Effects of Various Solutions on Color Stability and Surface Hardness of Nanohybrid Dental Composite Under Simulated Oral Conditions

Aim: This study evaluated effects of various solutions on color stability and surface hardness of a nanohybrid dental composite in simulated oral environments. Materials and methods: Sixty-four composite disks were fabricated and randomly allocated into eight groups (n = 8 per group): Artificial saliva (AS), Biotene (B), passion fruit juice (PFJ), orange juice (OJ), Sprite (S), Coca-Cola (CO), apple cider vinegar (ACV), and cranberry juice (CJ). Specimens were immersed in respective solutions at 37°C for 28 days. Surface microhardness was assessed using Vickers microhardness test, and color alterations were quantified using SpectroShade Micro spectrophotometer. Measurements were taken 24 hours after initial polymerization and after 28-day immersion period. Statistical analysis was performed using mixed model ANOVA. Results: After 28 days, specimens exhibited significant changes in microhardness and color. Polished surfaces showed microhardness decreases of 21.9–35.5%, with ACV and CJ causing largest reductions. Non-polished surfaces unexpectedly showed increased microhardness (11.2–17.4%). Color changes were more pronounced on polished surfaces, with CO and CJ causing maximum alterations. Statistical analysis revealed significant interactions between surface treatment, staining media, and immersion time (p < 0.05). Conclusion: All experimental groups demonstrated significant changes, highlighting composite materials’ susceptibility to environmental factors. Even well-polymerized and polished surfaces underwent alterations, emphasizing necessity for periodic follow-up and maintenance polishing in esthetic restorations. Clinical significance: The present research emphasizes significance of oral environmental factors on composite restoration longevity and esthetics, advocating for patient education on dietary impacts and tailored maintenance strategies to preserve restoration quality.