Hi,
Regarding dentures...
Say you are sitting on your couch. Your feet are underneath the coffee table. You point your sword fingers at your foot to clear a blockage...
Does the energy reach your foot, or does the table block the qi?
You can, easily clear the foot. The energy you are projecting through your sword fingers is the same energy moving in small universe. I don't see dentures blocking energy flow.
It is fun to try this type of exercise. Say, hold your hand under a table surface with an open palm. With your other hand, point your sword fingers at that palm and draw a circular pattern on the palm. Keep circling it and see if you can feel the energy. Stay relaxed and open..
There are times in small universe where I clearly feel energy in the areas of focus, and times that I don't. I feel great benefit from the exercise, either way. The physical sensations seem to come more when I am at a higher level within my own practice, or have stored more energy to move around. The tongue connection has never been a concern in my own practice. I just focus on the areas, and I have never thought about it. It is good to remember that the mind moves the energy. Move from the third eye area, to the throat. You don't have to track through the middle of that and check the tongue connection/feeling.
You move from focus area to focus area, and 'lead' the qi. The energy follows your lead.
The ability to do long distance healing, also shows us that energy travels, unhindered by physical objects between us and who we are helping.
love,
gallen