I am planning on tiling a Denshield wall which is surrounded by two finished drywall walls (inner corners). Do I need to tape the edges, or am I ok with a bead of silicone?
Assuming the following scenario, I don't think taping offers much. If there's movement in the framing at the corner, tape isn't going to help. Your plan to caulk is probably fine. I'm not sure I'd use silicone, though. It's not paintable. An acrylic-silicone blend or flexible grout would be better.
____________________________________ | | ^--backer board | | tile |--|______________________ | ^--caulk | |<-- existing painted drywall | |