Evaluating the effects of bleaching on color stability and surface roughness in single-shade and multi-shade resin composites

Aims: This study aimed to evaluate the effects of aging and bleaching procedures on the color stability and surface roughness of single-shade composite resins and compare them with a multi-shade composite resin. Methods: Fifty composite resin specimens (n=10 per group) from five brands— Omnichroma (Tokuyama, Japan) (OMN), Zenchroma (President Dental, Germany) (ZNC), Charisma Diamond One (Kulzer, Germany) (CHR), Essentia Universal (GC Corporation, Japan) (ESU) and one multi-shade composite resin Filtek Z550 (3M ESPE, USA) (FLT), —were subjected to aging (1-year simulated staining and brushing) and bleaching procedures. Color measurements were taken at baseline, after aging, and after bleaching using a spectrophotometer, while surface roughness was measured using a contact mode profilometer. Data were analyzed using Generalized Linear Models and Tukey’s test for multiple comparison, with a significance level set at p