LAUSR

To investigate the long-term tooth discoloration induced by different hydraulic calcium silicate-based cements (HCSCs), depending on blood contamination and placement method in-vitro. Eighty bovine teeth, sliced to a length of 18 mm (crown 8 mm, root 10 mm), were randomly assigned to 10 groups (n = 8), receiving ortho- or retrograde apical plug treatment (APT). Apical plugs were 4 mm in length and made of ProRoot MTA (Dentsply), Medcem MTA (Medcem), TotalFill BC RRM Fast Set Putty (Brasseler), or Medcem Medical Portland Cement (Medcem) plus bismuth oxide (Bi2O3) with and without bovine blood. Orthograde (with or without preoperative adhesive coronal dentin sealing) and retrograde APT were compared. Teeth were root-filled with gutta-percha and sealer, adhesively restored, and stored in distilled water. Tooth color was measured on apical plug, gutta-percha/sealer, and crown surface before treatment, after 24 h, and up to 72 months after treatment by spectrophotometry. Color difference (ΔE) values were calculated and analyzed by ANOVA with post-hoc-tests, Shapiro-Wilk-test, Friedman-test, Mann-Whitney-U-test, t-test, and post-hoc-tests with Bonferroni correction (α = 0.05). The increase of tooth discoloration occurred in all groups with no significant differences between HCSCs (p >.05). After six years, color changes were strongly marked on roots but insignificant on crowns. The color differences on the measuring surface of the apical plug were statistically significant between 24 and 72 months (p <.001). Blood had a more relevant impact on tooth color than Bi2O3. There were no substantial long-term effects of retrograde placement (p >.05) or preoperative dentin sealing (p >.05). Apical plugs of the tested HCSCs cause ongoing discoloration of bovine roots, but no discoloration of bovine tooth crowns within a six-year period. Apical plugs should be carefully placed. If direct contact with the coronal dentin is avoided, long-term aesthetic impairments are unlikely to occur.