Comparison of color stability and fracture resistance of two temporary fiber‑reinforced fixed partial denture materials

Background: Temporary crown and bridge materials have to fulfill a couple of important functions within the timeframe between tooth preparations until luting of the definitive restoration. The aim of the current study was to evaluate the color stability and fracture resistance of two fiber‑reinforced provisional fixed partial denture (FPD) materials. Materials and Methods: In this in vitro study Using a plexiglass mold, 96 bar‑shaped specimens (4 mm × 2 mm × 20 mm) were fabricated and divided into four groups (n = 24): nonreinforced composite (NRC) resin, glass fiber‑reinforced composite resin (RC), nonreinforced polymethylmethacrylate (PMMA), and glass fiber‑reinforced PMMA. Values of CIEL*a*b* were recorded for all the samples. Then, the samples were immersed in coffee, chlorhexidine mouthrinse, and distilled water. After 1 day and 1 and 4 weeks, CIEL*a*b* values were recorded again and color differences (ΔE) were calculated. All the specimens immersed in distilled water were then subjected to force to measure their fracture resistance. Data were analyzed with one‑way ANOVA, honestly significant difference Tukey tests, and paired t‑test (α = 0.05). Results: The NRC group, immersed in coffee for 1 month, exhibited the highest ΔE (17.1 ± 0.69) and the lowest ΔE belonged to the RC group immersed in water for 1 day. The RC group, immersed in water, exhibited the highest fracture resistance. Conclusion: Coffee is considered as one of the most important factors affecting color changes in provisional FPDs, either in composite resins or in PMMAs. Fracture resistance of both composite resin and PMMA FPDs revealed no significant differences between the groups; however, there were significant differences between the nonreinforced and fiber‑reinforced FPDs in both groups.