“INJECTABLE Resin Composite” for Long-Lasting Aesthetic Restorations

Objectives: Resin composite is a widely used direct restorative material, because of its ease of use, great aesthetics, and cost effectiveness. Resin composites with different viscosities are required to fit in all cavity types. They are generally classified into flowable, and packable types, based on their viscosity.
We have introduced INJECTABLE type as a new category of resin composite which has both viscosity suitable for direct filling and favorable mechanical properties.
In this study, the mechanical and the discoloration resistance properties of resin composites were investigated.
Methods: G-aenial Universal Injectable (GUI), Omnichroma Flow (OCF), Filtek Supreme Flowable Restorative (FSF), Omnichroma (OC), Filtek Universal Restorative (FUR) and Admira Fusion 5 (AF5) were evaluated.
For flexural strength evaluation, specimens were prepared and test was implemented in accordance with ISO4049:2019.
To evaluate discoloration properties, specimens were prepared by filling each material in a mold (φ10mm x 1mm height), light-cured with G-light Prima II Plus (GC Corp.), and polished with SiC paper (#1000). Then they were immersed in red wine at 37 °C for 1 week.
The colors of each specimen before and after the immersion were measured with spectrophotometer (SD 7000, Nippon Denshoku), and color changes (ΔE*ab) were calculated (n=5). The results were statistically analyzed by one-way ANOVA followed by Tukey’s HDR test (p<0.05).
Results: Average of Flexural strength/ΔE*ab are shown in the table.
GUI had equivalent flexural strength to FUR, and the highest discoloration resistance among the tested products.
It was considered that GUI achieved high mechanical and discoloration resistance properties by improving the filler surface treatment process. In general, the discoloration is related to monomer components. GUI is composed of monomer with less hydrophilic functional groups such as Bis-MEPP while other products contain the monomers having hydrophilic functional groups such as UDMA and/or Bis-GMA.
Conclusions: GUI had equivalent flexural strength to packable type FUR and showed the highest discoloration resistance among the tested products. Therefore, GUI as an INJECTABLE resin composite, can be a clinical favorable choice for long-lasting aesthetic restorations including occlusal surfaces.