The Effect of Fluid Composite as Gingival Layer on Microleakage of Class II Composite Restorations

Abstract

Introduction
Fluid composites have been suggested as gingival layer beneath class II composite restorations to improve marginal integrity and reduce microleakage. This in-vitro study evaluated the influence of fluid composites as gingival layer on microleakage of class II packable, microhy-brid, and fiber-reinforced composite restorations with the margins below the cementoenamel junc-tion (CEJ).

Methods and Materials
45 sound premolars extracted for orthodontic reasons were selected. Class II cavities were prepared on the mesial and distal aspects with the gingival margin placed 1 mm be-low the CEJ, making 90 slot cavities. Teeth were randomly assigned into 3 groups (n=15). In each group, one side of each tooth was restored incrementally with respective packable, microhybrid, and fiber-reinforced composites; whereas, on the other side, fluid composite was placed as a 1 mm thickness gingival increment before restoration with the same composites. The teeth were stored for one week in distilled water at 37ْ C, thermo-cycled (5-55ْ C, x 1500), and immersed in 0.5% basic fuchsine for 24 hours. Dye penetration was evaluated using a stereomicroscope at 10x magnification. The data were analyzed statistically by Kruskal-Wallis analysis of variance and Mann-Whitney U-test.

Results
The fluid composite reduced microleakage at gingival margins of Class II restorations (P<0.05). The packable composite -with or without fluid composite- showed lower microleakage, whereas microhybrid and fiber-reinforced composites without fluid composite, showed higher mi-croleakage.

Discussion
The fluid composite significantly decreased the microleakage at gingival margins of Class II composite restorations.

Key Words
Microleakage, Posterior Composite, Packable Composite, Fiber-reinforced Composite, Fluid Composite, Microhybrid Composite.