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Introduction The purpose of this study was to evaluate the effects of intraradicular moisture conditions on the push-out bond strength of root canal sealers. Methods Eighty root canals were prepared using rotary instruments and, thereafter, were assigned to 4 groups with respect to the moisture condition tested: (1) ethanol (dry): excess distilled water was removed with paper points followed by dehydration with 95% ethanol, (2) paper points: the canals were blot dried with paper points with the last one appearing dry, (3) moist: the canals were dried with low vacuum by using a Luer adapter for 5 seconds followed by 1 paper point for 1 second, and (4) wet: the canals remained totally flooded. The roots were further divided into 4 subgroups according to the sealer used: (1) AH Plus (Dentsply-Tulsa Dental, Tulsa, OK), (2) iRoot SP (Innovative BioCeramix Inc, Vancouver, Canada), (3) MTA Fillapex (Angelus Industria de Produtos Odontologicos S/A, Londrina, Brasil), and (4) Epiphany (Pentron Clinical Technologies, Wallingford, CT). Five 1-mm-thick slices were obtained from each root sample (n = 25 slices/group). Bond strengths of the test materials to root canal dentin were measured using a push-out test setup at a cross-head speed of 1 mm/min. The data were analyzed statistically by two-way analysis of variance and Tukey tests at P = .05. Results Irrespective of the moisture conditions, iRoot SP displayed the highest bond strength to root dentin. Statistical ranking of bond strength values was as follows: iRoot SP > AH Plus > Epiphany ≥ MTA Fillapex. The sealers displayed their highest and lowest bond strengths under moist (3) and wet (4) conditions, respectively. Conclusions The degree of residual moisture significantly affects the adhesion of root canal sealers to radicular dentin. For the tested sealers, it may be advantageous to leave canals slightly moist before filling.

The objective of this study was to investigate the synthesis of zeolites from paper sludge ash, and to evaluate their applications for water purification to simultaneously remove NH4+ and PO43- in aqueous solution. Paper sludge ash had a low abundance of Si and a significant Ca content, due to the presence of calcite that was used as paper filler. Na2SiO3 was added to the NaOH solution to increase Si content in order to synthesize zeolites with high cation exchange capacity. The original ash without addition of Si yielded hydroxysodalite with a cation exchange capacity of ca. 50 cmol/kg. Addition of Si to the solution yielded Na-P1 (zeolite-P) with a higher cation exchange capacity (ca. 120 cmol/kg). The observed concentrations of Si and Al in the solution during the reaction explain crystallizations of these two phases. The product with Na-P1 could simultaneously remove NH4+ and PO43- from the solution between pH 4 and 9.