Root resorption potentials of granulation tissue from bone and flap connective tissue

The present study was designed to examine the early phases of healing following root implantation in an attempt to compare the potentials of granulation tissue from bone and flap connective tissues to induce root resorption. Three adult beagle dogs with advanced periodontal disease were used and teeth 1 P 1 , 2 P 2 , 4 P 4 , 1 M 1 , and 3 I 3 were extracted to provide implantation sites. Eight weeks later, the root canals of the remaining premolars were filled with guttapercha. Using a flap procedure, the exposed root surfaces were thoroughly planed and the crowns were resected. The roots were then extracted and implanted in grooves prepared in edentulous areas with half the circumference of the root lying in the osseous groove and the other half of the root lying in contact with connective tissue of the mucoperiosteal flap. On one side of the mouth, the planed root surfaces were conditioned with citric acid for 3 minutes before implantation. Histologic sections cut in the transverse axis of the roots were evaluated at 2 wk (non‐acid treated) and 3 wk (acid‐treated) after implantation. Extensive root resorption and ankylosis were seen on the bone side of the acid‐treated (3 wk) and non‐acid treated (2 wk) roots. On the flap connective tissue side, connective tissue fibers were seen lying parallel to the root surface and resorption, when present, was minimal and usually confined to that part of the root close to the margins of the groove in bone. The results suggest that root resorption primarily originates from granulation tissue derived from bone. The potential of the flap connective tissue to induce root resorption is either less or delayed compared to the connective tissue derived from bone.