Hello Meng Fai Chew,
There are several reasons for having pain on chewing. It could be that the denture is loose and moving around when she bites and that movement hurts her gums. If so, the denture will need to be adjusted or modified to fit her gums better.
Your mother has been wearing full dentures for nearly 30 years. Many people do not know that when teeth are extracted, the jaw bone shrinks because the bone is no longer needed to hold teeth. It is very similar to your muscles. If you do not use your muscles to do exercise, then the muscles will shrink.
If your mother is wearing a denture that was made a long time ago, it would no longer be fitting against the current shape of her bone. To compensate for the bone shrinkage, it is generally advised to have dentures remade or modified every 3 - 5 years.
If your mother has just got a new set of dentures made, then it is just a matter of going back to the dentist for some adjustments. Using new dentures is just like using new shoes - expect some pinching here and there.
Sometimes, in extreme cases of bone shrinkage, it may be very difficult to make dentures that are truly stable. Your mother may consider using denture adhesives or other treatment options like implants.
In any case, the best thing to do is to take your mother to a dentist to diagnose the cause of the problem and take the necessary action.
