Impact of Anti-Discoloration System (ADS) on the Optical Stability of Alkasite and Composite Resins: A Comparative Study on the Synergistic Staining Effect of Chlorhexidine and Coffee.

This study investigated the impact of conventional chlorhexidine (CHX) and anti-discoloration system (ADS)-containing CHX mouthrinses on the color stability of diverse dental polymers, both alone and in combination with coffee. Specimens (n = 180) were prepared from a nanohybrid composite (Charisma Diamond; Kulzer GmbH, Hanau, Germany), a monochromatic composite (Vittra Unique APS; FGM Dental Group, Joinville, Brazil), and a dual-cure alkasite (Cention Forte; Ivoclar Vivadent, Schaan, Liechtenstein). Following a 14-day cycle of mouthrinse immersion (2 min/daily) and coffee exposure (15 min/daily at 85 °C), color changes (ΔE00) were analyzed using the CIEDE2000 system. All materials exhibited significant discoloration across all protocols (p < 0.001). Cention Forte showed the highest susceptibility to staining, particularly in the CHX + coffee group (ΔE00 = 21.10), while Charisma Diamond remained the most stable (0.95-8.60). Conventional CHX (Kloroben; Drogsan Pharmaceuticals, Ankara, Turkey) induced significantly higher staining than ADS-CHX (Curasept ADS; Curasept S.p.A., Saronno, Italy) across all materials (p < 0.05). Notably, ADS technology significantly inhibited coffee-induced pigmentation in Cention Forte (p = 0.003) and Charisma Diamond (p = 0.046), effectively reducing the synergistic staining layer. In conclusion, while coffee consumption dramatically increases discoloration following CHX use, ADS technology serves as a protective barrier, reducing pigment adhesion. For patients with high dietary pigment intake, ADS-containing mouthrinses offer a significant clinical advantage in preserving the aesthetic longevity of polymeric restorations.