Effect of Application Phase of Different Adhesive Systems on Coronal Discoloration Caused by Endoseal MTA: An In-vitro Study

Objectives: This in-vitro study evaluated the effect of different application phases of dentin bonding agents (DBA) on preventing crown discoloration caused by a calcium silicate-based root canal sealer. Materials and Methods: Samples were divided into three main groups: Pre-preparation, Pre-obturation, and Pre-preparation/Pre-obturation, with each group further divided based on adhesive systems. DBA was applied before irrigation in the Pre-preparation, after irrigation in the Pre-obturation, and both before and after irrigation in the Pre-preparation/Pre-obturation groups. After applying the sealer, color measurements were recorded at baseline (T0), 1 month (T1), and 6 months (T2). Results: Findings showed that application phase, evaluation period and the interaction between these factors significantly affected discoloration. The lowest color change was observed between T1-T0, with significant differences between evaluation periods. The highest color change occurred in the Pre-preparation and control groups at T2-T0 compared to other groups. However, all groups showed color changes above the clinical acceptability (>1.8) and perceptibility thresholds (>0.8). Conclusion: The application phase of DBA and evaluation period significantly influenced crown discoloration, with the greatest changes observed during the pre-preparation phase, emphasizing the critical role of procedural timing in minimizing aesthetic impacts.