Color adjustment of single-shade composites following staining, repolishing, and bleaching procedures.

Objective: This in vitro study aimed to assess the color adjustment level of single-shade composites following staining/repolishing and bleaching procedures.

Materials and methods: Cervical cavities in two depths (1 mm and 2 mm) were restored. Three single-shade composites (Omnichroma, OM; Essentia Universal, EU; and Charisma DiamondOne, CDO) and one group-shade composite (NeoSpectraST, NEO) were used (n = 10 for each). Following the thermal aging, half of the restorations were subjected to staining and repolishing procedures, while the other half were subjected to bleaching procedures. The color adjustments between restoration and adjacent tooth surfaces were assessed. The deemed significance was set at < 0.050.

Results: According to the initial measurements, the NEO composite presented the lowest ∆E₀₀ while the OM presented the highest (P = .005 and P = .014). Single-shade composites presented similar and clinically acceptable ∆E₀₀ values (P ≥ .050; AT ≤ 1.8). After the staining, the ∆E₀₀ of the OM was higher among the other single-shade composites (P = .001). Repolishing procedure decreased only the ∆E₀₀ of the NEO composite (P = .020). The bleaching procedure provided no difference for the single-shade composites (P ≥ .050). The increase in the cavity depth decreased the initial color adjustments for the OM in both repolishing and bleaching groups (P = .041 and P = .047).

Conclusions: Re-polishing after aging and staining may not enhance the single-shade composites' color adjustment level, unlike the group-shade composites. Good color adjustment might be predicted for the single-shade composites after bleaching, unlike the group-shade composites. The effect of the cavity depth was considered composite brand dependent.

Clinical significance: Clinicians should understand the color adjustment behaviors of the single-shade composites well after different clinical procedures such as staining, re-polishing, and bleaching to perform a proper restorative treatment plan and to obtain better esthetic outcomes.