A 57-year-old patient complains of tooth mobility and inability to eat. Objectively: the lower 35, 36, 37, 38, 44, 45, 46 and 48 teeth are missing; the 31, 32, 33, 34, 41, 42, 43, 47 teeth exhibit grade II mobility, their clinical crowns are low, tooth equator is not pronounced. What is the optimal denture construction in this case?