Early healing after ridge preservation with a new collagen matrix in dog extraction sockets: preliminary observations.

: The aim of the present animal study was to investigate the early healing processes developing in the post-extraction sockets preserved with a new-marketed collagen matrix as, to our knowledge, such investigations have not been reported so far. In both quadrants of the mandible of a mongrel dog, the distal sockets of the second premolars served as experimental sites for ridge preservation. The experimental site 1 was protected with a resorbable membrane and then with the collagen matrix. The experimental site 2 was filled with a xenograft and then covered with the collagen matrix. The samples were harvested after one month of healing. In both experimental sites, the bundle bone lining the inner surface of the alveolus was replaced with trabecular bone containing areas of woven bone. A continuous layer of osteoblasts could be observed on the surface of woven bone areas. Osteoclasts encased within resorptive lacunae lined the outer portions of bone walls for the experimental site 1. The trabecular bone occupied only the apical third of the socket in experimental site 1, but it was obviously more abundant in the experimental site 2, occupying also the central compartment of the socket. Moreover, the trabeculae of the bone occupying the inner area of the alveolus were thicker for the experiment site 2 than for experiment site 1, suggesting an increased osseous deposition in the latter situation. Our preliminary results suggest that the association collagen matrix plus xenograft may be a valuable method for ridge preservation.