Hello, please tell me why my grandmother gets numbness in the upper lip when she's wearing her denture? (upper jaw denture)

Ill-fitting denture: The denture could be ill-fitting. The ill-fitting denture could be impinging on a nerve bundle or reducing blood supply, therefore causing numbness. A potential quick-fix could be a denture adjustment, or a soft reline. Otherwise she may need a new denture.

Needs adjustment.: Numbness most likely is from too much pressure on the tissue under the lip. A simple denture adjustment fixes that. A less likely possibility is an allergy to the material the denture is made of. A visit to the dentist will be needed to determine which cause it is and to take the proper steps ti remedy.

Bone loss: She probably has lost so much bone that the covering over her nerve has been lost. When she wears her denture it puts pressure on the nerve and she feels the numbness. She should see a prosthodontist to evaluate this and recommend treatment so she can be more comfortable.

Pressing on a nerve: Grand mom may have so little bone that the denture is pressing against a nerve that exits the jaw below each eye. Pressure on the nerve will result in numbness. Te denture needs to be adjusted to alleviate this pressure.