Potential Crown Discoloration Induced by the Combination of Various Intracanal Medicaments and Scaffolds Applied in Regenerative Endodontic Therapy

Regenerative endodontics involves the use of various root canal medicaments and scaffolds, which may cause crown discoloration. This study aimed to investigate the combined crown discoloration of scaffolds [platelet-rich fibrin (PRF) and blood clot] applied after administration of different medicaments [modified triple antibiotic paste including doxycycline (mTAPd), modified double antibiotic paste (mDAP), calcium hydroxide (CH), and propolis]. In total, 100 human mandibular premolar teeth were selected and prepared. The teeth were apically resected to simulate immature teeth. The positive and negative control groups (n = 10) consisted solely of blood-only and serum-only samples. The remaining 80 teeth were used for the experimental groups with four different medicaments. Three weeks later, either blood or PRF was applied as a scaffold after removing the medicaments (n = 10). Color changes were assessed before medication placement and at the end of the first, second, and third weeks, as well as on days 0, 1, 30, 60, and 90 after scaffold application. Analysis was carried out using repeated measures of variance, Friedman, one-way ANOVA, Kruskal-Wallis, the dependent paired t-test, and Wilcoxon test. Statistical significance was determined at P = 0.05. All groups including blood and the group including propolis and PRF combination, resulted in a significant increase in discoloration (P < 0.05) and discoloration exceeding clinically acceptable thresholds. CH and the modified versions of TAP (mTAPd) and DAP (mDAP) demonstrated an acceptable level of discoloration when used with a combination of PRF at day 90.