hello inflammation in gums due to new dentures is quite commonly seen possible cause inculde 1.ill fitting denture i.e. the denture is too tight or too loose 2.also it is seen that placement of new denture in mouth causes hyper or hypo salivation. the later may also lead to inflammation 3.it is common that when a person gets his new denture , he tries to eat (in his exitement of havinng an entire set of denture ) things that are too hard to chew so what i would suggest is that you pay a visit to your dentist who will make the necessary fitting if the denture is ill fitting besides i would also advise your father to do the following things 1.luke warm saline rinses for 4-6 times daily so that the blood circulation in the ridges is maintained good 2.since denture puts a pressure on the residual ridge , so he should remove denture and let the tissues rest for sometime after every 3-4 hours 3.he can also use gum astringent after every rinse (which is to be done after removal of denture ).take a drop of gum astringent on the index finger and gently massage the residual ridge 4.he should not go to sleep wearing the denture.THE tissues also need rest 5.he should try soft diet initially for a few days and than switch slowly to normal diet 6.also sometimes it is seen that the denture is not properly cleaned before wearing,so what i would suggest is that he should clean the denture in running water with fingers before he wears them and when he removes the denture he should place the denture in clean water 7.for the time being he can take paracetamol or combiflame twice daily for 2-3 days to reduce the inflammation hope that helps best of luck