With the increasing demands of both esthetic and functional aspects of the dental restorative material, resin composite and adhesive technologies are rapidly evolving.
The incorporation of fiber into resin composite material stems from industrial demands for high-strength material that could withstand stress in load-bearing areas.
Consequently, short fiber-reinforced resin composite (SFRC) was introduced in 2013 as EverX Posterior (GC Corporation, Tokyo, Japan).
Multiple studies reported that this material showed superior mechanical properties compared to conventional resin composite in many aspects.
In recent years, further improvements have been made to improve the workability and handling properties of SFRC.
In 2019, flowable SFRC (EverX flow; GC Corporation, Tokyo, Japan) has been introduced, combining the advantage of fiber reinforcement and good flowability in the same material, by changing the length and diameter of the fibers, the content percentage of fiber, particulate fillers, and the resin matrix.
COMPOSITE RESTORATIONS: Simplified protocol for adjacent Class II direct resin restorations
Moreover, flowable SFRC could also be placed in bulk up to 5.5 mm according to the manufacturer, reducing technical sensitivities and chair-time for restoration of extensive cavities.
However, it is known that one of the problems of flowable resin composite is the polymerization shrinkage due to high monomer content. Flowable SFRC is not an exception.
An in vitro study found that, although flowable SFRC was superior to conventional bulk-fill resin composite in multiple aspects, such as flexural strength and fracture toughness, it exhibited more water sorption and polymerization shrinkage stress, which may lead to microleakage and post-operative sensitivity.
COMPOSITE RESINS: Restoration of fractured anterior tooth with monochrome composite resin in pediatric dental patient
In addition, it was shown that polymerization shrinkage stress tremendously weakened the performance and longevity of the restorations.
Even though there are numerous studies supporting SFRC superior properties, studies concerning flowable SFRC are still sparse.
Criteria regarding selection and use of contemporary class of restorative material is always of benefit.
Therefore, the objective of this study was to investigate the microleakage of class II cavities restored with SFRC compared to other resin composites, in a simulated aging environment using thermocycling.
