No, a dense design is one that has many stitches and underlay. A design for thick thread is one that is created to use with heavier wt threads, such as 12wt. I have tried to think f a example to post for you, but can not remember where I got them just now.
These are great tutorials;very clear and easy to grasp. I love the look of these designs, very rich and lush.TU,again.
They are not!
A dense design has a lot of stitches. It might even have too many stitches to be used on thin material without double layers of stabiliser.
A thick thread design on the other hand is far less dense than usual to accommodate the thicker thread, like wool or Madeira's "glamour thread". It would be unsuitable for normal embroidery thread.