Is it possible to request a deep cavity filling without being numbed.i know it use to be done years ago.i have lower molars with deep cavities. ?

Yes: Yes it can be done, but i wouldn't let anyone do it to me. I would expect it to really hurt. I have done fillings, root canals, even extracted teeth without local anesthesia. Usually this is for people that are phobic about needles. The dentist can do something for the fear.

Molars: Did you ever have severe pain in any of your lower molars? If not, it is still viable to protect your teeth with fillings. If decay is sitting close to the pulp or nerve (a good x-ray will be a good diagnostic tool), you rather have the area anesthetized so you won't have to feel pain during the procedure unless the decay is far from the pulp.

Fillings: Getting a filling deep or shallow can be done without being numb, but I have to wonder why? It is more comfortable for you while they are being done and it is better to not have you closing, stopping, jumping and twitching during the procedure. An open cavity is best filled when it is not contaminated with saliva and the germs it contains. If they are that deep it might progress to something more.

Tolerate the pain?: It's your body and if you think you can tolerate the pain associated with the preparation (drilling) of a deep cavity, than tell your dentist you'd like to try. If during the procedure, it becomes to uncomfortable , you can always get local anesthesia to complete it. The last thing you want, is to have the decay left behind under your new filling, because you couldn't tolerate the pain.