Evaluation of Microleakage in Class II Restorations with Flowable Composite and Fibers

Objectives: To compare and evaluate the effects of glass and polyethylene fibers with flowable composite and placement techniques on the microleakage in Class II cavities.
Methods: Class II slot cavities (randomized on mesial or distal surfaces, 4 mm width, 5 mm hight, 2mm depth) were prepared on 60 sound nonerupted human third molars. The cavities were bonded with Scotchbond MP etch-and-rinse adhesive (3M ESPE) and were randomly divided into 6 groups (n=10) according to the placement techniques: horizontal, oblique and 2 types of fibers: Glass Fiber (GF) (Ever Stick, StickTech), Polyethylene Fiber (PF) (Ribbond, Ribbond-THM). Filtek Ultimate Flow (FC) and Filtek Ultimate Universal nanohybrid composite (3M ESPE) were used to restore all cavities. In all groups cavities were lined with FC 1mm at the gingival seats as first increment. Groups 1 and 4: FC, Groups 2 and 5: GF inserted in to FC, Groups 3 and 6: PF inserted in to FC. For the placement techniques horizontal placement technique was used in the first 3 groups, oblique placement technique was used in the last 3 groups. The specimens were thermocycled (500x) and immersed in 50% silver nitrate solution for 24 hours. Microleakage on the gingival walls were evaluated with a stereomicroscope and calculated in the form of area after the application of decalcification and clearing method. Data were analyzed with Kruskal-Wallis and Mann-Whitney U-test (p<0.001).
Results: There were no significant differences between the placement techniques but less microleakage scores were determined by using oblique placement technique. The significant fewer microleakage scores were determined at the gingival seats in the groups which fibers inserted in to flowable composite were applied.
Conclusions: Microleakage was observed in all groups. Oblique placement technique may be used more secure. The usage of fibers combined with flowable composite were reduced microleakage.