Histomorphometric study of the stability of newly formed bone after elevation of the floor of the maxillary sinus.

We studied the remodelling process of newly formed bone and the distribution of osteoclasts in the augmented space after elevation of the floor of the maxillary sinus in rabbits. Histologically, 10 weeks after grafting, there was some newly formed lamellar bone embedded in fatty tissue. Histomorphometric analysis showed that the augmented height and augmented area decreased significantly from 2 to 6 weeks. The number of osteoclasts on newly formed bone, adjacent to the elevated sinus membrane, was significantly greater than in the augmented space at 2 and 4 weeks. We conclude that newly formed bone in the augmented space after grafting with blood clot is unstable during the early stage of bony regeneration.