall was covered with a 1.5 mm resin-modified glass-ionomer cement (RMGIC) layer; in Group C2, axial and gingival walls were covered with a 2.5 mm RMGIC layer; in Group C3, the axial wall was covered with a 1 mm RMGIC layer; and in Group C4, axial and gingival walls were covered with a 1 mm RMGIC layer. Results: No significant microleakage differences existed between groups A and B and the experimental group C3. In group C3, a low-viscosity RMGIC was applied only on the axial dentin wall of the cavity. Such difference, however, exists in comparison of group C1 or C2 with each of the groups A or B (p < 0.0001). The difference between groups C4 and A (p < 0.0001) was also significant. Conclusion: The least microleakage along the gingival walls of the model cavities with RMGIC occurs when a 1-mm layer of resin-modified glass-ionomer with fluid consistency covers only the axial wall of the proximal cavity.