Influence of the interposition of transparent filler silicone matrix on the color stability of conventional and fluid composite resins

Objective– To evaluate the color stability of two composite resins under different light-curing times and the use of transparent silicone matrices of varying thicknesses from two brands (Silic One Clear Body – FGM, Brazil; Elite Transparent – Zhermarck, Italy). Material and Methods– A total of 120 disc-shaped specimens (6 mm × 1.5 mm) were prepared, with 60 specimens each for Opallis Flow A3 and Opallis EA3 (FGM, Brazil). Specimens were divided into three groups based on matrix use: no matrix (control), Silic One Clear Body, and Elite Transparent (n = 20/group). Two polymerization protocols were applied: 20 s and 20 s + 20 s (or 40 s and 40 s + 20 s) (n = 10). Color measurements were taken at baseline and after 15 days using the CIEL a b* system and a reflection spectrophotometer (UV-2600, Shimadzu). Statistical analysis included Levene and Shapiro-Wilk tests (p ≤ 0.05). Results– No significant differences were observed between the resins, except when the flowable resin was polymerized for 40 s using the Elite matrix. Additional curing (+ 20 s) improved the color stability of the flowable resin in this condition. Conclusion– Both conventional and flowable resins showed similar color stability. However, flowable resin may require extended curing time when used with the Elite Transparent matrix to enhance stability. Clinical Relevance– Color stability can be influenced by the matrix type and curing protocol. For flowable resins, extended light-curing is recommended when using the Elite matrix to ensure long-term esthetic results.