Periodontal osseous defects associated with vitally submerged roots.

1. Vital roots associated with periodontal osseous defects can be clinically submerged beneath a soft tissue flap. 2. Connective tissue fibers filled the submerged osseous defects and were oriented parallel to the root surfaces in the majority of cases. 3. New cementum lined the root surface at the base of two successfully submerged defects, but was not apparent on the dentin amputation sites of any submerged roots. 4. Eight of the nine clinically submerged defects exhibited positive radiographic changes. The six control defects showed no positive radiographic changes. 5. All successfully submerged defects showed histologic evidence of new bone formation. New bone formation was not apparent in any of the control defects or nonsubmerged defects. 6. Either no epithelium or only a narrow band of epithelium was associated with the successfully submerged roots. A connective tissue inflammatory infiltrate was not present within the submerged defects. 7. The defects of all control teeth and nonsubmerged experimental roots contained epithelial downgrowth accompanied by a chronic inflammatory response in the connective tissue. 8. Pulpal tissues associated with submerged roots appeared vital without significant degenerative or inflammatory changes. Pulpal tissue was continuous with overlying connective tissue.