Staining of dental composite resins with chlorhexidine mouthwashes

Objective. The purpose of this in vitro study was to evaluate staining of 4 dental composite resins, two microfilled and two nanofilled, exposed to different chlorhexidine mouthwashes. Materials and methods. The composite resins (Esthet-X, Gradia Direct, Ceram-X Mono, and Filtek Supreme XT) were polymerized into 120 plastic rings (height 2 mm; internal diameter 4 mm; external diameter 6 mm) to obtain identical specimens. The specimens were subjected to 2 chlorhexidine mouthwashes (Corsodyl 0.2% and Curasept ADS 0.2%), one of those containing an antidiscoloration system. The specimens were dipped for 1 minute, twice at day (every 12 hours), for 15 days into the mouthwash and into distilled water (as control). Color of specimens was measured with a spectrophotometer according to the CIE L*a*b* system after light-polymerization of composite resin specimens, after 7 days and after 14 days of treatment with chlorhexidine. The color differences (ΔEab*) between each measurement were calculated. Analysis of variance (ANOVA) was used to analyze the data. Results. All specimens showed a significant progressive increase in staining with increasing number of rinsing in all chlorhexidine mouthwashes, with a similar trend and no significant differences between microfilled and nanofilled composite resins. Significance. Microfilled and nanofilled composite resins had similar in vitro discoloration in both 0.2% chlorhexidine mouthwashes. Chlorhexidine mouthwash with anti discoloration system stained the evaluated composite resins in the same way as conventional 0.2% chlorhexidine mouthwash.