INTRODUCTION: One of the main causes of composite replacement is its discoloration after prolonged exposure to the oral environment. In an effort to fulfill the patient esthetic desire, harmonize composite material have been introduced with limited studies regarding its esthetic properties and color stability.
OBJECTIVES: To study the effect of coffee on the color stability of two nanohybrid composites with different monomers.
MATERIALS AND METHODS: The resin composites tested were Venus diamond and Harmonize. A custom made disk-shaped mold (4mm thickness x 8 mm diameter) used to prepare 12 composite specimens. They were divided into 2 groups (n=6) according to the resin based composite that was used as follow: Group A restored with Urethane dimethacrylate based composite (Venus diamond, Heraeus Kulzer) and Group B restored with Bisphenol A diglycidil dimethacrylate based composite (Harmonize, Kerr). The specimens were finished using (Multi fluted tungsten carbide finishing bur for fifteen seconds) followed by polishing using (HiLuster, Kerr) polishing system. After that, the specimens were immersed in coffee solution for 7 days. Color difference ΔE was calculated before and after immersion of specimens for 48 hours and after 7 days using spectrophotometer (VITA easy shade).
RESULTS: Mann Whitney U test showed significant difference in ΔE among composite restorative materials (p < 0.05). Venus diamond composite resin was found to be more stain-resistant than Harmonize composite resin after both 48 hours and 7 days.
CONCLUSION: Different monomer compositions, immersion time and solution may have direct effect on the color stability of nanohybrid restorative materials.