An in vivo model to study migration of cells and orientation of connective tissue fibers in simulated periodontal spaces

An in vivo model is described to study the migration of cells into experimental “periodontal” spaces and the influence of the geometry of substrata on cell and fiber orientation. Roots of molars and cylinders of bone (from femur and tibia) were obtained from Sprague‐Dawley rats. All attached soft tissues were removed from the bone cylinders (BC) and roots by planing with curettes followed by collagenase treatment. The roots and BC were divided into experimental (roots in bone cylinders to simulate tooth‐socket relationship) and control groups. Following citric acid treatment for 3 min, pairs of experimental and control specimens were implanted subcutaneously in 20 Sprague‐Dawley rats. Histologic examination was done 3 and 6 weeks after implantation. Connective tissue cells had migrated into the experimental spaces of both experimental and control specimens at 3 and 6 weeks. The cell and fiber orientation varied between the groups, and a tendency towards functional orientation of fibers was seen in some experimental and control specimens. The orientation of connective tissue fibers appeared to be influenced also by the spatial relationship of substrata to which they attach.