How do various mouth rinses influence the color stability of CAD-CAM resin-based restorative materials?

The color stability of computer-aided design and computer-aided manufacture (CAD-CAM) resin-based materials can be affected by their composition and exposure to different mouth rinses. However, the impact of different mouth rinse formulations on these materials remains unclear.

The purpose of this in vitro study was to investigate the effect of different mouth rinses on the color stability of CAD-CAM resin-based materials over time.

A total of 180 specimens of 5 CAD-CAM resin-based materials were fabricated: a polymer-infiltrated ceramic network (PICN) (Vita Enamic; ENA), resin nanoceramics (GC Cerasmart; CERA, Brilliant Crios; BRC), a resin nanohybrid (Grandio; GRD), and a resin composite (KZR-CAD HR2; KZR). A lithium disilicate ceramic (IPS e.max CAD; EMX) served as the control (n=30). Specimens were immersed in alcohol-containing (Listerine Cool Mint; LIS), alcohol-free (Oral-B complete; ORLB), zinc-chloride containing (Pharmol Zn; PHR), hypochlorous acid-containing (Briotech Pure; BRT) mouth rinses, and artificial saliva (CON) for 12 hours (t0.5), 2.5 days (t2.5), and 5 days (t5) of simulated exposure equivalent to 1, 5, and 10 years. Color differences (ΔE00) were calculated at each time point. The effects of material, mouth rinse, and time were analyzed using 3-way robust ANOVA with Bonferroni post hoc tests (α=.05).

EMX exhibited the highest color stability, while the GRD showed the largest discoloration (P<.001). LIS and ORLB mouth rinses caused significantly higher ΔE00 values than other solutions (P<.001). Discoloration increased with longer exposure times (P=.001). Among all groups, BRC immersed in LIS exhibited the most pronounced color change, while EMX in CON showed the least (P=.001).

CAD-CAM resin-based materials undergo a larger color change than lithium disilicate ceramic, with variations depending on composition and mouth rinse type. While alcohol-containing mouth rinse (LIS) induced the highest discoloration, particularly in the resin nanoceramic (BRC), the highest discoloration after a simulated prolonged exposure of 10 years was observed in the resin nanohybrid (GRD). Notably, the alcohol-free ORLB also led to significant discoloration, suggesting that other ingredients beyond alcohol contribute to staining.