In vitro comparison of the physical properties of zinc oxide eugenol-based, propolis-containing experimental root canal sealers with standard sealers

Objective: To compare the physical properties and microleakage of zinc oxide eugenol-based experimental sealers containing propolis (PS) with Grossman sealer and AH Plus. Materials and Method: Propolis collected from Tekirda？ area (Thrace region, Turkey) was used. Experimental sealers containing propolis at different ratios were prepared [5% (PS5), 10% (PS10), 25% (PS25), 50% (PS50)], and compared with Grossman sealer and AH Plus. The film thickness, flow, radioopacity, setting time, solubility and pH of the aqueous extracts were evaluated according to the ISO 6876/2001 standards. The microleakage was evaluated using the computerized fluid filtration method. Friedman and Kruskal-Wallis tests were used for the statistical analysis of the pH and the remaining data, respectively (α=0.05). Results: Except for the solubility, the physical properties of the PSs were compatible with the ISO 6876/2001 standards. The solubility of the PSs was similar to the Grossman sealer (p>0.05); but significantly greater than the AH Plus (p<0.05). Regarding the inter-group comparison of the pH, the aqueous extracts of all PSs had either similar or significantly greater pH compared with those of the Grossman sealer or AH Plus (p<0.05). Significant differences were also found in the intra-group analyses (p<0.05) with a general tendency of an increase in the pH values with time. As for the microleakage, the highest values were seen in PS5 and the Grossman sealer (p>0.05; the two were similar), and the lowest values were seen in AH Plus; PS10, PS25 and PS50 had intermediate microleakage. Conclusion: The PSs are promising for possible future clinical use as most of their physical properties were in accordance with the ISO 6876/2001 standards. Besides, their microleakage values were less than the Grossman sealer, and their aqueous extracts revealed favorable pH