The Radiopacity and Antimicrobial Properties of Different Radiopaque Double Antibiotic Pastes Used in Regenerative Endodontics.

Introduction: We evaluated the radiopacity and antibacterial properties of various concentrations of double antibiotic paste (DAP) containing barium sulfate (BaSO) or zirconium oxide (ZrO) radiopaque agents.

Methods: The radiopacity of 1, 10, and 25 mg/mL DAP containing 30% (w/v) BaSO or ZrO, DAP-free radiopaque pastes, and commercially available radiopaque calcium hydroxide (Ca[OH]) were evaluated according to ISO 6876/2001 with slight modifications (n = 6 per group). Dentin samples (n = 70) infected anaerobically for 3 weeks with bacterial biofilms obtained from a root canal of an immature tooth with pulpal necrosis were treated with similar experimental pastes or received no treatment (n = 7). After 1 week, the pastes were rinsed off, and biofilm disruption assays were conducted. To show the residual antibacterial effects, sterile dentin samples (n = 70) were pretreated for 1 week with the same pastes (n = 7). The pastes were rinsed off, and the samples were immersed in phosphate-buffered saline for 24 hours and infected anaerobically with the same bacterial biofilm mentioned earlier for 3 weeks before conducting biofilm disruption assays. Sterile dentin blocks were used in both antibacterial analyses as negative control groups (n = 7). Wilcoxon rank sum tests were used for statistical analyses.

Results: No tested concentrations of BaSO DAP or ZrO DAP showed significant differences from Ca(OH) in radiopacity. However, all tested concentrations of BaSO DAP, ZrO DAP, and Ca(OH) exhibited significant direct antibacterial effects. ZrO DAP at 1 mg/mL and Ca(OH) did not show significant residual antibacterial effects.

Conclusions: BaSO DAP at 1 mg/mL provided significantly superior residual antibacterial effects and comparable radiopacity with the commercially available Ca(OH).