This study compared the depth and percentage of dentinal tubule penetration for single‐cone (SC) and warm vertical (WV) obturation techniques with two different bioceramic sealers (BC Sealer [BCS], BC Sealer HiFlow [BCSHF]) and an epoxy resin‐based sealer (2Seal easymiX). Fifty canals were filled with BCS, BCSHF or resin‐based sealer (RBS). Teeth in BCS and BCSHF groups were filled with SC or WV techniques, and teeth in the control group (RBS) filled with WV technique only. The roots were sectioned at 3 mm and 6 mm levels from the apex and evaluated with a confocal laser microscope. There was significantly greater depth and percentage of sealer penetration at the 6 mm section compared to 3 mm (P < 0.05). No statistically significant difference was found in sealer type or obturation technique at the examined levels (P > 0.05). In conclusion, dentinal tubule penetration was similar comparing BC Sealer, BC Sealer HiFlow and RBS using SC and WV techniques.

Policies and pressures emanating from the 1972 Amendments to the Federal Water Pollution Control Act favor the installation of cooling towers, or closedcycle cooling systems, in power plants. An assessment of the relative risks of alternative cooling system designs indicates that, in general, adverse environmental effects associated with cooling towers are more certain, are of larger scale, and are more likely to be irreversible than impacts associated with once-through cooling systems and cooling reservoirs. Adverse environmental effects associated with once-through cooling and cooling reservoirs are largely amenable to mitigation in the context of resource management principles. These factors, together with the greater costs associated with cooling towers, indicate that wherever the feasibility is demonstrated and there is minimal risk to aquatic ecosystems, once-through cooling systems or cooling reservoirs should be preferred.

No abstract

No abstract

No abstract