Optical behavior and marginal discoloration of a single shade resin composite with a chameleon effect: a randomized controlled clinical trial

Evaluating the optical behavior and marginal discoloration of a Single-shade universal resin composite over 12 months. To achieve this, a split-mouth with a double-blinded randomized strategy was employed.

Twenty adult patients, each presenting with at least two caries lesions in their posterior teeth, were selected and randomly subdivided into two identical groups: Group I received Single-shade universal resin composite (Omnichroma), and Group II received multi-shade nanohybrid resin composite (Tetric®N-Ceram). Color measurements and marginal discoloration were assessed visually by three blinded operators at baseline followed after 1,3,6,9, and 12‑month periods utilizing the Modified United States Public Health Services (USPHS) criteria. Statistical analysis was adopted utilizing the Wilcoxon test with a 0.05 significance level.

The two groups revealed non-statistically significant differences up to 6 months regarding color match and color stability. After 9 and 12 months, the multi-shade group demonstrated a statistically significant higher prevalence of color match (Alpha) scores than the single-shade universal group. Regarding marginal discoloration, all restorations in the two groups had no discoloration (Alpha scores).

Since the percentage of Alpha and Bravo scores was considered clinical success, both the single-shade universal and the multi-shade nanohybrid resin composites demonstrated satisfactory optical performance and marginal discoloration as posterior restorations after a 12-month follow-up period.